Endocrinology Quiz 1 - Practice Questions

Testes are the target for which of the following hormones (choose best answer): A. TSH B. Testosterone C. Prolactin D. Thyroxin E. FSH

E. FSH [See picture]

Which of the following statements about hypothalamic releasing hormones is true? a) They are secreted into capillaries in the median eminence b) They are transported by portal veins to the posterior pituitary c) They stimulate the secretion of specific hormones from the posterior pituitary d) all of the above(a-c) are true e) none of the above are true

a) They are secreted into capillaries in the median eminence [Hypothalamic Releasing Hormones: Releasing hormones are secreted in the capillaries of the median eminence to go to the *anterior* pituitary. (Neurosecretory cells in the hypothalamus are what send them to the posterior pituitary!) They are transported by portal veins to the *anterior* pituitary (not the posterior - neurosecretory cells send them to the posterior pituitary). They stimulate the secretion of specific hormones from the *anterior* pituitary (Hypothalamus sends them to the posterior pituitary which sends them directly into the blood, no other secretion is made there).]

A major action of oxytocin is to cause: A. increased blood oxygenization B. uterine contraction C. ovulation D. oxygen retention

B. uterine contraction [Oxytocin causes: - Contraction of lactiferous ducts = "milk letdown" or "milk ejection" -Uterine contractions]

The pititutary hormone that controls the release of corticosteroids from the adrenal gland is: A: TSH B: ACTH C: CRH D: LH E: GH

B: ACTH [ACTH = Adrenocorticotropic Hormone --> Stimulates Corticosteroids (cortisol) produced in the Zona Fasiculata in the Adrenal Cortex] [Note: Corticosteroids increase blood glucose]

Experiments with a novel chemical find that it elicits an increase in cellular protein kinase C activity. The chemical is probably: A) a steroid B) activating a tyrosine kinase linked receptor C) activating a Gs linked receptor D) activating a Gq linked receptor E) epinephrine

D) activating a Gq linked receptor [Dr Giblin said: Think: *C*alcium = *C* in Protein Kinase *C* --> Calcium sounds like = "*q*oalcium!!!" (instead of Gc for calcium, it's G*q*) Gq linked receptor --> activates phospholipase c (aka PLC) Phospholipase C cleaves PIP2 into IP3 and DAG DAG activates the enzyme protein kinase C.] [See "DAG and IP3 mechanisms"]

Which of the following inhibits the secretion of growth hormone (choose best answer)? a. Sleep b. Stress c. Puberty d. Somatomedins e. none of the above

d. Somatomedins [Somatomedins inhibit the secretion of growth hormone by acting directly on the anterior pituitary and by stimulating the secretion of somatostatin from the hypothalamus] [KNOW DIFFERENCE BETWEEN Somatostatin vs Somatomedin]

Match the following hormones (numbered 3 - 6 below) with the primary agent (a - e) that stimulates its release: a. TSH b. ACTH c. Growth hormone d. Sympathetic nerves e. CRH 1. Epinephrine ___ 2. Thyroxine ___ 3. Corticosteroids ___ 4. ACTH ___

1. Epinephrine *D* <-- Sympathetic nerves 2. Thyroxine *A* <-- TSH [Thyroid Stimulating Hormone] 3. Corticosteroids *B* <-- ACTH [Adrenocorticotropic Hormone] 4. ACTH *E* <-- CRH [Cortico-tropin releasing Hormone]

Match the following intracellular signaling mechanism with the hormones listed below: a. cAMP b. DAG-IP3 c. Steroid d. Activation of Tyrosine kinase e. Can be a or b above, depending on target cell and receptor 1. Oxytoxcin ___ 2. ADH ___ 3. Insulin ___ 4. Testosterone ___

1. Oxytoxcin *B* <-- DAG-IP3 2. ADH *E* <--cAMP or DAG-IP3 depending on target cell 3. Insulin *D* <--Tyrosine kinase 4. Testosterone *C* <--Steroid

Which of the following increases with elevated thyroid hormone? A) basal metabolic rate B) fat stores C) body weight D) skin dryness

A) basal metabolic rate [Thyroid Hormone is known as both T3 + T4 T3 + T4 stimulate the basal metabolic rate (BMR). Therefore, elevated thyroid hormone increases BMR.] [Elevated Thryoid Hormone = *HYPER*thyroidism inc. basal metabolic rate = *hyper*thyroidism inc. fat stores = hypothyroidism inc. body weight = hypothyroidism inc. skin dryness = hypothryoidism]

Which of the following hormones acts on its target tissues by an intracellular receptor signaling mechanism of action? A. Thyroid hormone B. Parathyroid hormone (PTH) C. Antidiuretic hormone (ADH) on the collecting duct D. beta adrenergic agonists E. Glucagon

A. Thyroid hormone A: Thyroid hormone [Thyroid Hormone = T3 + T4 THYROID HORMONES ARE STEROIDS Steroids use intracellular receptors, meaning that they pass through the membrane without using a 2nd messenger system. Steroids then bind with a receptor protein inside the cell cytoplasm to create a complex Complex goes to the nucleus to stimulate mRNA Transcription from DNA --> creates more proteins from those specific genes One purpose of creating proteins are to carry out reactions for a specific response (in this case, This is known as "GENE EXPRESSION" This is different from hormones that use a 2nd messenger system --> they use a messenger in the cytoplasm to activate proteins that have already been made.] [Steroid Hormones: INTRACELLULAR RECEPTORS "VETTT CAP" The VET on STEROIDS is wearing a baseball CAP V Vitamin D3 E Estrogen T Testosterone T T3 (Triiodothyronine) ***** T T4 (Thyroxine) ***** C Cortisol A Aldosterone P Progesterone]

Hormones released from the anterior pituitary are: A. Trophic B. Steroid C. Neuroendocrine D. Amine

A. Trophic [Trophic hormones stimulate the activity of another endocrine gland.] [*Hormones released by A.P.*: FLAT PIG" FSH LH ACTH TSH PRL (I - Ignore) GH]

Which of the following hormones acts on its target tissues by increasing gene expression? A: Cortisol B: Parathyroid hormone (PTH) C: Antidiuretic hormone (ADH) D: beta adrenergic agonists E: Glucagon

A: Cortisol [Cortisol is a STEROID Steroids use intracellular receptors, meaning that they pass through the membrane without using a 2nd messenger system. Steroids then bind with a receptor protein inside the cell cytoplasm to create a complex Complex goes to the nucleus to stimulate mRNA Transcription from DNA --> creates more proteins from those specific genes One purpose of creating proteins are to carry out reactions for a specific response (in this case, This is known as "GENE EXPRESSION" This is different from hormones that use a 2nd messenger system --> they use a messenger in the cytoplasm to activate proteins that have already been made.] [Steroid Hormones: "VETTT CAP" The VET on STEROIDS is wearing a baseball CAP V Vitamin D3 E Estrogen T Testosterone T T3 (Triiodothyronine) T T4 (Thyroxine) C Cortisol ***** A Aldosterone P Progesterone]

Which of the following increases the gene expression? A: Thyroid hormone B: Vitamin B12 C: Antidiuretic hormone (ADH) D: Beta adrenergic agonists E: Glucagon

A: Thyroid hormone [Thyroid Hormone = T3 + T4 Steroids use intracellular receptors, meaning that they pass through the membrane without using a 2nd messenger system. Steroids then bind with a receptor protein inside the cell cytoplasm to create a complex Complex goes to the nucleus to stimulate mRNA Transcription from DNA --> creates more proteins from those specific genes One purpose of creating proteins are to carry out reactions for a specific response (in this case, This is known as "GENE EXPRESSION" This is different from hormones that use a 2nd messenger system --> they use a messenger in the cytoplasm to activate proteins that have already been made.] [Steroid Hormones: INTRACELLULAR RECEPTORS "VETTT CAP" The VET on STEROIDS is wearing a baseball CAP V Vitamin D3 E Estrogen T Testosterone T T3 (Triiodothyronine) ***** T T4 (Thyroxine) ***** C Cortisol A Aldosterone P Progesterone]

A goiter is due to A. activation of TSH receptors B. hyperthyroidism C. hypothyroidism D. activation of TRH receptors

A: activation of TSH receptors [Goiter --> Activation of the TSH receptors]

Hormones secreted from the posterior pituitary: A: are produced by neurosecretory cells in the hypothalamus B: are transported in the hypothalmohyophysial portal system C: include GH and ACTH D: are classified as pheromones

A: are produced by neurosecretory cells in the hypothalamus [*Neurosecretory cells in the hypothalamus* synthesize hormones to send to posterior pituitary which goes directlyinto the blood, there are no cells that create/secrete any hormones in the posterior pituitary. They come straight from the hypothalamus! Neurosecretory cells secrete hormones into: *Capillary plexus of posterior pituitary* (neurohypophysis) --> ADH, oxytocin Hypophyseal portal system: The system of blood vessels that link the hypothalamus and the anterior pituitary in the brain --> NOT the posterior pituitary GH and ACTH are from A.P. ADH & oxytocin are both steroids, not pheremones.]

Insufficient ADH (antidiuretic hormone) production results in: A: increased urine volume B: decreased blood osmolality C: increased blood volume D: decreased urine volume

A: increased urine volume [Insufficient ADH = Increased Urine Volume + Increased Blood Osmolality] [ADH stimulates the reabsorption of water in the kidney If there is not enough ADH, there is little to no reabsorption of water (in the kidney) to send to the blood. More water in kidneys --> More water in urine = *Increased Urine Volume* *Insufficient ADH:* Increased urine volume Increased blood osmolality (less water means a higher concentration of solutes in the blood)]

Increased adrenocorticotropic hormone (ACTH) secretion would be expected in patients A: with chronic adrenocortical insufficiency (Addison's disease) B: with primary adrenocortical hyperplasia C: who are receiving glucocorticoid for immunosuppression after a renal transplant D: with elevated levels of angiotensin II

A: with chronic adrenocortical insufficiency (Addison's disease) [CRH Stimulates adrenal cortex Adrenocortical hyperplasia --> puts out more cortisol, creates negative feedback, which leads to less produced by the anterior pituitary because the hyperplastic cells are producing too much for them.]

Some cells secrete chemicals into the extracellular fluid that act on cells in neighboring tissue. Which of the following terms best refers to this type of regulation? A) Endocrine B) Paracrine C) Neuroendocrine D) Autocrine

B) Paracrine [Endocrine: releases hormone into blood Paracrine: releases hormone to neighboring cells Neuroendocrine cells: are cells that receive neuronal input and, as a consequence of this input, release message molecules (hormones) to the blood Autocrines: affects same cells that secreted them]

Which of the following inhibits the secretion of growth hormone (choose best answer)? A) Sleep B) Somatomedins C) Puberty D) all of the above (a-c) E) none of the above (a-c)

B) Somatomedins [*Negative feedback control by somatomedins:* Somatomedins are produced when growth hormone acts on target tissues. Somatomedins inhibit the secretion of growth hormone by acting directly on the anterior pituitary and by stimulating the secretion of somatostatin (aka SRIF = "somatropin release-inhibiting hormone* SRIF) from the hypothalamus. SRIF from the hypothalamus then inhibitis the secretion of growth hormone in the anterior pituitary.] [KNOW DIFFERENCE BETWEEN Somatostatin vs Somatomedin]

In order to make thyroid hormone, follicular cells uptake A. Iodide via facilitated transport B. Iodide via sodium coupled transport C. Iodine via facilitated transport D. Iodine via sodium coupled transport

B. Iodide via sodium coupled transport [See picture - "sodium-iodide symporter" Iodide comes through a plasma membrane (from blood) along with a sodium --> aka "coupled transport"]

Melatonin is a(n) A. peptide hormones B. amine hormones C. steroid hormones D. glycoprotein hormones

B. amine hormones ["The pineal gland •secretes melatonin *(amine hormone)* in response to activity of suprachiasmatic nucleus (SCN) of hypothalamus.] [AMINE HORMONES: Melatonin Epinephrine Norepinephrine Thyroid Hormone (T3+T4)]

Vitamin D3: A. must be obtained in the diet (i.e. a true vitamin) B. is a steroid hormone C. is the most active form of Vitamin D D. activates G protein linked receptors

B. is a steroid hormone [Vitamin D3 is named "cholecalciferol". It is a fat-soluble vitamin (acts as a steroid) that helps your body absorb calcium and phosphorus --> passes through the membrane easily so it does *not* need a secondary messenger (g-protein linked receptor) Steroids are lipids derived from cholesterol] [Vit. D3 can be from sun or diet] [NOTE: The active form of vitamin D is 1,25-dihydroxycholecalciferol.--> NOT VITAMIN D3] [Steroid Hormones: INTRACELLULAR RECEPTORS "VETTT CAP" The VET on STEROIDS is wearing a baseball CAP V *Vitamin D3* E Estrogen T Testosterone T T3 (Triiodothyronine) T T4 (Thyroxine) C Cortisol A Aldosterone P Progesterone]

Blockage of the hypothalamo-hypophyseal portal system between the hypothalamus and the anterior pituitary would result in A. increased ACTH secretion B. increased prolactin secretion C. increased FSH secretion D. increased growth hormone secretion

B. increased prolactin secretion [PIH also known as Dopamine] [Anterior pituitary is blocked. Hormones normally secreted by hypothalamus: Corticotropin RH ("GRH")--> stimulates ACTH secretion Gonadotrophin RG ("GnRH") --> stimulates FSH (& LH) secretion Two for Growth hormone: GHRH and SRIF --> stimulates GH and the other inhibits GH. *But prolactin is also secreted by the Anterior pituitary. So why is it increased?*

Overproduction of somatotropin (growth hormone) in an adult (i.e., an individual with closed skeletal physes) will result in: A: achondroplasia B: acromegaly C: giantism D: osteogenesis imperfecta tarda

B: acromegaly [Acromegaly is a disorder that results from excess growth hormone (GH) after the growth plates have closed. Acromegaly is typically due to the pituitary gland producing too much growth hormone. In more than 95% of cases the excess production is due to a benign tumor, known as a pituitary adenoma.] [SIDE NOTE: Testosterone closes the epipheseal plates -- assc. with male repro questions]

A major action of oxytocin is to cause: A: increased blood oxygenization B: contraction of lactiferous ducts (milk letdown) C: ovulation D: oxygen retention

B: contraction of lactiferous ducts (milk letdown)

One effect of ADH (antidiuretic hormone) is to: A) increase urine volume B) increase blood osmolality (i.e. decrease the concentration of blood solutes) C) decrease blood volume D) decrease urine volume [NOTE: typo on old test about "increased concentration" --> correct format is here saying "decreased concentration"]

B: decrease blood osmolality (i.e. decrease the concentration of blood solutes) [Sufficient ADH = Decreased Urine Volume + Decreased Blood Osmolality] [ADH stimulates the reabsorption of water in the kidney to send to extracellular water volume. More water in extracellular water --> More water in blood = *Decreased Blood Osmolality* (Sufficient) ADH decreased urine volume and decreases blood osmolality (more water means a lower concentration of solutes in the blood)]

One effect of ADH (antidiuretic hormone) is to: A: increase urine volume B: decrease blood osmolality (i.e. decrease the concentration of blood solutes) C: decrease blood volume D: none of the above

B: decrease blood osmolality (i.e. decrease the concentration of blood solutes) [Sufficient ADH = Decreased Urine Volume + Decreased Blood Osmolality] [ADH stimulates the reabsorption of water in the kidney to send to extracellular water volume. More water in extracellular water --> More water in blood = *Decreased Blood Osmolality* (Sufficient) ADH decreased urine volume and decreases blood osmolality (more water means a lower concentration of solutes in the blood)]

Which hormone activates a tyrosine kinase linked receptor mechanism? A: testosterone B: insulin C: epinephrine D: prolactin

B: insulin [Tyrosine Kinase Linked Receptor: "I - I" Aye-Aye, Captain Tyrone! I = Insulin I = IGF-1 (insulin like growth factor)]

The pulsatile secretion of hormones: A) describes how all hormones are released B) prevents the up-regulation of secretory cells C) prevents the down-regulation of target cell receptors D) prolongs the half-life of hormones

C) prevents the down-regulation of target cell receptors [*Regulation of receptors:* the responsiveness of the target cells is regulated by the number or sensitivity of receptors *Down-regulation of receptors:* A decrease in the number or affinity of receptors for a hormone. Prolonged exposure to high concentrations of hormone *Desensitization avoided by the pulsatile secretion (Pulsatile secretion prevents down-regulation of target cell receptors)* *Up-regulation of receptors:* An increase in the number or affinity (sensitivity) of receptors for a hormone. (For example, in the ovary, estrogen up-regulates its own receptor and the receptor for LH, leading to ovulation.)]

Propylthiouracil can be used to reduce the synthesis of thyroid hormones in hyperthyroidism because it inhibits oxidation of: A. Triiodothryonine (T3) B. Thyroxine (T4) C. Iodide (I-) D. Thyroid-stimulating hormone E. Diiodotyrosine (DIT)

C. Iodide (I-) [See picture: I^-1 to I^0 conversion means oxidation - loss of an election (LEO says GER)] [Propythiouracil inhibits oxidation of Iodide = "T4 cleaved into T3] [Used in Hyperthyroidism treatment to decrease high T3 levels (because T3 is more potent than T4)]

TRH is the abbreviation for A. Thyroxine Releasing Hormone B. Thyroid Releasing Hormone C. Thyrotropin Releasing Hormone D. Thyroid Regenerating Hormones

C. Thyrotropin Releasing Hormone

Experiments with a novel chemical find that it elicits a decrease in cellular Protein Kinase A activity. The chemical is probably: A. a steroid B. activating a tyrosine kinase linked receptor C. activating a Gi linked receptor D. activating a Gq linked receptor E. epinephrine

C. activating a Gi linked receptor [Think: Cyclic *A*MP = *A* in Protein Kinase *A* G*i* linked receptor = *i*hibitory INHIBITS cAMP PATHWAY = DECREASE PROTEIN KINASE A [*Normal cAMP pathway:* Ligand stimulates *Gs receptor* (stimulatory) Alpha-subunit from G-protein then goes to adenylate cyclase Adenylate cyclase changes ATP to cAMP cAMP activates *Protein Kinase A* Protein Kinase A phosphorylates a protein to illicit a specific cellular response] [See "DAG and IP3 mechanisms"]

Experiments with a novel chemical find that it elicits an increase in cellular protein kinase A activity. The chemical is probably: A. a steroid B. activating a tyrosine kinase linked receptor C. activating a Gs linked receptor D. epinephrine

C. activating a Gs linked receptor [Think: Cyclic *A*MP = *A* in Protein Kinase *A* G*s* linked receptor = *s*timulatory Ligand stimulates *Gs receptor* Alpha-subunit from G-protein then goes to adenylate cyclase Adenylate cyclase changes ATP to cAMP cAMP activates *Protein Kinase A* Protein Kinase A phosphorylates a protein to illicit a specific cellular response] [See "DAG and IP3 mechanisms"]

Most hormones are A. amines B. steroids C. peptides D. none of the above

C. peptides [see picture]

The hypothalamic hormone that controls the release of corticosteroids from the adrenal gland is: A: TSH B: ACTH C: CRH D: LH E: GH

C: CRH [CRH (Cortico-tropin releasing Hormone) is released from the hypothalamus --> controls the release of ACTH (Adrenocorticotropic Hormone) in the anterior pituitary --> stimulates the adrenal cortex to produce Aldosterone, Cortisol, and Precursor Sex Hormones (androgens in both sexes).]

A hypothalamic hormone that regulates the release of growth hormone is: A: TSH B: ACTH C: GHIH D: LH E: GH

C: GHIH [*GHIH* = Growth Hormone Inhibiting Hormone (aka "Somatostatin" GHIH comes from the hypothalamus --> inhibits the release of Growth hormone in the Anterior Pituitary] [*REMEMBER*: Growth hormone is regulated by *TWO* hormones from the hypothalamus: GHRH = Growth Hormone Releasing Hormone *GHIH* = Growth Hormone Inhibiting Hormone *ALSO KNOWN AS Somatostatin*] [If GHIH or GRH are options, either of them are the answer]

The pituitary hormone that regulates the production of gonadal hormones is: A: GnRH B: ACTH C: FH D: LH E: GH

C: LH [FSH and luteinizing hormone (LH) work together in the reproductive system. *LH:* In both sexes, LH stimulates secretion of sex steroids from the gonads. MALES: LH binds to receptors on Leydig cells, stimulating synthesis and secretion of *testosterone*. FEMALES: a large preovulatory LH surge induces ovulation of mature follicles on the ovary. Residual cells within ovulated follicles proliferate to form corpora lutea, which *secrete the steroid hormones progesterone and estradiol*. *FH:* stimulates maturation of of sex cells in both sexes FEMALES: stimulates the maturation of ovarian follicles. MALES: critical for sperm production. It supports the function of Sertoli cells, which in turn support many aspects of sperm cell maturation. REMEMBER: FSH helps in the maturing of the egg inside the follicle. LH or luteinizing hormone comes into play once the egg is mature inside the follicle by creating gonadal hormones. Do not mix up the two.]

TRH is the abbreviation for A: Thyroxine Releasing Hormone B: Thyroid Releasing Hormone C: Thyrotropin Releasing Hormone D: Thyroid Regenerating Hormones

C: Thyrotropin Releasing Hormone [Tropin hormones are hormones that induces the release of other hormones. (As in all "releasing" hormones are considered tropin hormones) A tropic hormone is a hormone that stimulates an endocrine gland to grow and secrete it's hormones.]

Oxytocin causes: A: increased gene expression B: increased Protein Kinase A activity C: increased Phospo Lipase C activity D: all of the above

C: increased Phospo Lipase C activity [G-protein activates phospholipase C in the following secondary messengers: IP3 DAG Ca2+] [*Hormones that use IP3 2nd Messenger (IP3/DAG/CA2+): * "GOA(1)T GA(1)A(2)" The Goat (says) Gaa G GnRH (Gonadotropin Releasing Hormone O *Oxytocin* A(1) ADH (Antidiuretic Hormone: V1 Receptor for blood vessels ONLY) T TRH (Thyrotropin Releasing Hormone) G GHRH (Growth Hormone Releasing Hormone) A(1) Alpha-1 Adrenergic Receptor A(2) Angiotensin II]

Hypothalamic releasing and inhibiting hormones: A: are secreted from the posterior pituitary B: are all neurohormones C: influence the release of hormones from the anterior pituitary D: affect target cells throughout the body

C: influence the release of hormones from the anterior pituitary [Hypthalamic releasing and inhibiting hormones are secreted from the hypothalamus Carried by hypothalamo-hypophyseal portal system directly to another capillary bed in anterior pituitary. Diffuse into anterior pituitary and regulate secretion of its hormones]

Which of the following statements are true about growth hormone? A: secretion stimulated by hypogylcemia B: secretion decreased by sleep C: secretion is regulated by GHRH and somatostatin D: causes inhibition of somatomedins in target cells

C: secretion is regulated by GHRH and somatostatin [Remember: Growth hormone is regulated by TWO hormones from the hypothalamus: GHRH = Growth Hormone Releasing Hormone *GHIH* = Growth Hormone Inhibiting Hormone *ALSO KNOWN AS Somatostatin*]

Which of the following is consistent with hyperthyroidism? A. Hypotension B. Bradycardia C. Decreased plasma levels of triiodothyronine (T3) D. Increased TSH

D. Increased TSH [*hyperthyroidism results in excessive thyroxine secretion*] [Autoimmune disease (Grave's Disease) where antibodies act like TSH --> stimulate thyroid gland to grow and oversecrete T3 + T4 or Adenoma of the Anterior pituitary (oversecretion of TRH --> oversecretion of TSH --> oversecretion of T3 + T4)]

The responses of target cells to hormones can result in A. altered enzyme activity within the cell B. altered protein production C. the insertion of transport proteins into the cell membrane D. all of the above

D. all of the above

Peptide hormones A. are made as inactive preprohormones and processed to prohormones in the endoplasmic reticulum B. are transported freely in blood plasma C. have a relatively short half life D. all of the above

D. all of the above [*Protein and peptide hormone synthesis:* o *preprohormone (INACTIVE)* synthesis occurs on the *rough endoplasmic reticulum* and is directed by a specific mRNA. o *signal peptides are cleaved from the preprohormone, producing a prohormone* (no biological activity), which is transported to Golgi apparatus for packing into secretory vesicles. o additional peptide sequences are cleaved inside vesicles to form the biologically active peptide hormone and inactive fragment, which are released together into the *blood circulation* upon stimulations. o this class of hormones are water-soluble and are released by exocytosis *The half-life of hormones circulating in the blood ranges from minutes to hours*: o Most hormones are removed from the blood by the liver.]

Receptor upregulation can occur due to: A. increased number of receptors B. increased responsiveness of receptors C. increased plasma concentration of hormone D. all of the above (a-c) E. none of the above (a-c)

D. all of the above (a-c) [*Regulation of receptors:* the responsiveness of the target cells is regulated by the number or sensitivity of receptors *Down-regulation of receptors:* A decrease in the number or affinity of receptors for a hormone. Prolonged exposure to high concentrations of hormone *Desensitization avoided by the pulsatile secretion (Pulsatile secretion prevents down-regulation of target cell receptors)* *Up-regulation of receptors:* An increase in the number or affinity (sensitivity) of receptors for a hormone. (For example, in the ovary, estrogen up-regulates its own receptor and the receptor for LH, leading to ovulation.)]

The pituitary hormone that increases blood glucose levels is: A: Glucagon B: Cortisol C: Erthyrpoietin D: ACTH E: Insulin

D: ACTH [ACTH = Adrenocorticotropic Hormone --> Stimulates Corticosteroids (cortisol) produced in the Zona Fasiculata in the Adrenal Cortex] [Note: Corticosteroids increase blood glucose]

Which of the following symptoms would you expect to observe in a person suffering from Diabetes Insipidus? A: Glucosuria B: Hyperglycemia C: Metabolic acidosis D: Increased thirst E: all of the above

D: Increased thirst [Diabetes Insipidus: disorder of salt and water metabolism marked by *intense thirst* and *heavy urination*. Not producing enough ADH --> no retention of water from kindeys --> creates "thirst" due to lack of water in blood volume]

If communication between the hypothalamus and anterior pituitary is disrupted, which of the following will increase A: ACTH B: FSH C: TSH D: Prolactin

D: Prolactin [Anterior pituitary is blocked. Hormones normally secreted by hypothalamus: Corticotropin RH ("GRH")--> stimulates ACTH secretion Gonadotrophin RG ("GnRH") --> stimulates FSH (& LH) secretion Two for Growth hormone: GHRH and SRIF --> stimulates GH and the other inhibits GH. *But prolactin is also secreted by the Anterior pituitary. So why is it INCREASED?* This is because the hypothalamus secretes *prolactin-inhibiting factor* (dopamine), which *inhibits the secretion of the prolactin* by the A.P. Note this difference because the majority of the hypothalamus hormones are *RELEASING* factors. *This means that prolactin will continue to be produced if there is no input from the blocked hypothalamus to stop it being produced*.]

Which of the following inhibits the secretion of growth hormone (choose best answer)? A: Sleep B: GHRH C: Puberty D: Somatomedins E: none of the above

D: Somatomedins [*Negative feedback control by somatomedins:* Somatomedins are produced when growth hormone acts on target tissues. Somatomedins inhibit the secretion of growth hormone by acting directly on the anterior pituitary and by stimulating the secretion of somatostatin (aka SRIF = "somatropin release-inhibiting hormone* SRIF) from the hypothalamus. SRIF from the hypothalamus then inhibitis the secretion of growth hormone in the anterior pituitary.] [KNOW DIFFERENCE BETWEEN Somatostatin vs Somatomedin]

Which of the following adrenal hormones activates an intracellular receptor? A: Aldosterone B: Cortisol C: androgens D: all of the above E: none of the above

D: all of the above [Steroid Hormones: INTRACELLULAR RECEPTORS "VETTT CAP" The VET on STEROIDS is wearing a baseball CAP V Vitamin D3 E Estrogen T *Testosterone* = *ANDROGENS* T T3 (Triiodothyronine) T T4 (Thyroxine) C *Cortisol* A *Aldosterone* P Progesterone]

Hormones secreted from the anterior pituitary: A: are produced by neurosecretory cells in the hypothalamus B: are transported in the hypothalmohyophysial portal system C: include GnRH and ADH D: are classified as trophic hormones

D: are classified as trophic hormones [Trophic hormones stimulate the activity of another endocrine gland.] [*Hormones released by A.P.*: "FLAT PIG" FSH LH ACTH TSH PRL (I - Ignore) GH]

Which of the following is inconsistent with the diagnosis of Graves' disease? A) Increased heart rate B) Exophthalmos C) Increased plasma levels of triiodothyronine (T3). D) Increased plasma levels of thyroxine (T4). E) Increased plasma levels of thyroid-stimulating hormone

E) Increased plasma levels of thyroid-stimulating hormone [*FALSE*] [Autoimmune disease (Grave's Disease): Antibodies act like TSH Stimulate thyroid gland to grow and oversecrete T3 + T4 = *hyperthyroidism* (excessive thyroxine secretion which leads to goiter) Too much T3 + T4 in blood sends negative feedback to anterior pituitary Because the antibodies are replacing function of TSH and over stimulating the production of T3 + T4, that means there is more negative feedback to both the hypothalamus for TRH and A.P. for TSH, which now does not create TSH in the first place --> *This decreases plasma levels of thyroid-stimulating hormone*.]

A dietary iodine deficiency causes: A) increased TSH production B) decreased T3 and T4 production C) increased TRH production D) thyroid enlargement E) all of the above

E) all of the above [Dietary iodine deficiency: Iodine is used to create T3 + T4 (the thyroid hormones) No iodine = No negative feedback inhibition of both TRH and TSH *TRH production increases* (since there is no inhibition) There is an *increased TSH production* (because there's no inhibition from T3+T4) (This leads to Goiter aka "thyroid enlargment" from too much TSH being produced) But since there's no iodine --> *decreased production of T3 + T4*]

What is a medicine treatment for hypothyroidism?

Levothyroxine It replaces or provides more thyroid hormone, which is normally produced by the thyroid gland.

Which describes the role of inositol triphosphate in hormone action? a. Activates adenylate cyclase b. Stimulates the release of calcium from endoplasmic reticulum c. Activates protein kinase d. All of the above

b. Stimulates the release of calcium from endoplasmic reticulum [*THINK:* IP*3* looks like *E* for Endoplasmic Reticulum] [IP3 is one of the 3 major hormone signaling mechanism] [Hormones that use IP3: GnRH TRH GHRH Angiotensin II]

The hormone primarily responsible for setting the basal metabolic rate and for promoting the maturation of the brain is a) cortisol b) ACTH c) Thyroxine d) TSH

c) Thyroxine [*Thyroxine is known at T4*, and Triiodothyronine is known as T3 Thyroxine is primarily responsible for setting BMR. Thyroxine regulates basal metabolic rate, blood pressure, glucose metabolism, heat production, growth and development.]

Which of the following statements about hypothalamic releasing hormones is true? a. They are secreted into capillaries in the median eminence b. They are transported by portal veins to the anterior pituitary c. They stimulate the secretion of specific hormones from the anterior pituitary d. all of the above (a-c) are true e. none of the above are true

d. all of the above (a-c) are true [o Releasing and inhibiting hormones from hypothalamus are released from axon endings into capillary bed in median eminence o Carried by hypothalamo-hypophyseal portal system directly to another capillary bed in anterior pituitary. o Diffuse into anterior pituitary and regulate secretion of its hormones] [NOT related to posterior pituitary cause they just go straight into blood]