Chapter 7 - Endocrine System

Where are amino acid derived hormones derived from?... ha

Either tryptophan or tyrosine

After passing through the golgi apparatus and being released into a vesicle, what happens to a prohormone?

Enzymes within the secreted vesicle cleave peptide segments of the prohormone, creating an active peptide hormone that will be effective as soon as it is secreted into the blood stream.

Which hormones create new proteins and which modify existing hormones?

New: Steroid and Thyroid hormones Existing: Peptide and Catecholamines

What is the main purpose of the plasma proteins in the blood that carry steroid hormones?

Since steroid hormones are hydrophobic they can easily slip across cell membranes. This means that as soon as they are released from a cell they can slip into another cell. Plasma hormone carrying proteins help ensure that the steroid hormone has a long term and wide spread effect through out the body, to ensure that the proper target cell is effected.

Where does cholesterol come from?

Squalene

What type of hormones do plasma carrier proteins in the blood help carry?

Steroid Hormones and Amine Thyroid hormones

What hormones actually alter nuclear transcription and translation?

Steroid hormones and thyroid hormone

What amino acid is the parent for catecholamines and thyroid hormones?

Tyrosine

What is the predominate estrogen in females during reproductive years?

Estradiol

T/F - Steroid hormones are stored in vesicles

False. Steroid hormones are synthesized on demand, when a stimulus presents the need.

T/F - Steroid hormones cannot pass through the cell membrane.

False. They can pass right through directly effecting transcription and expression of various genes, acting as a second messenger system.

How do peptide or protein hormones activate cells?

G-protein coupled receptors

What type of hormones have second messenger effects?

Hormones that bind to the cell membrane. Mainly peptides and catecholamines. Sometimes Steroid hormones as well.

Where are steroid hormone receptors typically located?

In the cytoplasm or the nucleus

Pre-prohormone and prohormone are both what?

Inactive hormones

What is the general response of target cells after being effected by peptide, steroid, or thyroid hormones?

Induction of new protein synthesis

What kind of half life do steroid hormones have?

Long half lives because they are bound to plasma protein carriers.

What are steroid hormones made from? What properties does this give it?

Made from cholesterol. Can easily pass through lipid bilayers and go straight to the nucleus to alter transcription.

How are steroid hormones stored?

Made on demand

Do hormones typically respond through positive or negative feedback systems?

Negative

List 3 specific catecholamines.

Norepinephrine, epinephrine, Dopamine.

Where are the location of receptors located for thyroid hormones?

On the surface of the nucleus

Which type of hormones are made in advance and stored in vessicles?

Peptide hormones

What type of hormones MUST combine with membrane proteins to induce a signaling transduction process within it's target cell?

Peptide hormones and catecholamines.

What type of hormones activate or repress gene expression through cytoplasmic or nuclear receptors?

Peptide, Steroid and thyroid hormones

What hormones effect their target cells by activating protein receptors embedded in the cell membranes of their target cells?

Peptide, steroid hormones and catecholamines.

What type of hormones are made in advanced and stored in vesicles awaiting a signaling message for them to be exocytosed?

Peptide, thyroid and catecholamine hormones.

What hormones have genomic effects and what does that mean?

Steroid hormones. They can activeate or repress genes for protein synthesis.

Where is estridiol produced from?

Testosterone

From what hormone comes estradiol and what catalytic enzyme is involved.

Testosterone is altered by aromatase into estradiol

What part of a preprohormone is cleaved off by enzymes upon entering the ER? What does preprohormone become after cleaving?

The signaling sequence. Preprohormone becomes a prohormone within the ER.

What can a steroid hormone and nuclear receptor do once they are bound together?

They can act as a transcription factor or inhibitor, either activate or repress gene transcription.

How do hormones typically regulate themselves?

Through negative feedback loops.

Which amine hormone alters nuclear transcription?

Thyroid hormone

What type of hormones are bound to carrier proteins?

Thyroid hormones and steroid hormones

T/F Steroid hormones activate receptors located on the surface of cell membranes.

True. Steroid hormones are created from long carbon chains (Squalene) which gives them hydrophobic interactions allowing them to slip past the membrane and directly effect nuclear transcription. However, there are also receptors on the the cell membrane that steroid hormones can bind to, to initiate rapid second messenger responses.

T/F - Hormones can still have a physiological effect at low concentrations.

True. There only needs to be a bit of hormones to trigger receptors which initiate a response.

From what 2 amino acids are most amine hormones derived from?

Tryptophan (W) and Tyrosine (Y)

What type of hormones are simply diffused into the blood plasma for transport?

Catecholamines and Peptide hormones

What hormones are responsible for modification of existing proteins?

Catecholamines and peptides

What hormones have receptors on the cell membranes?

Catecholamines, Steroid, and peptide hormones

What type of hormones activate second messenger pathways?

Catecholamines, steroid, and peptide hormones

What is the parent compound for all steroid hormones?

Cholesterol

Where do steroid hormones come from?

Cholesterol

What are some examples of amino acid derived hormones?

1) Catecholamines - Epinephrine - Norepinephrine - Dopamine 2) Melatonin 3) Thyroid hormones

What types of hormones activate cells via g-protein coupled receptors?

- Peptide or Protein Hormones - Catecholamines

What are similar cellular effects of steroid and thyroid hormones?

Activating of gene transcription

Melatonin, Catecholamines and Thyroid hormones are all examples of what type of hormone?

Amine hormones

What type of hormones are derived from single amino acids?

Amine hormones

What types of hormones are associated with G-Coupled Protein Receptors?

Amine, Peptide and Protein Hormones.