Week 1 Flashcards
(196 cards)
What are the three categories of hormones?
- protein/peptide
- amino acid derivatives
- Lipid based
Describe the following hormonal rhythms
1. ultradian
2. circadian
3. circalunar
4. circannual
- oscillation of less than 24 hours
- follow roughly 24 hour cycle
- corresponds to lunar cyclce (approx 29.5 days)
- yearly
Receptors for water soluble hormones are found where?
What about receptors for lipid solube hormones?
- cell surface
- intracellularly
Hormone levels are most commonly measured by what analysis technique?
ELISA - using specific antibodies
Peptide hormone
1. water soluble?
2. uses carrier protein in plasma?
3. Stored in vesicle prior to secretion?
- yes
- No (but IGFs and GH have binding proteins in circulation)
- Yes
Steroid hormone
1. water soluble?
2. uses carrier protein in plasma?
3. Stored in vesicle prior to secretion?
- No
- Yes
- NO
Catecholamine hormone
1. water soluble?
2. uses carrier protein in plasma?
3. Stored in vesicle prior to secretion?
- Yes
- No
- Yes
Thyroid hormone
1. water soluble?
2. uses carrier protein in plasma?
3. Stored in vesicle prior to secretion?
- No
- Yes
- No (bound to thyroglobulin)
Peptide hormone
1. Receptor location at target cell?
2. MOA (2nd messengers, altered gene expression, or gene transcription)
3. Speed and duration of action
- Plasma membrane
- 2nd messengers
- Usually fast onset but short acting responses
Steroid hormone
1. Receptor location at target cell?
2. MOA (2nd messengers, altered gene expression, or gene transcription)
3. Speed and duration of action
- Intracellular
- Altered gene expression
- Usually slow onset but long lasting responses
Catecholamine hormone
1. Receptor location at target cell?
2. MOA (2nd messengers, altered gene expression, or gene transcription)
3. Speed and duration of action
- Plasma membrane
- 2nd messengers
- Fast onset but short acting responses
Thyroid hormone
1. Receptor location at target cell?
2. MOA (2nd messengers, altered gene expression, or gene transcription)
3. Speed and duration of action
- Nucleus
- Gene transcription
- Usually slow onset but long lasting responses
- How are protein hormone synthesized?
- How are they secreted
- hormone coding genes need to be transcribed first into mRNA
- Synthesis of peptide hormone is done in rough ER lumen and hormones remain in rough ER
- In the golgi apparatus, if needed, some hormones are cleaved into biologically active hormones
- all protein hormones are stored in secretory granules that bud off of golgi apparatus
- Stimulation of endocrine cells will cause fusion of granules and release of hormones
What two groups of hormones are derived from tyrosine?
- catecholamines
- thyroid hormones (iodine is attached to the tyrosine residues of a protein called thyroglobulin)
- What are the two catecholamine hormones?
- What are they released by?
- epinephrine and norepinephrine
- Adrenal medulla is the main source of circulating epinephrine. Then epinephrine can be converted to dopamine and then NE. NE is released by most catecholamine producing cells of the body.
- Where are steroid hormones produced? (4)
- adrenals, ovaries, testes, and placenta
Where are hormone binding proteins synthesized?
Liver
Hormone actions can be controlled by what 4 things?
- rate of secretion
- plasma binding
- rate of elimination
- peripheral conversion
Ion channel receptors
1. MOA
2. They regulate levels of what?
3. Lead to activation of what?
- Hormone binds to these receptors and they open ion channels - lead to increase of intracellular Calcium
- Calcium levels
- Activation of enzymes such as PKC and calcium calmodulin kinase
What is the structure of a receptor tyrosine kinase (3 main parts)
- amino-terminal extracellular domain
- Single transmembrane domain
- carboxy termianl intracellular domain that has intrinsic enzymatic activity
How are cytokine receptors different than receptor tyrosine kinase?
- For cytokine receptor - a separate soluble enzyme (like JAK, a tyrosine kinase) associates with the intracellular domain of the cytokine receptor
Remember that in receptor tyrosine kinase the intracellular part is the enzyme
The G-protein coupled receptors have 3 subunits (alpha, beta, gamma) - which binds GTP or GDP and functions as primary signal transducer
alpha subunit
What receptor exists as dimers or dimerize after binding of ligand?
Receptor Tyrosine kinase and also cytokine receptor
Once a steroid hormone binds intracellular receptor what occurs to cause a change?
- hormone-receptor complex binds DNA and activates transcription directly