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98 Cards in this Set

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  • Back
What are the glycoproteins that are made up of alpha and beta units and have their biological activities resident in the beta subuint.
What types of hormones typically bind to receptor in/on the cell surface?
Protein, peptide, and catecholamine hormones
What types of hormones typically bind to receptor inthe cell cytoplasm?
Steroid hormones
What types of hormones typically bind to receptor in the cell nucleus?
Thyroid hormones
What is the action of the "Adenyl Cyclase-cAMP Second Messenger System?"
1. GTP binds to G protein.
2. G protein activates (or inhibits) adenylate cyclase.
3. Activated adenylate cyclase catalyzes conversion of ATP to cAMP
4. cAMP activates PKA-->which phosphorylates specific proteins, producing highly specific physiologic actions
What are some of the hormones which utilize the Adenyl Cyclase-cAMP 2nd messenger system?
Angiotensin II
Vasopressin (V2 receptor)
What is the action of the Phospholipase C/IP3 Mechanism?
1. Hormone binds to receptor in the cell membrane via G protein and activates phospholipase C
2. Phospholipase C liberates DAG and IP3 from membrane lipids
3. IP3 mobilizes calcium from ER. Together, calcium and DAG activate protein kinase C--> which phosphorylates proteins and causes specific physiologic actions
What are some of the hormones that utilize the IP3 second messenger system?
GnRH, TRH, GHRH, Angiotensin II, ADH (V1), Oxytocin, alpha-r receptors
What is the action of the Ca--calmodulin mechanism?
1. Hormone binds to receptor in the cell membrane and : a) Opens cell membrane Ca channels & b) releases Ca from the ER
2. Ca binds to calmodulin and together, this complex produces physiologic actions
What does sTAR do?
Transport cholesterol into the mitochondria
What does 5-alpha-reductase do?
Converts testosterone to DHT
What does the SCC step do?
Converts cholesterol to pregnenolone.
What type of steroid is estrogen?

(C-18, C-19, or C-21?)
C-18 steroid, which have estrogenic activity
What type of steroid is DHEA?

(C-18, C-19, or C-21?)
C-19; which has androgenic activity and precursors to the estrogens
What type of steroid is androstenedione?

(C-18, C-19, or C-21?)
C-19; which has androgenic activity and precursors to the estrogens
What type of steroid is progesterone?

(C-18, C-19, or C-21?)
What does aromatase do?
Converts testosterone to estradiol
What type of steroid is deoxycoricosterone?

(C-18, C-19, or C-21?)
What type of steroid is aldosterone?

(C-18, C-19, or C-21?)
What type of steroid is cortisol?

(C-18, C-19, or C-21?)
What hormones can be derived from preproopiomelanocortin (POMC)?
2. Melanocyte-stimulating hormone (MSH)
3. Beta-endorphin
4. Beta-lipotropin
Which anterior pituitary hormone is primarily regulated by an inhibitory factor from the hypothalamus, but is also released by TRH?
Prolactin secretion is inhibited by dopamine.

Thyrotropin-releasing hormone (TRH) increase prolactin secretion.
What are the major regulated in catecholamine synthesis?
1. The major steps are the conversion of Tyrosine to L-Dopa (via tyrosine hydroxylase) and
2. The conversion of Norepi to Epi (phenylethanolamine-N-methyltransferase)
What is the rate-limiting step in catecholamine synthesis?
The rate limiting step (conversion of tyrosine to L-Dopa) occurs in the presence of the enzyme tyrosine hydroxylase.
What step in catecholamine synthesis is regulated by cortisol?
The conversion of Norepinephrine to Epinephrine occurs in the presence of phenylethanolamine-N-methyltransferase. The presence of cortisol causes greater conversion of Norepinephrine to Epinephrine.
What is the source of cholesterol for steroid secreting glands?
What is the rate limiting step in steroid synthesis?
Rate limiting step is the side chain cleavage (SCC) step in the conversion of cholesterol to pregnenolone
What are the zones of the adrenal gland?
1. Zona glomerulosa (outermost)
2. Zona fasciculata (middle)
3. Zona reticularis (innermost)
What hormones are associated with Zona glomerulosa?
Aldosterone (mineralocorticoid)
What hormones are associated with Zona fasciculata?
Glucocorticoids/cortisol and corticosterone
What hormones are associated with Zona reticularis?
Androgens (sex steroids) and DHEA
What are the effects of a 21OHlase deficiency?
21hydroxylase deficieny: loss of corticoid synthesis, which means an increase in adrenal androgens and a loss of negative feedback of ACTH so increased ACTH leads to HYPOTENSIVE patient (can’t retain water and sodium)
Causes androgenization of fetus, baby appears wrinkled and withered due to inability to retain water
What are the effects of a 21OHlase deficiency?
11--hydoxylase: High levels of DOC and 11-Deoxycortisol—this individual retains salt (Hypertensive patient)
Baby will have edema due to fluid retention (along with androgenization characteristics seen in 21-hydroxylase deficiency)
What are the androgens of the adrenal gland?
DHEA and androstenedione
What is the 17KS (ketosteroid assay)
The 17KS assay measures the amount of 17KS androgens present (remember: the 17-KS are DHEA and androstenedione)
What are the major steroids of the gonads?
Testosterone, Estrogen, Progesterone
What is meant by down-regulation?
A hormone decreased the number or affinity of receptors for itself or for another hormone
What is meant by up-reguation?
A hormone increases the number or affinity of receptors for itself or for another hormone
What hormones are released from the posterior pituitary?
ADH (or vassopressin) and Oxytocin
What hormone causes the formation of concentrated urine?
ADH (anti-diuretic hormone)
What hormone (via cAMP) causes rapid insertion of aquaporins to increase water permeability?
ADH (via the V2 receptor)
In the absence of ADH, collecting tubules and ducts are impermeable to water, preventing: ___________
Preventing absorption of water and loss to urine
What are aquaporins?
Aquaporins are a class of integral membrane proteins that form pores in the membrane of biological cells and selectively conduct water molecules in and out, while preventing the passage of ions and other solutes
What regulates ADH release?
1. Osmoreceptors in or near the hypothalamus
2. Barroreceptors: Carotid, aortic, & pulmonary regions sense/regulate synthesis/release.
What completes the negative feedback loop in the release of ADH?
Decreased stretch of barroreceptors stimulates release.

Atrial stretch receptors sense and also regulate release (increased stretch=decreased ADH)
What condition is associated with excess ADH secretion?
What condition is associated with too little ADH secretion?
What regulates oxytocin release?
1. Suckling
2. Dilation of the cervix and orgasm
What are the physiologic actions of prolactin?
Prolactin stimulates milk production and breast development.
What are the physiologic actions of inappropriate secretion of prolactin?
1. Galactorrhea
2. Failure to ovulate
3. Amenorrhea b/c it inhibits GnRH secretion
What is another name for GHRIH?
What are some sites of somatostatin synthesis and secretion?
1. Hypothalamus
2. Pancreas
3. Stomach
4. Intestines
What hormone from the liver is increased by GH?
Somatomedins (insulin-like growth factors, IGF)
Hyperpigmentation of Addison's disease is due to:
Low cortisol levelsstimulate ACTH secretion;
ACTH contains the MSH (melanocyte-stimulating hormone) fragment (so melanin is over-active = hyperpigmentation)
What are the major insulin counter regulatory hormones?
1. Somatostatin
2. Norepi
3. Epi
Explain paracrine effects in the pancreatic islet.
Glucagon stimulates insulin release and insulin inhibits glucagons. The alpha, beta, and delta cells are all in close proximity and stimulate or inhibit each other. The beta cells inhibit the alpha cells but the alpha cells stimulate the beta cells and the delta cells inhibit alpha and beta.
What are the enzymes responsible for catabolism of catecholamines?
What is VMA?
VMA is the final catabolic product of catecholomines and is formed via the following pathway:
1. NE forms Normetanephrine via COMT and Normetanephrine forms VMA via MAO.
2. EPI forms metanephrine via COMT and Metanephrine forms VMA via MAO
What are the physiologic effects of cortisol?
Cortisol stimulates insulin
What hormone stimulates gluconeogenesis?
Where does cortisol originate?
In the adrenal cortex
How does cortisol stimulate gluconeogenesis?
By increasing protein catabolism and increasing lipolysis.
What hormone decreases muscle mass, decreases bone formation, decreases connective tissue, modulates emotional tone and wakefulness, and increases glomerular filtration and free water clearance?
What are the immune effects of cortisol?
: Glucocorticoids induce the synthesis of lipocortin, an inhibitor of phospholipase A2 which inhibit the precursor to the inflammatory response, inhibit production of IL-2 and the proliferation of T lymphocytes;inhibit the release of histamine and serotonin from mast cells and platelets;suppresses the immune response.
What are the passive effects of cortisol?
Cortisol up regulates α1 receptors on arterioles, increasing their sensitivity to the vasoconstrictor effect of NE
What are the relationships between glucose homeostasis and GH?
GH increases insulin release. GH secretion is stimulated by hypoglycemia and decreased by hyperglycemia. So, it decreases glucose uptake into cells, increases lipolysis, and increases protein synthesis in muscle and increases lean body mass, and increases production of IGF.
What does a scatchard analysis measure?
The binding of hormone to a receptor.
What does radioimmunoassay measure?
Hormone concentrations
What are the major hormones regulating calcium homeostasis
1. PTH (parathyroid hormone)
2. Vitamin D
3. Calcitonin
What effects does PTH have on serum Ca/PO4 levels?
PTH increases Ca2+ serum levels and decreases PO4 serum levels
What is the active form of vitamin D?
What enzyme is induced by PTH necessary for active Vit.D. synthesis?
What is the stimulus for PTH release?
Low serum Ca2+ stimulates PTH secretion from the chief cells of the parathyroid gland.
What cells contain PTH receptors?
Bone, kidney, and intestines contain PTH receptors
What is osteocytic osteolysis?
Breakdown of bone
What are the effects of Vit. D on Ca/PO4 homeostasis?
Increases Ca2+ and PO4 in the intestine and in the kidney
What is calmodulin?
Calmodulin is calcium-binding protein. When calcium binds, physiologic actions
When adrenal steroids play a major role in sodium homeostasis?
What is the relationship between sodium and water balance?
Water follows sodium
What regulates the synthesis of aldosterone?
ACTH, the renin-angiotensin system, and potassium
What regulates the renin-angiotensin system?
Upright posture
Sodium deprivation
Decreased extracellular volume of blood
What is unique about ANP receptors?
1. Decreases ADH secretion
2. Can function in the hear
3. Uses the guanylate cyclase mechanism as a 2nd messenger
Aromatase converts: _______ to _______
testosterone to 17b-estradiol
5-alpha-reductase converts: ______ to _____
Testosterone to dihydrotestosterone (DHT)
Where is aromatase found?
In the granulose cells
What regulates the aromatase levels in the gonad?
What are the phases of the menstrual cycle?
1. Follicular Phase (days 1-14)
2. Ovulation day (day 15)
3. Luteal phase (days 15-28)
4. Menses (days 1-4)
What hormones are produced by the corpus luteum?
Estrogen and Progesterone
What hormone is responsible for the increase in basal body temperature around ovulation?
Progesterone released by the corpus luteum after ovulation raises BBT.
What does nitric oxide work thru?
a G protein
What is DKA?
Diabetes ketoacidosis: Ketone bodies produced as a result of insulin deficiency and it exceeds the bodies capacity to clear.
What are the ketoacids produced in DKA?
Acetoacetic acid, β-hydroxy butyrate, and acetone
What is meant by insulin resistance?
Insulin is unable to act on receptors in the body.
What does Graves disease result from?
High concentrations of thyroid stimulating immunoglobulins
What hormone dominates during the secretory phase?
What is the primary form of estrogen found in menopausal females?
What causes thinning of the cervical mucus?
What causes a thick cervical mucus plug?