Watson--Endocrinology Study Guide

Front 1

What are the glycoproteins that are made up of alpha and beta units and have their biological activities resident in the beta subuint.

Back 1

TSH
FSH
LH

Front 2

What types of hormones typically bind to receptor in/on the cell surface?

Back 2

Protein, peptide, and catecholamine hormones

Front 3

What types of hormones typically bind to receptor inthe cell cytoplasm?

Back 3

Steroid hormones

Front 4

What types of hormones typically bind to receptor in the cell nucleus?

Back 4

Thyroid hormones

Front 5

What is the action of the "Adenyl Cyclase-cAMP Second Messenger System?"

Back 5

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

Front 6

What are some of the hormones which utilize the Adenyl Cyclase-cAMP 2nd messenger system?

Back 6

ACTH
Angiotensin II
Calcitonin
Catecholamines
CRH
FSH
Glucagon
hCG
LH
PTH
Secretin
Somatostatin
TSH
Vasopressin (V2 receptor)

Front 7

What is the action of the Phospholipase C/IP3 Mechanism?

Back 7

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

Front 8

What are some of the hormones that utilize the IP3 second messenger system?

Back 8

GnRH, TRH, GHRH, Angiotensin II, ADH (V1), Oxytocin, alpha-r receptors

Front 9

What is the action of the Ca--calmodulin mechanism?

Back 9

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

Front 10

What does sTAR do?

Back 10

Transport cholesterol into the mitochondria

Front 11

What does 5-alpha-reductase do?

Back 11

Converts testosterone to DHT

Front 12

What does the SCC step do?

Back 12

Converts cholesterol to pregnenolone.

Front 13

What type of steroid is estrogen?

(C-18, C-19, or C-21?)

Back 13

C-18 steroid, which have estrogenic activity

Front 14

What type of steroid is DHEA?

(C-18, C-19, or C-21?)

Back 14

C-19; which has androgenic activity and precursors to the estrogens

Front 15

What type of steroid is androstenedione?

(C-18, C-19, or C-21?)

Back 15

C-19; which has androgenic activity and precursors to the estrogens

Front 16

What type of steroid is progesterone?

(C-18, C-19, or C-21?)

Back 16

C-21

Front 17

What does aromatase do?

Back 17

Converts testosterone to estradiol

Front 18

What type of steroid is deoxycoricosterone?

(C-18, C-19, or C-21?)

Back 18

C-21

Front 19

What type of steroid is aldosterone?

(C-18, C-19, or C-21?)

Back 19

C-21

Front 20

What type of steroid is cortisol?

(C-18, C-19, or C-21?)

Back 20

C-21

Front 21

What hormones can be derived from preproopiomelanocortin (POMC)?

Back 21

1. ACTH
2. Melanocyte-stimulating hormone (MSH)
3. Beta-endorphin
4. Beta-lipotropin

Front 22

Which anterior pituitary hormone is primarily regulated by an inhibitory factor from the hypothalamus, but is also released by TRH?

Back 22

Prolactin secretion is inhibited by dopamine.

Thyrotropin-releasing hormone (TRH) increase prolactin secretion.

Front 23

What are the major regulated in catecholamine synthesis?

Back 23

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)

Front 24

What is the rate-limiting step in catecholamine synthesis?

Back 24

The rate limiting step (conversion of tyrosine to L-Dopa) occurs in the presence of the enzyme tyrosine hydroxylase.

Front 25

What step in catecholamine synthesis is regulated by cortisol?

Back 25

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.

Front 26

What is the source of cholesterol for steroid secreting glands?

Back 26

LDL

Front 27

What is the rate limiting step in steroid synthesis?

Back 27

Rate limiting step is the side chain cleavage (SCC) step in the conversion of cholesterol to pregnenolone

Front 28

What are the zones of the adrenal gland?

Back 28

1. Zona glomerulosa (outermost)
2. Zona fasciculata (middle)
3. Zona reticularis (innermost)

Front 29

What hormones are associated with Zona glomerulosa?

Back 29

Aldosterone (mineralocorticoid)

Front 30

What hormones are associated with Zona fasciculata?

Back 30

Glucocorticoids/cortisol and corticosterone

Front 31

What hormones are associated with Zona reticularis?

Back 31

Androgens (sex steroids) and DHEA

Front 32

What are the effects of a 21OHlase deficiency?

Back 32

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

Front 33

What are the effects of a 21OHlase deficiency?

Back 33

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)

Front 34

What are the androgens of the adrenal gland?

Back 34

DHEA and androstenedione

Front 35

What is the 17KS (ketosteroid assay)

Back 35

The 17KS assay measures the amount of 17KS androgens present (remember: the 17-KS are DHEA and androstenedione)

Front 36

What are the major steroids of the gonads?

Back 36

Testosterone, Estrogen, Progesterone

Front 37

What is meant by down-regulation?

Back 37

A hormone decreased the number or affinity of receptors for itself or for another hormone

Front 38

What is meant by up-reguation?

Back 38

A hormone increases the number or affinity of receptors for itself or for another hormone

Front 39

What hormones are released from the posterior pituitary?

Back 39

ADH (or vassopressin) and Oxytocin

Front 40

What hormone causes the formation of concentrated urine?

Back 40

ADH (anti-diuretic hormone)

Front 41

What hormone (via cAMP) causes rapid insertion of aquaporins to increase water permeability?

Back 41

ADH (via the V2 receptor)

Front 42

In the absence of ADH, collecting tubules and ducts are impermeable to water, preventing: ___________

Back 42

Preventing absorption of water and loss to urine

Front 43

What are aquaporins?

Back 43

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

Front 44

What regulates ADH release?

Back 44

1. Osmoreceptors in or near the hypothalamus
2. Barroreceptors: Carotid, aortic, & pulmonary regions sense/regulate synthesis/release.

Front 45

What completes the negative feedback loop in the release of ADH?

Back 45

Decreased stretch of barroreceptors stimulates release.

Atrial stretch receptors sense and also regulate release (increased stretch=decreased ADH)

Front 46

What condition is associated with excess ADH secretion?

Back 46

Dehydration

Front 47

What condition is associated with too little ADH secretion?

Back 47

Diabetes

Front 48

What regulates oxytocin release?

Back 48

1. Suckling
2. Dilation of the cervix and orgasm

Front 49

What are the physiologic actions of prolactin?

Back 49

Prolactin stimulates milk production and breast development.

Front 50

What are the physiologic actions of inappropriate secretion of prolactin?

Back 50

1. Galactorrhea
2. Failure to ovulate
3. Amenorrhea b/c it inhibits GnRH secretion

Front 51

What is another name for GHRIH?

Back 51

Somatostatin

Front 52

What are some sites of somatostatin synthesis and secretion?

Back 52

1. Hypothalamus
2. Pancreas
3. Stomach
4. Intestines

Front 53

What hormone from the liver is increased by GH?

Back 53

Somatomedins (insulin-like growth factors, IGF)

Front 54

Hyperpigmentation of Addison's disease is due to:

Back 54

Low cortisol levelsstimulate ACTH secretion;
ACTH contains the MSH (melanocyte-stimulating hormone) fragment (so melanin is over-active = hyperpigmentation)

Front 55

What are the major insulin counter regulatory hormones?

Back 55

1. Somatostatin
2. Norepi
3. Epi
4. GHIH

Front 56

Explain paracrine effects in the pancreatic islet.

Back 56

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.

Front 57

What are the enzymes responsible for catabolism of catecholamines?

Back 57

COMT and MAO

Front 58

What is VMA?

Back 58

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

Front 59

What are the physiologic effects of cortisol?

Back 59

Cortisol stimulates insulin

Front 60

What hormone stimulates gluconeogenesis?

Back 60

Cortisol

Front 61

Where does cortisol originate?

Back 61

In the adrenal cortex

Front 62

How does cortisol stimulate gluconeogenesis?

Back 62

By increasing protein catabolism and increasing lipolysis.

Front 63

What hormone decreases muscle mass, decreases bone formation, decreases connective tissue, modulates emotional tone and wakefulness, and increases glomerular filtration and free water clearance?

Back 63

Cortisol

Front 64

What are the immune effects of cortisol?

Back 64

: 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.

Front 65

What are the passive effects of cortisol?

Back 65

Cortisol up regulates α1 receptors on arterioles, increasing their sensitivity to the vasoconstrictor effect of NE

Front 66

What are the relationships between glucose homeostasis and GH?

Back 66

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.

Front 67

What does a scatchard analysis measure?

Back 67

The binding of hormone to a receptor.

Front 68

What does radioimmunoassay measure?

Back 68

Hormone concentrations

Front 69

What are the major hormones regulating calcium homeostasis

Back 69

1. PTH (parathyroid hormone)
2. Vitamin D
3. Calcitonin

Front 70

What effects does PTH have on serum Ca/PO4 levels?

Back 70

PTH increases Ca2+ serum levels and decreases PO4 serum levels

Front 71

What is the active form of vitamin D?

Back 71

1,25-dihydroxycholecalciferol

Front 72

What enzyme is induced by PTH necessary for active Vit.D. synthesis?

Back 72

1-alpha-hydroxylase

Front 73

What is the stimulus for PTH release?

Back 73

Low serum Ca2+ stimulates PTH secretion from the chief cells of the parathyroid gland.

Front 74

What cells contain PTH receptors?

Back 74

Bone, kidney, and intestines contain PTH receptors

Front 75

What is osteocytic osteolysis?

Back 75

Breakdown of bone

Front 76

What are the effects of Vit. D on Ca/PO4 homeostasis?

Back 76

Increases Ca2+ and PO4 in the intestine and in the kidney

Front 77

What is calmodulin?

Back 77

Calmodulin is calcium-binding protein. When calcium binds, physiologic actions

Front 78

When adrenal steroids play a major role in sodium homeostasis?

Back 78

Aldosterone

Front 79

What is the relationship between sodium and water balance?

Back 79

Water follows sodium

Front 80

What regulates the synthesis of aldosterone?

Back 80

ACTH, the renin-angiotensin system, and potassium

Front 81

What regulates the renin-angiotensin system?

Back 81

Hemorrhage
Upright posture
Sodium deprivation
Decreased extracellular volume of blood

Front 82

What is unique about ANP receptors?

Back 82

1. Decreases ADH secretion
2. Can function in the hear
3. Uses the guanylate cyclase mechanism as a 2nd messenger

Front 83

Aromatase converts: _______ to _______

Back 83

testosterone to 17b-estradiol

Front 84

5-alpha-reductase converts: ______ to _____

Back 84

Testosterone to dihydrotestosterone (DHT)

Front 85

Where is aromatase found?

Back 85

In the granulose cells

Front 86

What regulates the aromatase levels in the gonad?

Back 86

FSH

Front 87

What are the phases of the menstrual cycle?

Back 87

1. Follicular Phase (days 1-14)
2. Ovulation day (day 15)
3. Luteal phase (days 15-28)
4. Menses (days 1-4)

Front 88

What hormones are produced by the corpus luteum?

Back 88

Estrogen and Progesterone

Front 89

What hormone is responsible for the increase in basal body temperature around ovulation?

Back 89

Progesterone released by the corpus luteum after ovulation raises BBT.

Front 90

What does nitric oxide work thru?

Back 90

a G protein

Front 91

What is DKA?

Back 91

Diabetes ketoacidosis: Ketone bodies produced as a result of insulin deficiency and it exceeds the bodies capacity to clear.

Front 92

What are the ketoacids produced in DKA?

Back 92

Acetoacetic acid, β-hydroxy butyrate, and acetone

Front 93

What is meant by insulin resistance?

Back 93

Insulin is unable to act on receptors in the body.

Front 94

What does Graves disease result from?

Back 94

High concentrations of thyroid stimulating immunoglobulins

Front 95

What hormone dominates during the secretory phase?

Back 95

Progesterone

Front 96

What is the primary form of estrogen found in menopausal females?

Back 96

Estrone

Front 97

What causes thinning of the cervical mucus?

Back 97

Estrogen

Front 98

What causes a thick cervical mucus plug?

Back 98

Progesterone