Endocrine #1

Question 1

What hormones are released by the hypothalamus relating to growth?

Answer 1

Growth hormone regulating hormone (GHRH)

Somatostatin (SST)

Question 2

What effect does GH secretion have on GHRH secretion?

Answer 2

GH is a negative regulator of GHRH secretion

Question 3

Insulin-like Growth Factor 1 (ILGF-1)

Answer 3

Produced in the liver in response to GH
Negative regulator of GH
Positive stimulator of SST release

Question 4

JAK-STAT kinase activity

Answer 4

A receptor associated JAK kinase activity mediates the effect of GH

Question 5

Growth Hormone Physiology

Answer 5

Complex effects on growth and metabolism

Many effects are mediated through IGF-1

Question 6

Growth Hormone Theraputics

Answer 6

Treatment in children with short stature
Treatment of severe catabolic states (ie AIDS)
Anti-aging (benefits are controversial)
GH antagonists are used to treat acromegaly

Question 7

Where is Follicle Stimulating Hormone (FSH) released from?

Answer 7

Anterior Pituitary

Question 8

Where is Leutinizing hormone (LH) released from?

Answer 8

Anterior Pituitary

Question 9

Where is Human Chorionic Gonadotropin (hCG) released from?

Answer 9

Placenta

Question 10

FSH and LH receptors are what?

Answer 10

G protein coupled receptors linked to Gas

Question 11

What is FSH release related to in women?

Answer 11

Ovarian follicle development

Question 12

What is FSH and LH release related to in women?

Answer 12

Ovarian steroidogenesis

Question 13

What is LH release related to during the follicular stage of the menstrual cycle?

Answer 13

Androgen production

Question 14

What is FSH release related to during the follicular stage of the menstrual cycle?

Answer 14

Conversion of androgens to estrogens

Question 15

What is LH release related to during the luteal stage of the menstrual cycle?

Answer 15

Estrogen and progesterone production (if pregnancy does not occur)

Question 16

What is hCG release related to during the luteal stage of the menstrual cycle?

Answer 16

Estrogen and progesterone production if pregnancy occurs

Question 17

The coordinated pattern of FSH and LH secretion during the menstrual cycle required for what?

Answer 17

Follicle development, ovulation, and pregnancy

Question 18

What is FSH responsible for in men?

Answer 18

Spermatogensis

Question 19

What is LH responsible for in men?

Answer 19

Testosterone produciton

Question 20

FSH, LH, hCG theraputics

Answer 20

Used to induce ovulation that is secondary to hypogonadotrpic hypogonadism, polycystic ovary syndrome, obesity, and others
Complex protocols require close monitoring
Expensive
Used to treat male infertility in cases not treatable with androgen alone

Question 21

What hormones are released from the posterior pituitary?

Answer 21

Oxytocin

Vasopressin (aka ADH)

Question 22

What is the net effect of the release of vasopressin?

Answer 22

Vasoconstriction - increasing arterial blood pressure

Renal fluid reabsorption - increasing blood volume and arterial pressure

Question 23

What are the different receptors for vasopressin?

Answer 23

V1

V2

Question 24

V1 vasopressin receptors

Answer 24

G-protein coupled receptors
On vascular smooth muscle - mediates vasoconstriction
Linked to Gaq
Activation contracts vascular smooth muscle

Question 25

V2 vasopressin receptors

Answer 25

G-protein coupled receptors
On kidney tubules
Mediate water retention
Linked to Gas

Question 26

Clinical uses of vasopressin

Answer 26

Treatment of diabetes insipidous
Treatment of certain types of bleeding problems
Treatment of nocturnal enuresis (bed wetting)

Question 27

Clinical uses of vasopressin antagonists

Answer 27

Used to treat hyponatremia (low Na in the blood)
Very complex - almost counter-intuitive
Limit water retention

Question 28

Oxytocin

Answer 28

Works through G-protein coupled receptors (Gaq)
Induces contraction of uterine smooth muscle
Eliciys mile ejection in lactating women
“the love hormone” - because of its role in sexual arousal

Question 29

Oxytocin Physiology

Answer 29

Low dose - Increase frequency and force of contractions

High dose - Sustained contractions

Question 30

Oxytocin Theraputics

Answer 30

Induce labor - if early vaginal delivery required or labor problems
Atosiban - antagonist (of both vasopressin and oxytocin), used to halt premature labor

Question 31

Metabolic effects of thyroid hormone

Answer 31

Calorogenic effect - induces tolerance to cold and avaliability of ATP
Carbohydrate metabolism - increased glucose absorption from gut, glycogenolysis, gluconeogensis, and glucose oxidation
Lipid metabolism - lipogenesis in adipocytes, in coordination with blood glucose levels

Question 32

What is the significance of thyroid hormone and development

Answer 32

Effect on growth as manifested in growing children - TH stimulates GH secretion and promotes GH effects
Important in promoting growth and development of the brain during fetal and postnatal life - deficiency can lead to mental retardation

Question 33

Goiter

Answer 33

Enlargment of the thyroid gland

Question 34

What are causes of a goiter?

Answer 34

Iodine deficiency (leading cause but rare in N America)
Autoimmune disease where antibodies attack thyroid

Question 35

Treatment of a goiter

Answer 35

Not necessary unless the goiter is large enough and has symptoms (often no symptoms)
Surgery is rarely used and is reserved for cases that cause difficulty of swallowing or breathing

Question 36

Treatment for under-active thyroid

Answer 36

Synthetic thyroid hormone

T3, T4, or a combination of the two of them

Question 37

Treatment for over-active thyroid

Answer 37

Anti-thyroid drugs
Thioamides
Anion inhibitors
Iodide

Question 38

Which form of Thyroid hormone is dominant?

Answer 38

T4 is most abundant in plasma

T3 is the most active

Question 39

Thioamides

Answer 39

Block thyroid hormone synthesis

Question 40

Anion inhibitors

Answer 40

Block I- transport into the the thyroid

Question 41

Iodide

Answer 41

High concentrations inhibit transport and inhibit hormone biosynthesis