Hypothalamic Pituitary Relationships

Question 1

Primary (1) endocrine disorder causes high or low levels of a hormone due to a defect in the ___________________.

Answer 1

Peripheral endocrine gland

Question 2

Secondary (2) endocrine disorder causes high or low levels of a hormone due to a defect in the ___________________.

Answer 2

Pituitary gland

Question 3

Tertiary (3) endocrine disorder causes high or low levels of a hormone due to a defect in the ___________________.

Answer 3

Hypothalamus

Question 4

What releases ACTH?

Answer 4

Corticotroph

Question 5

What releases TSH?

Answer 5

Thyrotroph

Question 6

What releases FSH + LH?

Answer 6

Gonadotroph

Question 7

What releases GH?

Answer 7

Somatotroph

Question 8

What releases prolactin?

Answer 8

Lactotroph

Question 9

What disease is caused by prolonged, excessive secretion of growth hormone (GH) in adult life AFTER PUBERTY?

Answer 9

Acromegaly

Excessive growth of soft tissue, gradual, loss of visual field, large hands + feet, prominent lower jaw, cardiomegaly

increased organ size, increased periosteal bone growth, increased extremeties size

Question 10

What mediates the actions of growth hormone?

Answer 10

Somatomedin C (IGF-1)

Question 11

In acromegaly, why do we measure IGF-1 initially and not growth hormone?

Answer 11

GH levels flucuate, but IGF-1 levels remain constant

Question 12

Besides measuring IGF-1 levels, what is the second test preformed to diagnose acromegaly?

Answer 12

Give them glucose (oral glucose tolerance test OGTT), and if there is inadequate suppression of GH this confirms acromegaly. Also, you might see a pituitary mass seen on a brain MRI.

Question 13

How is growth hormone secreted?

Answer 13

In a pulsatile manner

Question 14

What causes a growth hormone deficiency?

Answer 14

Decreased secretion of GHRH in hypothalamus

Can’t generate somatomedins

GH resistence

Question 15

What causes gigantism?

Answer 15

A growth hormone secreting pituitary adenoma BEFORE PUBERTY

Question 16

What does GH act on to stimulate bone growth?

Answer 16

Chrondrocytes

Question 17

What are the 3 metabolic functions of growth hormone?

Answer 17

1. Diabetogenic effect (increase in blood glucose conc.)
2. Increase in protein synthesis + organ growth
3. Increase in linear growth

Question 18

What happens to GH during a fast?

Answer 18

It should increase and Somatomedin + Insulin decrease

Question 19

What stimulates LH + FSH secretion?

Answer 19

GnRH

Question 20

What can prolactin inhibit?

Answer 20

GnRH

Question 21

How would you characterize a pituitary adenoma?

Answer 21

Benign + slow growing w/ hypersecretion

Question 22

What is the progression from pituitary adenoma –> Cushing’s disease?

Question 23

What is the progression from pituitary adenoma –> TSH - secreting tumor?

Question 24

What is the progression from pituitray adenoma –> Acromegaly + Gigantism

Question 25

What is the progression from pituitary adenoma –> Prolactinoma

Question 26

What is the progression from pituitary adenoma –> Non-functioning adenoma

Question 27

What causes Sheehan Syndrome?

Answer 27

Postpartum hypopituitarism from necrosis of the pituitary gland.

Hard to breast feed + amenorrhea (no period)

Question 28

What causes Central DI?

Answer 28

Decreased ADH

Treat w/ desmopressin (prevents water excretion)

Question 29

What causes nephrogenic DI?

Answer 29

Kidney’s can’t respond to ADH (so increased ADH)

NO TREATMENT

Question 30

How do you diagnose Diabetes Insipidus?

Answer 30

Water Deprivation test

If urine is still clear afterwards thats (+)

If no change w/ desmopressin –> nephrogenic

Question 31

Is plasma osmalarity increased or decreased in DI?

Answer 31

Increased (because you are peeing out all the water, since ADH retains water and you have no ADH)

Question 32

Is urine dilute or concentrated in SIADH?

Answer 32

Concentrated –> holding a lot of water in your body cause increased ADH secretion