Endocrine disorders 1

Question 1

What hormones are released by the posterior pituitary (2)

Answer 1

antidiuretic hormone and oxytocin

Question 2

role of ADH (1)

Answer 2

enhances water reabsroption from the collecting ducts

Question 3

role of oxytocin (2)

Answer 3

controls ejection of milkk from lactating breast and initiates uterine contractions

Question 4

What stimulates growth hormone secretion (4)

Answer 4

1. stress, hypogylcemia
2. glucagon
3. some aa, e.g. arginine
4. drugs such as levodopa and clonidine

Question 5

secretion of GH releasing hormone, and therefore of GH is pulsatile, occuring about 7-8x a day, and is usually associated with… (3)

Answer 5

1. exercise
2. onset of deep sleep
3. in response to the falling plasma glucose about an hour after meals

Question 6

Action of GH is primarly mediated by ____.

Answer 6

IGFs

Question 7

Effect of GH on:
a. carbohydrate metabolism
b. fat metabolism
c. protein synth

Answer 7

Effect of GH on:
a. carbohydrate metabolism = GH antagonies the insulin-mediated cell uptake of glucose, and excess secretion may produce glucose intolerance
b. fat metabolism = lipolysis is stimulated, with a consequent increase in the concentration of circulating free fatty acids that will antagonizes insulin release and action
c. protein synth = GH stimulates aa uptake by cells.

Question 8

Besides enlarged hands, feet, jaw, heart… people with increased GH have predisposition to ____ and ____ and these lab findings (3) are increased

Answer 8

predisposition to multiple pre-malignant colon polyposis and hypertension.

Hyperphosphatemia, hypercalcemia, hypertriglycerideamia

Question 9

What test do we do if we suspect acromegaly?

Answer 9

glucose suppression test (OGTT)

Question 10

Failure to suppress glucose can suggest acromegaly or gigantism, but also ___ (5)

Answer 10

1. severe renal disease
2. severe liver disease
3. heroin addiction
4. levodopa
5. DM

Question 11

What parameter do we use to monitor acromegaly or treatment for it?

Answer 11

IGF-1

Question 12

What state (1) increases IGF-1, and what states (3) decrease it?

Answer 12

increase: pregnancy

decrease: DM, starvation, obesity

Question 13

How do you treat GH disorder?

Answer 13

1. surgery to remove adenoma
2. bromocriptine (dopamine receptor agonist)
3. or somatostatin analouge

Question 14

What finding of GH do we expect in healthy individuals after glucose intake?

Answer 14

In healthy individuals, plasma GH concentration would be suppressed to less than 1 mg/L by the glucose intake.

Question 15

Symotpms of GH deficiency: adults (3) and children (1)

Answer 15

adults: tiredness, CVD, dyslipidemia
children: short stature - birthweight can be normal, but rate growth subnormal

Question 16

How will deficiency of ADH present (2)?

Answer 16

diabetes insipidus: polyuria
syndrome of inappropriate ADH: hyponatremia

Question 17

List consequences of pituitary hormone deficiencies (4)

Answer 17

1. growth retardation in children: low GH; low TSH and thyroid horm.
2. secondary hypogonadism: low gonadotropin deficiency (amenorrhea, infertility, atrophy of secondary sexual characteristics, delayed puberty)
3. secondary adrenocortical hypofunction (ACTH def)

Question 18

What tests do we order for suspected hypopituitarism? (4)

Answer 18

Plasma concetrations of:
1. sex hormones: LH, FSH, estradiol (female) and testosterone (male)
2. thyroid: total or free T4 and TSH
3. prolactin (to test for hypothalamic or pituitary stalk involevemnt)
4. cortisol at 9am to assess the risk of adrenocortical insufficiency

Question 19

Insulin test stimulation indications (3)

Answer 19

1. assess GH in growth deficiency
2. assess ACTH/cortisol reserve
3. differentiation of Cushingßs syndrome vs pseudoCushingßs syndrome

Question 20

Insulin test stimulation contraindications (5)

Answer 20

1. elderly
2. ischemic heart disease
3. epilepsy
4. pts who have cortisol < 100nmol/L at 9am
5. severe panhypopituitarism

Question 21

How do we differentiate Cushings syndrome vs pseudoCushing

Answer 21

In Cushing’s syndrome, neither plasma cortisol nor GH concentrations rise significantly after insulin stimulation test, although they usually do in cases of pseudo-Cushing’s syndrome

Question 22

What test do we do if insulin hypoglycemic test is contraindicated?

Answer 22

glucagon stimulation test of the hypothalamus-pituitary axis