Disorders of the Anterior Pituitary Gland

Question 1

How is GH regulated?

Answer 1

Secretion is pulsatile; peak levels 1-4 hrs after onset of sleep; 70% produced during stage 3 & 4 sleep

Question 2

What physiologic factors affect GH secretion?

Answer 2

Increase= sleep, exercise, strees, postprandial hypoglycemia and hyperamoniacidemia; Decrease= Hyperglycemia

Question 3

What pathologic factors affect GH secretion?

Answer 3

Increase= protein depletion and starvation, anorexia, ectopic production of GHRH, chronic renal failure, and acromegaly; Decrease= obesity , hypo and hyperthyroidism

Question 4

What causes Pituitary Gigantism?

Answer 4

most common cause is GH-secreting pituitary adenoma

Question 5

What is the best screening test for pituitary gigantism and acromegaly?

Answer 5

Serum IGF-1 measurement; sensitive test and not dependent on time of day

Question 6

What is the treatment of choice for gigantism/acromegaly? What is the 1st line medication?

Answer 6

Transphenoidal surgery; cure rate for microadenomas is 85% and 50% for macroadenomas: 1st med after surgery are Somatostatin analogues

Question 7

What are the non-endocrine causes of Dwarfism?

Answer 7

Constitutional short stature, Genetics, intrauterine growth retardation, maternal drug/alcohol usage, genetic syndromes, Chronic disease, and Malnutrition