Endocrinology

Question 1

6 hormones produced by anterior pituitary and their effector organ

Answer 1

Question 2

List the hypothalamic hormones and their chemical nature

Answer 2

Question 3

Describe conditions associated with hypersecretion of growth hormone and treatment

Answer 3

Treatment: D2 agonist and long acting somatostatin analogues; to cause negative feedback.

Question 4

Describe conditions associated with hyposecretion of growth hormone and treatment

Answer 4

Treatment with recombinant hGH (growth hormone) or hIGF-1 (growth factor)

Question 5

Describe the hormones produced in the posterior pituitary and their function

Question 6

Describe the synthesis of thyroid hormones and factors which control the pathway

Answer 6

Question 7

Describe the process involved in the release and plasma transport of thyroid hormones

Answer 7

Majority of T3 and T4 is transported by thyroxine binding globulin (TBG), then albumin then tyrosine binding pre globulin (TBPA).

Question 8

Physiological actions on thyroid hormones:

O2 consumption, cardiac muscle, sensitivity to catecholamines, gut motility, erythropoietin, bone turnover, cholesterol degradation, metabolic turnover.

Answer 8

Question 9

Define goitre and reasons for its formation, and what goitrogens are.

Answer 9

Growth of the thyroid gland due to hyperplasia and hypertrophy (cell growth and division). Occurs in hypothyroidism and hyperthyroidism.

Goitrogens (substances that increase goitre) include iodine, cassava, lithium, some tap water, cough mixtures.

Question 10

Causes of Goitre

Answer 10

Goitrogens - things that supress thyroid hormone secretion and increase TSH secretion.

excess iodine, cabbage, cassava, lithium,

Question 11

What is plasma conc. of cortisol and what does it bind to in the blood.

Answer 11

13.9 ug/dL

75% binds to corticosteroid binding globulin (CBG)

15% binds to albumin

10% is free

Question 12

How is aldosterone transported in the body and what percent of each.

Answer 12

40% Free

20% corticosteriod binding globulin (CBG)

40% albumin

Question 13

Mechanism of action of steroid hormones on cells

Answer 13

1. hormone enters cell by diffusion
2. binds to cytoplasmic receptor
3. Dissociation of hsp90
4. Hormone receptor complex dimerizes
5. complex binds to HRE on DNA
6. increase mRNA production

Question 14

Metabolic effects of cortisol

Answer 14

Decreased cell glucose uptake and use, increased gluconeogenesis (higher blood sugar).

Decreases bone formation (osteoporosis)

Protein breakdown (muscle wasting)

Supress immune system & inflammation

Increased water retension

Decreases healing

Question 15

role of 11beta- hydroxysteroid dehydrogenase (11b- HSD)

type 1

type 2

Answer 15

Type 1: converts coritsone to cortisol in liver, adipose and muscle tissue (activating it’s effect)

Type 2: converts cortisol to cortisone in aldosterone sensitive tissue (inhibiting effect of cortisol). It prevents the binding of cortisol to mineralocorticoids.

Question 16

One condition related to glucogorticoids

Answer 16

Iatrogenic cushing’s syndrome

Question 17

define mineralocorticoids and give 2 examples.

Answer 17

Aldosterone and spironolactone.

Aldosterone effects: increases water retention by increasing Na/ k exchange and increasing amount of ENaC Channels.

Spironolactone: Aldosterone antagonist.