Pituitary Hormones

Question 1

PTH Action

Answer 1

Increase serum Ca Lower Phos. Bone resorption, intermittent PTH bone growth

Bone: Osteoblast release RANKL –> Activate Osteoclast –> Ca/Phos release. Osteoblast maturation. Increase osteocyte osteolysis

Kidney: Increase Ca reabsorption, Lower phos reabs. Activate 1 hydroxylase–> Increase 1, 25 OH.

Question 2

PTH Regulation

Answer 2

Low serum Ca
High serum Phos
Low serum Mg (super low Mg decrease PTH secretion)

Question 3

1,25 OH Action

Answer 3

Increase serum Ca and Phos

GI/Kidney: Increase Ca/phos resorption. Increase Calbindin (Inhibited by cortisol)

Bone: Osteoblast release RANKL –> Activate Osteoclast –> Ca/phos release. Osteoblast maturation

Question 4

1,25 OH Regulation

Answer 4

Increase
High PTH--> Activate 1 hydroxylase, deact 24 hydrox
Low Phos (same mech as PTH)
Low Calcium
Decrease
1,25 OH negative feedback 1 hydroxylase

Question 5

T3 Action

Answer 5

4 B’s: Brain Maturation, Bone growth, Beta adrenergic effects, Increase basal metabolic rate

Bone growth synergy with GH
Increase B1 receptors heart (High CO, HR, SV, contract)
Increase BMR via increase Na/K/atpase
Increase glycogenolysis, gluconeogenesis, lipolysis

Question 6

T3 regulation

Answer 6

Increase:
TRH–>TSH–>T3
Decrease:
T4 negative feedback on AP and hypothalamus

Question 7

Cortisol Action

Answer 7

A BIG FIB
Increase (Appetite, BP, Insulin Resistance, Gluconeogenesis, lipolysis, proteolysis) Decrease (Fibroblast act, Inflammation/immune, Bone formation)

BP: Increase a1 receptors (permissive action). High levels can bind aldosterone receptors

Insulin: Increase a2 receptors b islet cells

Inflammation: Inhibit leukotriene/PG synth. Inhibit WBC adhesion, Block H release mast cells, Block IL-2 prod

Bone: Decrease osteoblast activity

Question 8

Cortisol Regulation

Answer 8

Increase:
CRH–> ACTH release–> Cortisol
Decrease:
Cortisol Blocks Hypo, AP, and cortisol secretion

Question 9

Growth hormone Action

Answer 9

Metabolic (getting materials):
Increase liver gluconeogenesis, AA uptake muscle, lipolysis

Growth:
In presence insulin, produce IGF-1 in Liver
Increase long bone/appositional growth, increase muscle mass

Question 10

Growth Hormone Regulation

Answer 10

Increase:
GHRH release in pulses, exercise, deep sleep, puberty, hypoglycemia
Decrease:
Glucose, somatostatin