GH and prolactin

Growth hormone acts indirectly on cartilage and bone by?

causing mainly the Liver and other tissue to form proteins called Somatomedins (A&B&C)

Somatomedins

polypeptide growth factors

the function of Somatomedins

stimulates the proliferation of epiphyseal cartilage, and stimulates osteoblast activity

At the end of adolescence

the epiphyseal plate completely ossify, or "close , ✓ thickness X length

Effect on protein

increases transport of amino acid to interior of the cell

,stimulates the transcription of DNA,

direct effect on ribosomes,

decreases catabolism

Effect on fat

increases utilization of fat

enhances conversion of fatty acids to acetyl-Co A For energy

Effect on Carbohydrates

decreases utilization of glucose

decreases number of insulin receptors

increases glycogen deposition

Other functions:

stimulates erythropoiesis .

increases intestinal absorption of calcium, and maintains phosphorus balance.

decreases urinary excretion of sodium and potassium

for the growing tissue.

reasons lead to increase GH

hypoglycemia

decreased blood level of free fatty acids

increased blood level of certain amino acids (as arginine)

deep sleep

stress

Deficiency during childhood:

Dwarfism

Manifestations:

(1) Short stature:

(2) Decreased metabolic rate

(3) No manifestations of thyroid deficiency or adrenocortical deficiency

Dwarfism

1/3 of patients, the deficiency is of GH alone. These Individuals mature sexually

Deficiency in adulthood:

(A) Partial pituitary insufficiency:

or

(B) Complete pituitary insufficiency: (panhypopituitarism)

(A) Partial pituitary insufficiency:

- The first function to be impaired is the secretion of GH.

(B) Complete pituitary insufficiency: (panhypopituitarism)

- This is a generalized failure of anterior pituitary gland

Effects of hypersecretion of prolactin

(1) Galactorrhea (2) Amenorrhea