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- In the normal animal growth hormone releasing hormone (GHRH) is produced by the hypothalamus and stimulates the anterior pituitary to produce GH.
- Growth hormone has a catabolic effect on tissues via antagonism of insulin actions but also stimulates hepatic production of insulin like growth factor (IGF) which has anabolic actions including protein synthesis.
- IGF has a negative feedback effect on the hypothalamus and the anterior pituitary to reduce further GH production.
- Increasing concentration of GH also reduces hypothalamic stimulation of the anterior pituitary for further GH production.
- Pituitary dwarfs Congenital panhypopituitarism occur as a result of failure of GH production from the pituitary - as a result of hypothalamic failure.
- These animals are unable to grow normally.