netter180

Actions of Insulin

ENDOCRINE PHYSIOLOGY

Figurę 8.20 Actions of Insulin-

Insulin is a fueł-storage hormone. The major fuels used by cells are glucose, (alty acids, and keto acids (derived during fatty acid metabolism). Some cells preferentially use glucose as Ibeir lud {e.g.. neurons). whereas other cells preferentially use fatty acids (e.g., skeletal muscle). Keto acids can be used by many cells when glucose and fatty acids are not readily available (e.g., fastingj. Insulin stimu lates the uptake of glucose into cells, where it is stored in the form of glycogen (espedaily in the liver and skelelal muscle). It also stimu-lates fat synthesis and inhibits lipolysis, thus stonng fatty acids as triglycerides (fatty acid metabolism to keto acids is also inhihited). Finally, insulin stimulates the uptake ot amino acids into cells and their storage as protein. The net effect is that blood levels of glucose and keto acids decrease.

199