Lipolytic Activity of Rat Pituitaries In Vitro

Abstract

Rat anterior pituitaries when coincubated with isolated rat epididymal fat cells showed lipolytic activity as measured by the release of glycerol into the incubation medium. Lipolytic activity of pituitary glands significantly increased when the glands of adrenalectomized animals were used. Thyroidectomy and/or gonadectomy has no effect. Arginine-vasopressin stimulated the lipolytic activity of pituitary glands. Dexamethasone, when present in the incubations, did not inhibit the vasopressin stimulated lipolytic activity of pituitary glands but the pretreatment of rats with dexamethasone abolished completely its action. When the pituitary glands of fasted rats were incubated with isolated epididymal fat cells, the presence of dexamethasone stimulated the lipolysis. This action of dexamethasone was blocked by cycloheximide. The results seem to indicate that the lipolysis caused by rat pituitary glands in vitro in rat isolated fat cells is probably due at least to ACTH and growth hormone.

Key words

Fat Cells - Pituitary Glands - Lipolysis - Rat