ENDOCRINE EFFECTS ON THE HEPARIN-INDUCED LIPEMIA CLEARING ACTIVITY (LCA) OF RAT PLASMA

Abstract

A study was made of the relationships of gonads, adrenal, and thyroid to the "lipemia-clearing activity" (LCA) which appears in rat plasma followed by heparin injection. Strong evidence was obtained that induction of LCA by heparin is controlled by the estrogenic secretion of the female gonad: estradiol inhibited LCA; mature females displayed less LCA than mature males, the sex difference being absent in immature animals; ovariectomy and hypophysectomy accelerated LCA; anterior pituitary extracts inhibited it in the female but not in the male; progesterone, testosterone, and orchidectomy had no effect. Adrenal-LCA relationships were complex: adrenalectomy accelerated LCA but the effects of injected steroids depended on the dosage level and on the duration of the treatment. Short lasting injections of small amounts of glucocorticoids inhibited LCA, the effect disappearing upon prolongation of treatment. By contrast, massive amounts of glucocorticoids accelerated LCA, whether given for a short or a long period of time. Chronic stress and ACTH had no effect, despite the induction of pronounced adrenal enlargement. Injected thyroxine inhibited LCA but surgical thyroidectomy did not affect it.