Adrenal-pituitary implication for maintenance of tissue glycogen stores in cyclic and pregnant rats

Abstract

The influence of adrenal steroidogenesis upon glycogen storage during pregnancy and oestrous cycle in rats was studied. Adrenal steroids were totally supressed or inactivated by adrenalectomy or hypophysectomy of the cyclic as well as pregnant animals. The variations in glycogen reserves of heart, uterus and liver which take place during normal pregnancy were recorded from day 14 post-coitum to 24 h post-parturition. Uterine glycogen increased markedly from day 18 to the time of delivery. On the other hand hepatic glycogen decreased during 18 and 21 days of gestation. The effects of adrenalectomy and hypophysectonay during pro-oestrous phase of the oestrous cycle were qualitatively different from those of pregnant animals. Both surgical ablations increase uterine glycogen in pregnant females but similar treatment to rats in pro-oestrous phase of the cycle declined glycogen content of the uterus. The administration of compensatory doses of cortisol to adrenalectomized females or ACTH to hypophysectomized animals produced important alterations in glycogen stores of all the three organs studied. Cortisol administration to adrenalectomized females in pro-oestrous phase greatly increased uterine and cardiac glycogen whereas similar treatment to pregnant adrenalectomized rats showed marked increase only in the heart. ACTH treatment increased hepatic and cardiac glycogen in rats hypophysectomized during the cycle but the pregnant females subjected to ACTH administration showed increase only in the heart but liver glycogen declined. The compensatory treatment of adrenal and pituitary hormones to pregnant and cyclic animals provides evidence in support of the hypothesis that these hormones have an important role for the regulation of carbohydrate metabolism in heart, uterus and liver not only during normal life but also during pregnancy and oestrous cycle.