DYNAMICS OF HEPATIC GLYCOGEN: OESTROGEN AND PREGNANCY

Abstract

ABSTRACT The effects of oestradiol (0.5 μ/rat/day) given for a variable period on rat liver were investigated, and the results were compared with those of untreated pregnant rats at different stages of pregnancy. The part played by the adrenal under these conditions was also investigated. Oestrogen treatment for 14 and 21 days in intact rats reduced the liver glycogen. A corresponding reduction in food intake was noted during these days. However, a rebound rise in liver glycogen occurred after 28 days of oestrogen administration. In contrast, the ovariectomized animals did not show any change in liver glycogen following steroid treatment. During pregnancy the total liver glycogen increased after the first week, but returned to the normal level on day twenty one. The adrenal and serum cholesterol levels in oestrogen treated and pregnant rats remained low except for an increase in serum cholesterol on day 21 of gestation and 7 days after oestrogen treatment. The study suggests that continued oestrogen treatment of non-pregnant rats probably maintains some endogenous factor(s) (progesterone) for about 21 days, which antagonizes the effect of oestrogen administration on hepatic glycogen deposition. The implications of liver glycogen changes during pregnancy in relation to progesterone levels and dietary intake are discussed.