Studies on metabolism of vitamin A. The effect of vitamin A status on the secretion rates of some steroids into the ovarianvenous blood of pregnant rats

Abstract

1. Rats raised on a vitamin A-deficient diet supplemented with either retinyl acetate or retinoic acid were mated and became pregnant. 2. The rates of secretion of progesterone, 20α-hydroxypregn-4-en-3-one, oestradiol-17β and oestrone into the ovarian-venous blood of rats in these two groups were measured on days 9 and 15 of pregnancy. 3. Rates of secretion of progesterone and 20α-hydroxypregn-4-en-3-one, both on days 9 and 15, were lower for the rats given retinoic acid. No such differences were found in ovarian oestrogen secretion. 4. The implications of these results are discussed in the light of the previous demonstration that the activity of ovarian 3β-hydroxy-Δ5-steroid dehydrogenase was markedly less in pregnant rats given retinoic acid.