EFFECT OF ESTROGEN, PROGESTERONE AND TESTOSTERONE ON THE INCORPORATION OF L-VALINE-1-C14 INTO PROTEIN OF THE RAT LIVER AND UTERUS.

Abstract

The influence of progesterone on the uptake of L-valine-1-C14 into the trichloroacetic acid precipitated protein of rat liver and rat uterus has been studied in normal and pregnant rats. Rats were treated 6 hr before experiments with combinations of estradiol, progesterone and in some instances testosterone. L-Valine-1-C14 was then injected into the tail vein, or liver and uterine slices were incubated with L-valine-1-C14. After trichloroacetic acid extraction and drying, aliquots were dissolved in hyamine hydroxide and counted in a scintillation counter. Hormonal administration was shown to affect the uterus uptake but not that of the liver. Theincreased uptake in the uterus after estrogen administration was depressed after the addition of progesterone. Testosterone had no effect. Liver and uterine slices from pregnant rats at 6 and 16 days of gestation were incubated with L-valine-1-C14. A significant increase (P < 0.01) was shown in the liver uptake of Lvaline-1-C14 between rats at 6 days and 16 days of gestation. The uteri similarly showed a significant (P < 0.005) increase in uptake. There is, therefore, an increasing influence of advancing pregnancy on the uptake of Lvaline-1-C14 in vitro into both liver and uterus. (Endocrinology74: 1, 1964)