Biochemical effects of neonatal testosterone treatment on the female rat hypothalmus during postnatal development. I. DNA synthesis.

The effect of 1 mg testosterone propionate (TP) administered on the 2nd day of life was studied on DNA synthesis in the anterior and posterior pats of the hypothalamus, in the forebrain, anterior pituitary and liver in 5, 7, 14 and 21 days old female rats. As an index of DNA synthesis the rate of 2-14C-thymidine (40 muCi/100 g body weight) incorporation into DNA was measured 1 hr after a subcutaneous injection . As an effect of TP treatment in both hypothalamic regions the rate of thymidine incorporation into DNA, markedly decreased during the first two weeks of life, while at 21 days no difference from the control value was found. In the anterior pituitary too therate of DNA synthesis decreased at 5 and 7 days but at 14 and 21 days the values were similar to the controls. TP treatment had no effect on the rate of DNA synthesis in the forebrain or in the liver.