ABSTRACT
Forty ewes were given intramuscular injections of testosterone cypionate (200 mg) on each of the 20th, 27th and 40th days of gestation. This treatment ensured foetal exposure to testosterone from day 20 to day 65. Forty untreated ewes acted as controls. At birth, pre-natally androgenised male lambs were anatomically normal, but similarly treated female offspring displayed complete external genital masculinisation including the presence of a prepuce, penis and scrotum and the absence of an external vulval opening. No male gonads were present. Internally, the female lambs possessed ovaries, uteri, cervices and vagina of normal appearance. Two-weekly blood plasma samples were withdrawn from 10 androgenised and 6 control female offspring and 8 androgenised and 8 control male offspring from 4–30 weeks of age. Testosterone levels in males and LH levels in males and females were measured by radioimmunoassays. Analyses of variance showed that post-natal plasma LH levels in pre-natally androgenised lambs (male and female) were significantly depressed (P < 0.001), and that plasma testosterone concentrations in pre-natally androgenised males were subsequently depressed (P < 0.001). These results suggested that pre-natal androgenisation impaired hypothalamic hypophysiotrophic and/or pituitary function during the first 30 weeks of post-natal life which resulted either directly, or indirectly via reduced LH output, in a suppression of testosterone production by the testes.
Sexual Differentiation of Social Play and Copulatory Behavior in Prenatally Stressed Male and Female Offspring of the Rat
