EFFECT OF NEONATAL ADMINISTRATION OF DIFFERENT ANDROGENS IN THE FEMALE RAT: CORRELATION BETWEEN AROMATIZATION AND THE INDUCTION OF STERILIZATION

Abstract

SUMMARY Groups of neonatal female rats were treated once daily for the first 5 days of life with oil, 1 μg testosterone propionate, or 10 μg of one of the following androgens; androstenedione-enol-propionate, 19-hydroxytestosterone propionate, 5α-dihydrotestosterone propionate, 5α-androstanedioneenol-propionate, androsterone propionate, 5α,3α-androstenediol dipropionate, 5α,3β-androstanediol dipropionate. A final group was given 100 μg 5α,3β-androstanediol dipropionate as a single injection on day 1 of life. Only those androgens which are aromatizable were effective in preventing cyclicity whilst the 5α-reduced androgens were ineffective or only partially effective. All treatments significantly increased the ano-genital distance compared with oil-treated control animals. There were no clear relationships between aromatization and the effects on suppressing sexual behaviour after oestrogen and progesterone treatment. The results are discussed in terms of the role of aromatization in the hormonal control of hypothalamic differentiation.