Uptake and Retention of Sex Steroids by the Neonatal Rat Adrenal Gland

Abstract

The uptake of radioactivity in the adrenal glands of 5-day-old male and female rats was examined 2 h following injection of radiolabeled testosterone, R1881, diethylstilbestrol, or estradiol. The adrenals of both sexes had higher levels of radioactivity than blood after testosterone or synthetic androgen (R1881) injection. The adrenals of neither sex showed any significant accumulation of radioactivity, following ³H-estradiol injection. When, however, cytosol prepared from neonatal adrenal glands was incubated with 2 nM ³H-estradiol, and the incubate subjected to column chromatography on Sephadex G-100, radioactivity was eluted with the void volume; this peak was absent with the addition of 100-fold unlabeled estradiol to the incubation. The possible role of α-fetoprotein in preventing the in vivo uptake and retention of 17β-estradiol is discussed since ³H-diethylstilbestrol, an estrogen which has low affinity for this protein, was retained by the adrenals of male rats. It is concluded that estrogens or androgens can have a direct effect on the neonatal adrenal gland.