Search

The uptake of radioactivity by the reproductive organs and livers of neonatal, prepuberal, puberal and adult male and female rats 1 h after intraperitoneal administration of 3H-testosterone was measured by liquid scintillation quantification. Tissue homogenates of the testes, vasa deferentia-epididymides, ovaries, uteri, livers, muscle, cerebrum and thymuses were fractionated and aqueous, lipid and protein-nucleoprotein fractions separated for analysis. Accumulation of radioactivity above control levels was found in all fractions of the tissues, particularly in the fractions containing the protein-nucleoprotein residues of the reproductive organs and livers. The radioactivities associated with the tissue residues of reproductive organs were highest during the first postnatal days and subsequently declined while the radioactivities associated with the livers were lowest 2 days after birth and increased markedly by day 10. These observations suggest that the alterations in sexual physiology and behavior observed in adult female rats subsequent to administration of androgens during their neonatal critical period of sex development may be due to immaturity of steroid degradative mechanisms in the neonatal liver.