title: Cytoplasmic and nuclear metabolism of testosterone in the brains of neonatal and prepubertal rats.
abstract: The metabolism of testosterone (T) in neonatal rat brains was measured following in vivo and in vitro incubations with 3H-testosterone.Steroids associated with nuclear and cytoplasmic fractions of brain tissue from 4, 12, and 32-day-old male and female rats were identified. Although there are quantitative differences under different methods of incubation, in all cases more than 95% of the radioactivity was recovered and identified as T, or the 5alpha-reduced metabolities, DHT and 3alpha-androstanediol. Most of the metabolism of T occurred in the cytoplasm but 5alpha-reduced metabolities were also associated with purified nuclei. Reaction kinetics indicate that the metabolic sequence is T leads to DHT leads to 3alpha DIOL. DHT levels were similar in the cytoplasmic fractions from the neonates (4 and 12-day-old animals) and prepubertal animals (32-day-old animals), but 3alpha-androstanediol was significantly reduced in these fractions from prepubertal animals compared to those from neonates. Sex differences in the metabolism of T in the various subcellular fractions were not detectable.
mesh_terms: D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D005260:Female; D007700:Kinetics; D008297:Male; D051381:Rats; D012737:Sex Factors; D012741:Sexual Maturation; D013739:Testosterone / Q000378:metabolism*
chemical_list: D013739:Testosterone