Retardation of Spermiation Following Short-Term Treatment of Rats with Theobromine

Abstract

Groups of 4–6 Fü-albino rats were examined 24 h after 3 daily doses of 500 mg/kg bw of theobromine administered orally by gavage as well as 1, 2,4, 6, and 10 weeks after 5 daily doses. Controls received the standard solvent vehicle (SSV) only. A variety of parameters were assessed including body and organ weights, serum clinical chemistry, hematological parameters. epididy­mal sperm motility and LDH-X fraction in seminal plasma, serum gonadotro­pins and testosterone, and the morphology of various organs. Testes were perfused with 5% glutaraldehyde and semi-thin sections were evaluated. The most striking morphological observation was a retarded release of late sper­matids into the tubular lumen mainly 2 weeks post treatment. This partial dis­ruption of the rigid spermatogenic synchronization was not followed by sub­stantial germ cell death. The other parameters investigated remained rela­tively normal throughout the study. These observations suggest that theobro­mine at the dose tested rather selectively interferes with germ cell kinetics. Ser­toli cell toxicity could account for these early and subtle effects as well as for the late and severe effects of subchronic exposure of rats to theobromine as reported in the literature.