Morphological and quantitative study of the Leydig cells of pigs fed with anabolic doses of clenbuterol

The effects of clenbuterol administered at anabolic doses on the testicular interstitium were studied in 30 pigs allocated to three experimental groups. The diet of two groups was supplemented with clenbuterol (Clb) (1 ppm), but whereas in the Clb group the treatment was given until slaughter (treatment period: 3 months), in the Clb group the clenbuterol was withdrawn 2 weeks before slaughter (treatment period: 2.5 months): in the control group, the pigs were fed without clenbuterol. For histological procedures, a fractional sampling scheme was applied and routine techniques for light and transmission electron microscopy were used. The results of subjective morphology and morphometrics showed slight differences between the treated and the control groups. Conversely, the stereological results identified a prominent hyperplasia of the Leydig cells and ultrastructural analysis of these cells revealed a conspicuous increase in the organelles related to testosterone production, suggesting a functional activation of the interstitial cells in response to the clenbuterol treatment. (C) 2001 Harcourt Publishers Ltd.