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 group s. The diet of two groups was supplemented with clenbuterol (Clb) (1 ppm), but whereas in the Clb group the treatment was given until slaughter (treat ment period: 3 months), in the Clb group the clenbuterol was withdrawn 2 we eks before slaughter (treatment period: 2.5 months): in the control group, the pigs were fed without clenbuterol. For histological procedures, a fract ional sampling scheme was applied and routine techniques for light and tran smission electron microscopy were used. The results of subjective morpholog y and morphometrics showed slight differences between the treated and the c ontrol groups. Conversely, the stereological results identified a prominent hyperplasia of the Leydig cells and ultrastructural analysis of these cell s revealed a conspicuous increase in the organelles related to testosterone production, suggesting a functional activation of the interstitial cells i n response to the clenbuterol treatment. (C) 2001 Harcourt Publishers Ltd.