Variations of gossypol sensitivity in boar spermatozoal electron transport chain segments

The concentration effect of gossypol on hypotonically-treated boar spermatozoa with either succinate or pyruvate and malate as substrate was examined. It was found that the pathways involved in the metabolism of succinate was more gossypol-sensitive. The gossypol sensitivity of various electron transport chain (ETC) segments in boar spermatozoa was also investigated with proper choice of electron donors and acceptors. The succinate to cytochrome c segment was the most sensitive one. However this inhibition threshold (1.8 X 10(-5) M gossypol), being higher than either the uncoupling threshold or the concentration threshold at which spermatozoal motility is reduced, suggests that the main target of gossypol antimotility effect does not seem to be the succinate to cytochrome c segment in the ETC.