Influence of Gossypol on the Motility and Dynein ATPase Activity of Sea Urchin Sperm

Abstract

That gossypol affects spermatogenesis and sperm maturation in the epididymis [1, 2, 3], testicular steroidogenesis [4] and metabolism of male accessory organs [5], resulting in a reduction of sperm count, have all been demonstrated, as has its capacity to inhibitin vitro the motility of spermatozoa of various species, including that of human beings [6, 7], other mammals [8], and even sea urchins [9, 10]. Gossypol interacts with various macromolecules such as acrosin [11]. The motility arrest may result from a reduction in energy supply through inhibition of lactate dehydrogenase-X [12], pyruvate dehydrogenase [13], and the succinate to cytochrome c segment of the electron transport chain [14]. Oxidative phosphorylation and mitochondrial Mg²⁺-ATPase are also suppressed by gossypol [15, 16]. However, the influence of this compound on the motile machinery of sperm flagella, i.e., the tubulin-dynein system that converts the chemical energy of ATP to mechanical energy to be used for flagellar movement [17], has not been reported although it has been claimed that the flagellar ATPase activity of boar spermatozoa is probably not inhibited by gossypol [18].