THE MICROCALORIMETRIC APPROACH TO HUMAN SPERM PHYSIOLOGY

Heat conduction microcalorimetry has been adopted to evaluate overall basal metabolism in human spermatozoa. Heat output has also been measured in the presence of some metabolic inhibitors in an attempt to relate it to different cellular energetic pathways. Owing to the presence in spermatozoa of mechanochemical events of motility, microcalorimetric data have also been compared with those derived from cell motility analysis. When basally evoked heat was recorded in a rotating batch calorimeter, a mean value of 127.7 mcal h-1 per 10(8) spermatozoa was obtained, which was greatly different from that measured in a static calorimeter. On this basis, the adoption of microcalorimetric instruments in (human) sperm heat production studies is critically analysed. Dose-response experiments show that metabolic poisons, azide, fluoride and rotenone, induced both heat output and motility reduction. Our first data indicate that, given appropriate experimental conditions, batch calorimetry could represent a promising, powerful tool in the still largely obscure, challenging field of human male gamete physio(patho)logy.