AIMTo investigate the in vitro effects of insulin and leptin on human sperm motility, viability, acrosome reaction and nitric oxide (NO) production.

METHODSWashed human spermatozoa from normozoospermic donors were treated with insulin (10 microIU) and leptin (10 nmol). Insulin and leptin effects were blocked by inhibition of their intracellular effector, phosphotidylinositol 3-kinase (PI3K), by wortmannin (10 micromol) 30 min prior to insulin and leptin being given. Computer-assisted semen analysis was used to assess motility after 1, 2 and 3 h of incubation. Viability was assessed by fluorescence-activated cell sorting using propidium iodide as a fluorescent probe. Acrosome-reacted cells were observed under a fluorescent microscope using fluorescein-isothiocyanate-Pisum sativum agglutinin as a probe. NO was measured after treating the sperm with 4,5-diaminofluorescein-2/diacetate (DAF-2/DA) and analyzed by fluorescence-activated cell sorting.

RESULTSInsulin and leptin significantly increased total motility, progressive motility and acrosome reaction, as well as NO production.

CONCLUSIONThis study showed the in vitro beneficial effects of insulin and leptin on human sperm function. These hormones could play a role in enhancing the fertilization capacity of human spermatozoa.

Acrosome Reaction ; drug effects ; Cell Survival ; drug effects ; Flow Cytometry ; Humans ; Hypoglycemic Agents ; pharmacology ; In Vitro Techniques ; Insulin ; pharmacology ; Leptin ; pharmacology ; Male ; Nitric Oxide ; metabolism ; Sperm Motility ; drug effects ; Spermatozoa ; drug effects ; metabolism