Similar effects of prolactin and dbcAMP upon human spermatozoa metabolism

Studies were carried out of the effects of prolactin (0.5-1.0 mU) and 3'5' dibutyryl cyclic AMP -(dbcAMP) (100-500 ng) on oxygen uptake and (U-14C) glucose and (1-14C) acetate utilization by human spermatozoa. Both molecules induce a significant increase (P < 0.01) in oxygen uptake when acetate, glucose, pyruvate and lactate were used as substrates, although differences were noted in the induction effect depending on the substrate used (Tukey's multiple comparisons after ANOVA) (P < 0.01). The production of 14CO2 from glucose and labelled acetate was also statistically increased (P < 0.01) by prolactin (from 15.15 to 25.32 nmoles CO2/hour/10(8) sperm cells) as well as by dbcAMP (15.15 to 34.95 nmoles CO2/hour/10(8) sperm cells). From these results we conclude that the activator effects of prolactin and dbcAMP on human spermatozoa with respect to the studied parameters are similar and that prolactin may be an activator of spermatic adenylyl cyclase.