Leptin Receptor mRNA in Bull Ejaculated Spermatozoa

Leptin is a potential satiety factor and plays an important role in both metabolism and reproduction; both leptin and its receptor (Ob-R) have been detected in human spermatozoa, thus suggesting leptin involvement in male gamete physiology. This experiment was designed to investigate leptin receptor [the long isoform (Ob-Rb)] mRNA in bull ejaculated spermatozoa by RT-PCR and southern hybridization. Total RNA was isolated from ejaculated spermatozoa and purified by different methods. Although the concentrations of RNA determined by all methods (except SDS/Proteinase K, lowest amount of RNA recovery) were similar, ethidium bromide staining was only detectable in lanes containing the samples isolated by sodium dodecyl sulphate (SDS) and SDS/citric acid extraction which produced higher RNA concentration. Ob-Rb mRNA was detected in all samples using southern hybridization after RT-PCR; it was shown only in three of them by RT-PCR. We may conclude that Ob-Rb mRNA is present in bull spermatozoa and leptin perhaps exerts physiological effects, as already demonstrated in humans and pigs.