Effects of Physiological Levels of Exogenous Steroids on Metabolism of Testicular, Cauda Epididymal and Ejaculated Bovine Sperm1

Abstract

Testicular, cauda epididymal and/or ejaculated sperm were incubated in vitro with exogenous steroids at essentially physiological concentrations (< 160 nM). A charcoal stripping technique was used to reduce the amount of endogenous steroid bound to sperm. Effects of 6 or 12 individual steroids on energy metabolism of charcoal stripped and nonstripped sperm were evaluated. Metabolic differences among nonstripped testicular, cauda epididymal and ejaculated sperm were confirmed. Charcoal-stripped sperm had metabolic characteristics differing from those of non-stripped sperm, but these differences were not abolished by adding steroid. No consistent alteration of metabolic characteristics, e.g., glucose composition, adenine nucleotide levels, O2 consumption or CO2 production was associated with inclusion of any steroid in the incubation mixture. No single androgen at physiological concentration alters energy metabolism of sperm.