Expression and activities of 11betaHSD enzymes in the testes and reproductive tracts of sexually immature male pigs.

In light of studies implicating glucocorticoids in the control of testicular steroidogenesis and/or spermatogenesis, the objective of this study was to characterise the expression and activities of the 11beta-hydroxysteroid dehydrogenase (11betaHSD) enzymes in the testis and reproductive tract of the pre-pubertal pig. Although 11betaHSD1 and 11betaHSD2 mRNA transcripts and proteins were co-expressed in all regions of the reproductive tract, cortisol-cortisone inter-conversion was detectable in the testis, caput epididymidis and bulbourethral glands only. In homogenates of these 3 tissues, the apparent K(m) for NADP(+)- and NAD(+)-dependent 11beta-dehydrogenase activities ranged between 152-883 and 47-479 nmoll(-1), respectively. Irrespective of the pyridine nucleotide co-substrate, estimates of V(max) were consistently two orders of magnitude higher in the testis. Moreover, while, in each tissue, levels of cortisol oxidation were comparable in the presence of either NADP(+) or NAD(+), maximal rates of NAD(P)(+)-dependent cortisol oxidation were up to 33-fold greater than the V(max) for NADPH-dependent reduction of cortisone. We conclude that in the testis, caput epididymidis and bulbourethral gland of the immature pig, NADP(+)- and NAD(+)-dependent 11betaHSD enzymes catalyse net inactivation of cortisol, suggesting a physiological role for these enzymes in limiting local actions of glucocorticoids within these male reproductive tissues prior to puberty.