Inhibins in the Male Göttingen Miniature Pig: Leydig Cells Are the Predominant Source of Inhibin B

Abstract

ABSTRACT:The expression of inhibin subunits in the testes of the Göttingen miniature pig was examined by in situ hybridization and immunohistochemistry. In addition, the major forms were determined by enzyme-linked immunosorbent assay (ELISA). Strong positive immunostaining for the inhibin ␣ subunit was observed in Sertoli and late-stage germ cells, but it was weak in Leydig cells. However, Leydig cells showed strong positive staining for the ␤A subunit, but Sertoli cells and spermatogonia showed a weak reaction. Strong positive immunostaining for the ␤B subunit was observed in Leydig cells but spermatogonia showed weak staining for it. In contrast to the staining specificity of inhibin ␣ and ␤A subunits, the ␤B subunit did not exhibit positive staining in Sertoli cells. In situ hybridization revealed that although the ␣ subunit mRNA signal was highly expressed in all cell types, the reaction appeared to be stronger in Sertoli cells and spermatogonia than in Leydig cells. ␤A subunit mRNA expression was somewhat identical to that of the ␣ subunit, however, germ cells showed a weak stain for it. A strong, positive mRNA signal for the ␤B subunit was confined to Leydig cells and late-stage germ cells. ELISA results showed that concentrations of inhibin B and inhibin pro-␣C were high in the circulation and testes. In contrast, inhibin A levels in both plasma and testes were undetectable. The present results strongly suggest that inhibin B is the major form of circulating inhibin and that Leydig cells are the predominant source of this dimeric inhibin in male Göttingen miniature pigs. Furthermore, the germ cells also appear to be an important source of circulating inhibins.

Dynamics of insulin-like factor 3 and its receptor expression in boar testes

“…The quality of fractionated cells was verified by determining the expression of HSD3B (HSDB1), PRM1, and INHA, which are expressed specifically by Leydig cells (Raeside & Renaud 1983, Chemes et al 1992, germ cells (Domenjoud et al 1991), and both Sertoli and Leydig cells (Jin et al 2001) respectively. The fractionated testicular cells were frozen and stored in liquid nitrogen.…”

Evidence for expression of relaxin hormone-receptor system in the boar testis

“…The fractionated testicular cells were snap frozen and stored in liquid nitrogen for extraction of RNA. The quality of cellular fractionation was verified by detecting 3-b hydroxysteroid dehydrogenase (HSD3B), protamine 1 (PRM1) and inhibin a (INHA) gene expression, which are specifically expressed by Leydig cells (Raeside & Renaud 1983, Chemes et al 1992, germ cells (Domenjoud et al 1991) and both Sertoli and Leydig cells ( Jin et al 2001) respectively.…”

“…3A). The purity of these fractionated cells was also verified by determining the expression of HSD3B, PRM1 and INHA, which are expressed specifically by Leydig cells (Chemes et al 1992), germ cells (Domenjoud et al 1991) and both Sertoli and Leydig cells ( Jin et al 2001) respectively. Fractionation was shown to be quite satisfactory, i.e.…”

Immunolocalization of Inhibin/Activin Subunit Proteins During the Breeding Season in Testes and Scented Glands of Muskrats (Ondatra zibethicus)

“…In the stallion, golden hamster and dog, the inhibin α, β A and β B subunits are present in both Sertoli and Leydig cells [10,16,24], and in adult monkeys, all three subunits are localized predominantly in Sertoli cells [8,36]. Previous studies showed that inhibin B is the major form of inhibins secreted from testes in men, Japanese macaques and Gottingen miniature pigs [7][8][9], but in the ram, inhibin A, and not inhibin B, was produced in testicular tissues [15]. In the present study, inhibin  and inhibin ( A and  B ) subunits were both expressed in testicular and scented glandular tissues, clearly indicating that apart from testicular tissues, the scented gland was an important source of inhibins in the muskrats.…”