Regulated production of activin A and inhibin B throughout the cycle of the seminiferous epithelium in the rat

• Published in: Journal of endocrinology Vol. 190; no. 2; pp. 331 - 340
• Main Authors: Okuma, Y, O’Connor, A E, Hayashi, T, Loveland, K L, de Kretser, D M, Hedger, M P
• Format: Journal Article
• Language: English
• Published: Colchester BioScientifica 01.08.2006; Portland Press
• Subjects: Activins - analysis; Activins - biosynthesis; Animals; Biological and medical sciences; Bucladesine - pharmacology; Cytoplasm - chemistry; Enzyme-Linked Immunosorbent Assay - methods; Fundamental and applied biological sciences. Psychology; Hormone metabolism and regulation; Immunohistochemistry - methods; Inhibins - analysis; Inhibins - biosynthesis; Interleukin 1 Receptor Antagonist Protein; Interleukin-1 - metabolism; Male; Mammalian male genital system; Rats; Rats, Sprague-Dawley; Regular papers; Seminiferous Epithelium - chemistry; Seminiferous Epithelium - metabolism; Sertoli Cells - chemistry; Sialoglycoproteins - pharmacology; Spermatogenesis - physiology; Spermatozoa - chemistry; Stimulation, Chemical; Tissue Culture Techniques; Vertebrates: reproduction; Rat; Spermatogenesis; Cytokine; Rodentia; Inhibin; Male genital duct; Testicle; Male genital system; Biological activity; Vertebrata; Mammalia; Adult animal; Interleukin 1; Seminiferous tubule; Activin; Localization
• ISSN: 0022-0795; 1479-6805
• DOI: 10.1677/joe.1.06706

Production and regulation of activin A and inhibin B during the cycle of the seminiferous epithelium were investigated in adult rats. Immunohistochemistry localised the activin βA-subunit to the Sertoli cell cytoplasm, with much weaker expression in spermatocytes and spermatids. Both activin A and inhibin B, measured by ELISA were secreted by, seminiferous tubule fragments over 72 h in culture. Activin A was secreted in a cyclic manner with peak secretion from tubules isolated at stage VIII. Tubules collected during stage VI produced the least activin A. Inhibin B secretion was highest from stage IX-I tubules and lowest from stage VII tubules. Addition of interleukin-1β (IL-1β) had relatively little effect on activin A or inhibin B secretion in culture. In contrast, the peak secretion of activin A by stage VIII tubules was blocked by co-incubation with an excess of human recombinant IL-1 receptor antagonist, whereas inhibin B secretion increased slightly. Dibutyryl cAMP stimulated activin A secretion by late stage VII and VIII tubules and stimulated inhibin B across all stages. These data indicate that activin A and inhibin B are cyclically regulated within the seminiferous epithelium, with endogenous IL-1 (presumably IL-1α produced by the Sertoli cells), responsible for a peak of activin A production subsequent to sperm release at stage VIII. These data provide direct evidence that production of activin A and inhibin B by the Sertoli cell is locally modulated by IL-1α , in addition to FSH/cAMP, under the influence of the developing spermatogenic cells.