title: The expression and localization of inhibin isotypes in mouse testis during postnatal development.
abstract: Inhibin, which is important for normal gonadal function, acts on the pituitary gonadotropins to suppress folliclestimulating hormone (FSH) secretion. The level and cellular localization of the inhibin isotypes, alpha, betaA and betaB, in the testis of mice were examined during postnatal development in order to determine if inhibin expression is related to testicular maturation. Mouse testes were sampled on postnatal days (PNDs) 1, 3, 6, 18, 48 and 120, and analyzed by Western blotting and immunofluorescence. Western blot analysis showed very low levels of inhibin alpha, betaA and betaB expression in the testes at days 1 to 6 after birth. The levels then increased gradually from PND 18 to 48-120, and there were significant peaks at PND 48. Inhibin alpha, betaA and betaB were detected in testicular cells during postnatal development using immunohistochemistry. The immunoreactivity of inhibin alpha was rarely observed in testicular cells during PND 1 to 6, or in the cytoplasmic process of Sertoli cells surrounding the germ cells and interstitial cells during PND 18 to 120. Inhibin betaA and betaB immunoreactivity was rarely observed in the testis from PND 1 to 6. On the other hand, it was observed in some spermatogonial cells, as well as in the interstitial space between PND 48 and PND 120. We conclude that the expression of inhibin isotypes increases progressively in the testis of mice with increasing postnatal age, suggesting that inhibin is associated with a negative feedback signal for FSH in testicular maturation.
authors.affiliation: Department of Veterinary Anatomy, College of Veterinary Medicine and Veterinary Medical Research Center, Chonnam National University, Gwangju 500-757, Korea.
authors.forename: Yujin
authors.initials: Y
authors.lastname: Kim
authors.forename: Joong Sun
authors.initials: JS
authors.lastname: Kim
authors.forename: Myoung Sub
authors.initials: MS
authors.lastname: Song
authors.forename: Heung Sik
authors.initials: HS
authors.lastname: Seo
authors.forename: Jong Choon
authors.initials: JC
authors.lastname: Kim
authors.forename: Chun Sik
authors.initials: CS
authors.lastname: Bae
authors.forename: Seungjoon
authors.initials: S
authors.lastname: Kim
authors.forename: Taekyun
authors.initials: T
authors.lastname: Shin
authors.forename: Sung Ho
authors.initials: SH
authors.lastname: Kim
authors.forename: Changjong
authors.initials: C
authors.lastname: Moon
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D005786:Gene Expression Regulation / Q000502:physiology*; D028322:Inhibin-beta Subunits / Q000235:genetics / Q000378:metabolism*; D007265:Inhibins / Q000235:genetics / Q000378:metabolism*; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D020033:Protein Isoforms / Q000378:metabolism; D021381:Protein Transport / Q000502:physiology*; D013737:Testis / Q000378:metabolism*
chemical_list: D020033:Protein Isoforms; C094377:inhibin-alpha subunit; D007265:Inhibins; D028322:Inhibin-beta Subunits