title: Stage-specific cellular regulation of inhibin alpha-subunit mRNA expression in the rat seminiferous epithelium.
abstract: To find out the local regulation of inhibin production and its possible paracrine role in the seminiferous epithelium, inhibin alpha mRNA levels were measured in sequential 1 mm segments of rat seminiferous tubules accurately staged by transillumination technique. Highest levels were found at stages XIV-I-IV of the cycle, and lowest at stages VI-VIIb of the cycle. When dividing spermatogonia were selectively destroyed by 3 Gy of high-energy X-irradiation, stage-specific inhibin alpha mRNA levels remained unchanged until 26 and 38 days after irradiation when stages VII and VIII of the cycle showed 6- and 4-fold increases during a selective reduction of pachytene spermatocyte and round spermatid numbers, respectively. The results suggest that these cells at a strictly stage-specific fashion have a paracrine inhibitory effect on Sertoli cell inhibin alpha gene expression. Inhibin alpha mRNA level also correlates closely to the follicle-stimulating hormone-stimulated cAMP production during the cycle of the seminiferous epithelium, but does not seem to have a correlation to spermatogonial DNA synthesis.
authors.affiliation: Department of Anatomy, University of Turku, Finland.
authors.forename: A
authors.initials: A
authors.lastname: Kaipia
authors.forename: M
authors.initials: M
authors.lastname: Parvinen
authors.forename: S
authors.initials: S
authors.lastname: Shimasaki
authors.forename: N
authors.initials: N
authors.lastname: Ling
authors.forename: J
authors.initials: J
authors.lastname: Toppari
mesh_terms: D000818:Animals; D015152:Blotting, Northern; D005640:Follicle Stimulating Hormone / Q000378:metabolism; D005786:Gene Expression Regulation; D015151:Immunoblotting; D007265:Inhibins / Q000235:genetics*; D008297:Male; D009929:Organ Size; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012670:Seminiferous Epithelium / Q000166:cytology / Q000378:metabolism*; D013091:Spermatogenesis; D013737:Testis / Q000378:metabolism / Q000528:radiation effects
chemical_list: D012333:RNA, Messenger; D007265:Inhibins; D005640:Follicle Stimulating Hormone