|Budget Amount *help
¥1,900,000 (Direct Cost : ¥1,900,000)
Fiscal Year 1993 : ¥400,000 (Direct Cost : ¥400,000)
Fiscal Year 1992 : ¥600,000 (Direct Cost : ¥600,000)
Fiscal Year 1991 : ¥900,000 (Direct Cost : ¥900,000)
In mammals, the direction of sex differentiation of primordial gonad into a testis or an ovary can be controlled by a gene located on the Y-chromosome, but the factors involved in gene-regulatory cascade leading to morphological testicular differentiation is not clear. The mammalian gonad is a complex structure formed by diverse cell lineages, the germ and the somatic cells. Testicular differentiation in rats begins with Sertoli cell differentiation on 13 day of fetal age, followed by seminiferous cord formation and Leydig cell differntiation. This study examined by three different approaches to elucidate the roles of growth factors (TGF-beta, inhibit, EGF, FGF, IGF-II) in rat gonadal differentiation and development during perinatal period, because these growth factors playd a wide range of roles for embryonic development as well as many endocrine, paracrine and autocrine functions.
1. Localization and expression patterns of these growth factors in developing rat gonads throughout the p
erinatal period, from just before the onset of gonadal sex differentiation to postnatal weaning age, were examined immunohistochemically. Each growth factor was expressed in sex-, cell-, and stage-specific manners.
2. Effects of these growth factors on developing rat gonads were examined morphologically in indifferent gonads from 13 day fetal rats which were cultured for 4 days in growth factor or anti-serum containing medium. Inhibin suppressed both the seminiferous cord formation and the germ cell meiosis.
3. The somatic cells in experimentally masculinized fetal rat ovaries, which were transplanted either close to co-grafting fetal tests beneath the renal capsule of the castrated adult or into the adult testicular subcapcular site, showed similar seminiferous cord-like structure formation and immunohistochemical expression of growth factors to those in the co-grafted fetal testes.