The distribution of betaglycan protein and mRNA in rat brain, pituitary, and gonads: implications for a role for betaglycan in inhibin-mediated reproductive functions.
Betaglycan was reported by our laboratory to serve as an inhibin binding protein and to facilitate the antagonism of activin signaling. Although an accessory receptor for TGFbeta and inhibin, its distribution within reproductive tissues remains largely unexplored. Histochemical analyses reveal betaglycan protein and mRNA distributed throughout the rat reproductive axis. In the brain, betaglycan mRNA is localized in discrete regions of the forebrain and brain stem, including olfactory, septal, and hypothalamic nuclei. In the pituitary, moderate levels of betaglycan protein and mRNA were observed in the anterior and intermediate lobes. Betaglycan immunoreactivity was colocalized with all the pituitary cell subtypes, to the greatest extent with the gonadotrope population. In the gonads, betaglycan mRNA was localized in cellular compartments, coinciding with its protein for the most part. Moderate levels of mRNA were observed in ovarian granulosa cells, with lower expression in the thecal layer and the oocyte. In the testes, betaglycan mRNA was observed in the Leydig and tubule-specific germ cells. This is the first comprehensive report detailing the distribution of betaglycan in mammalian reproductive tissues. The present findings illustrate and support the hypothesis of a modulatory role for betaglycan in TGFbeta and/or inhibin effects in these tissues.
MacConell
Leigh A
LA
Clayton Foundation Laboratories for Peptide Biology, The Salk Institute for Biological Studies, La Jolla, California 92037, USA.
Leal
Angela M O
AM
Vale
Wylie W
WW
D000818:Animals; D001923:Brain Chemistry / Q000502:physiology*; D005260:Female; D017403:In Situ Hybridization; D008297:Male; D023282:Nuclease Protection Assays; D010053:Ovary / Q000378:metabolism*; D010902:Pituitary Gland / Q000378:metabolism*; D011509:Proteoglycans / Q000378:metabolism*; D015347:RNA Probes; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018125:Receptors, Transforming Growth Factor beta / Q000378:metabolism*; D013737:Testis / Q000378:metabolism*
D011509:Proteoglycans; D015347:RNA Probes; D012333:RNA, Messenger; D018125:Receptors, Transforming Growth Factor beta; C071736:betaglycan