Immunoreactive sites and accumulation of somatomedin-C in rat Sertoli-spermatogenic cell co-cultures.
Sertoli-spermatogenic cell co-cultures prepared from sexually immature rats (20-22 days old) and maintained in serum-free, hormone/growth factor-supplemented medium were used to determine the cell-specific localization of the growth factor somatomedin-C (SM-C). SM-C localization studies were carried out by indirect immunofluorescence using a monoclonal antibody (sm-1.2) to SM-C. In cultured rat hepatocytes, Sertoli and testicular peritubular cells, SM-C immunoreactivity was observed as a diffuse distribution of discrete immunofluorescent granules. Radio-immunoassay experiments using a rabbit antibody against human SM-C showed that testicular peritubular cells and Sertoli cells in primary culture accumulated SM-C in the medium. In spermatogenic cells co-cultured with subjacent Sertoli cells, immunoreactive SM-C was associated with pachytene spermatocytes but not with spermatogonia or early meiotic prophase spermatocytes (leptotene or zygotene). Both Sertoli cells and pachytene spermatocytes displayed binding sites for exogenously added SM-C. SM-C6 binding to spermatocytes reaching an advanced stage of meiotic prophase suggests a possible role of this growth factor in the meiotic process.
D000818:Animals; D000911:Antibodies, Monoclonal; D003994:Bucladesine / Q000494:pharmacology; D002450:Cell Communication; D002478:Cells, Cultured; D003470:Culture Media; D003513:Cycloheximide / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D005640:Follicle Stimulating Hormone / Q000494:pharmacology; D013006:Growth Hormone / Q000494:pharmacology; D007334:Insulin-Like Growth Factor I / Q000032:analysis / Q000276:immunology / Q000378:metabolism*; D008297:Male; D008854:Microscopy, Electron; D051381:Rats; D012708:Sertoli Cells / Q000032:analysis / Q000378:metabolism* / Q000648:ultrastructure; D013002:Somatomedins / Q000378:metabolism*; D013090:Spermatocytes / Q000032:analysis / Q000378:metabolism* / Q000648:ultrastructure; D013091:Spermatogenesis; D013093:Spermatogonia / Q000032:analysis / Q000378:metabolism / Q000648:ultrastructure; D013737:Testis / Q000166:cytology
D000911:Antibodies, Monoclonal; D003470:Culture Media; D013002:Somatomedins; D003994:Bucladesine; D007334:Insulin-Like Growth Factor I; D005640:Follicle Stimulating Hormone; D013006:Growth Hormone; D003513:Cycloheximide