Comparative study in vivo and in vitro of the differentiation of immunoreactive gonadotropic cells in fetal rat anterior pituitary.
In order to study the mechanisms of the differentiation of gonadotropic cells in fetal rat, an immunocytochemical study was performed in vivo and in vitro with antiporcine beta-LH serum. In vivo, the size of the immunoreactive cells increased greatly between 18 and 19 days of gestation and after a slight increase was observed until 21 days. In vitro, no immunoreactive cells were detected in primordia explanted from 11 to 15 days and cultured until 21 days, in a medium Parker's 199 without any addition. In contrast immunoreactive cells were detected in primordia explanted from 14 days and cultured until 21 days in a medium Parker's 199 containing 20% dialyzed fetal calf serum as well as in the presence of normal fetal calf serum. When the medium Parker's 199 was enriched with insulin (0.5-10 micrograms/ml) and transferrin (5 micrograms/ml) immunoreactive cells were first detected in primordia explanted from 13 days independently of the dose of insulin. However, the size of the immunoreactive cells remained lower than in vivo even at a period equivalent to term. These results suggest that insulin was probably one of the factors stimulating the differentiation of this cell type but other specific factors are needed before 13 days. The comparison of the development of the size of the cells in vivo and in vitro also indicates that other factor(s) acting probably from 18 days of gestation in addition with insulin are required to assure the complete development of these cells.
D000818:Animals; D000936:Antigen-Antibody Complex; D002454:Cell Differentiation; D005260:Female; D005333:Fetus; D007106:Immune Sera; D007986:Luteinizing Hormone / Q000276:immunology / Q000378:metabolism*; D008297:Male; D009924:Organ Culture Techniques; D010903:Pituitary Gland, Anterior / Q000196:embryology* / Q000378:metabolism; D011247:Pregnancy; D051381:Rats; D011919:Rats, Inbred Strains
D000936:Antigen-Antibody Complex; D007106:Immune Sera; D007986:Luteinizing Hormone