Quantification of in Vivo ³ H-Estrogen Uptake by Individual Anterior Pituitary Cell Types of Male Rat:

A refined version of the combined dry-mount autoradiographic-immunocytochemical technique (Keefer DA, Stumpf WE, Petrusz P: Cell Tissue Res 166:25, 1976) is described in detail. In vivo nuclear estrogen uptake is measured by silver grain counting in immunocytochemically stained gonadotropes (G), somatotropes (S), lactotropes (L), corticotropes (C), and thyrotropes (T) of male rats. In rats 1 day after orchidectomy, the order of nuclear estrogen uptake was S = L greater than G = C greater than T, with T concentrating less than half as much radioactivity as L or S. Fifteen percent of anterior pituitary cells neither concentrated estrogen nor stained immunocytochemically. Estrogen uptake was examined in gonadotropes 1, 14, and 50 days after orchidectomy and was found to be identical at all three times. Estrogen uptake in gonadotropes of rats 14 days following orchidectomy and treatment with progesterone was reduced significantly. Guidelines for reliable quantification of the autoradiographic data is discussed.