Quantitative immunocytochemical studies on the gonadotrophs isolated from the pituitary of the male rat.

Quantitative studies on the population of the gonadotropic cells in the pituitary of adult male rats were performed after trypsic dissociation of the pituitary glands and immunoenzymatic staining with anti-beta-LH or anti-beta-FSH antisera. Number, area and extinction of labelled cells were measured by use of an image analyser and a cytophotometer. The gonadotrophs represent approximately 14% of the pituitary cells. The mean area of gonadotrophs is significantly larger after staining with anti-beta-LH serum than after staining with anti-beta-FSH serum. Planimetric measurement of the gonadotrophs reveals their variability in size ranging between 30 and 160 microns2. Moreover, the size distribution depends on the staining serum used: more numerous small-sized cells (less than 75 microns2) are stained with anti-beta-FSH serum than with anti-beta-LH serum, which conversely stains more numerous large-sized cells. Cytophotometric measurements indicate that immunostaining varies greatly among cells of the same size class and that the staining intensity appears to increase according to the cell size. These results emphasize the morphofunctional heterogeneity of the gonadotropic cell population.