Light and electron microscopic identification of pituitary cells containing growth hormone and prolactin in the pigeon ( Columba livia), using the immunoglobulin-enzyme bridge technique

Localization of cells containing growth hormone or prolactin was studied in the pituitaries of immature and adult pigeons with the peroxidase antibody bridge technique employing rabbit antisera against bovine growth hormone (bSTH) and ovine prolactin (oPRL). Light microscopy showed that cells reacting with anti-bSTH serum were restricted to the caudal lobule and stained orange with Brookes' trichrome stain like the A i or α cells. The anti-oPRL positive cells were, on the contrary, found in the cephalic lobule, and stained rose with Brookes' stain, like the A 2 or η cells. Electron microscopy showed that the anti-bSTH positive cells contain oval or rounded secretion granules, while the anti-oPRL positive cells were characterized by polymorphic secretion granules. In both cell types some stain on the secretion granules was observed, but reaction products were, in addition, found in the cytoplasm.