Discrimination of LH, FSH, TSH and ACTH in dissociated porcine anterior pituitary cells by light and electron microscope immunocytochemistry

Using the PAP unlabelled antibody method, LH, FSH, TSH and ACTH were localized at light microscope level in cultured cells dissociated from the porcine adenohypophysis. Antisera were shown to be specific for the β-subunits of the porcine glycoprotein hormones by radioimmunoassay and absorption studies. Using these antisera, it was found that LH and FSH were contained within the same cell, with TSH in a separate cell. When absorbed with LH, anti-porcine ACTH stained a separate distinct population of ACTH cells. Adjacent ultra-thin sections stained with anti-pLHβ Hβ and anti-pFSHβ, and examined at electron microscope level, showed that the ovoid, 150-400 nm secretory granules of the LH/FSH gonadotrophs contained both LH and FSH.