The significance of alpha-subunit as a tumor marker for gonadotropin-producing pituitary adenomas.
We studied gonadotropin hormone alpha-subunit and gonadotropin secretion in four patients with gonadotropin-producing pituitary adenomas. All four patients had elevated plasma alpha-subunit levels, ranging from 2.8-8.5 ng/ml (normal, less than 0.5 ng/ml). alpha-Subunit responses to LHRH were less than those in seven patients with primary gonadal failure. The relative proportions of the gonadotropin and alpha-subunit peaks in one patient were the same before and after LHRH administration, based on gel filtration studies of plasma. The alpha-subunit levels decreased little during testosterone treatment in the two adenoma patients so treated. Immunohistochemical study of the adenomas from two patients demonstrated definite staining with alpha-subunit and gonadotropin antisera. Elevated plasma levels of alpha-subunit and its relative unresponsiveness to LHRH stimulation or testosterone suppression suggest that the alpha-subunit originated in tumor tissue and that its measurement is useful for the diagnosis of a gonadotropin-producing tumor in patients with elevated plasma levels of LH and/or FSH.
D000236:Adenoma / Q000097:blood*; D000328:Adult; D000368:Aged; D002850:Chromatography, Gel; D005640:Follicle Stimulating Hormone / Q000097:blood; D015292:Glycoprotein Hormones, alpha Subunit; D007987:Gonadotropin-Releasing Hormone; D006651:Histocytochemistry; D006801:Humans; D007120:Immunochemistry; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D008875:Middle Aged; D010446:Peptide Fragments / Q000097:blood*; D010908:Pituitary Hormones, Anterior / Q000097:blood*; D010911:Pituitary Neoplasms / Q000097:blood*; D013739:Testosterone / Q000494:pharmacology
D015292:Glycoprotein Hormones, alpha Subunit; D010446:Peptide Fragments; D010908:Pituitary Hormones, Anterior; D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone