Expression of chorionic gonadotrophin in human pituitary adenomas

Department of Medicine, University of Bristol, UK.

In addition to the classical anterior pituitary hormones, many human pituitary adenomas express hormone genes ectopically. Expression of glycoprotein hormone alpha-subunit and, less commonly, free luteinizing hormone beta (LH-beta) or follicle-stimulating hormone beta is characteristic of endocrinologically inactive adenomas, a subgroup thought to be derived predominantly from the gonadotroph line. Thyrotrophin beta expression in these tumours is unusual, and specific chorionic gonadotrophin beta (CG-beta) expression, identified using oligonucleotide probes that reliably distinguish LH-beta and CG-beta in situ, is not well described. Using in situ hybridization histochemistry with a CG-beta transcript-specific oligonucleotide probe and a non-specific LH/CG-beta oligonucleotide and riboprobe, we have demonstrated specific CG-beta expression in two of 35 random pituitary adenomas; LH-beta expression occurred in a further eight adenomas. Unlike prolactin, growth hormone and proopiomelanocortin, which are transcribed in the vast majority of cells in their respective hormone-positive tumour subtypes, the pattern of LH/CG-beta was typically a scattering of single or small clusters of hormone-positive cells in a predominantly LH/CG-beta-negative tumour. Finally, although bona fide CG-beta expression in human pituitary adenomas does occur, it is only at an incidence similar to that described for carcinomas of other tissues.

This article has been cited by other articles:

				P. Chanson, J. Pantel, J. Young, B. Couzinet, J.-M. Bidart, and G. Schaison Free Luteinizing-Hormone Beta-Subunit in Normal Subjects and Patients with Pituitary Adenomas J. Clin. Endocrinol. Metab., May 1, 1997; 82(5): 1397 - 1402. [Abstract] [Full Text] [PDF]