Combined βFSH and βLH response to TRH in patients with clinically non-functioning pituitary adenomas
DESIGN, PATIENTS AND MEASUREMENTSForty patients with NFT underwent a standard TRH test (400 μg intravenously). Blood samples for the determination of βFSH, βLH, FSH and LH were collected prior to TRH as well as 15, 30, 45, 60 and 90 minutes following injection. Additionally, cultured adenomatous cells from eight of these patients were exposed to TRH in the absence and presence of octreotide and gonadotropin subunits were determined.
RESULTSTRH elicited a marked rise in circulating βFSH in 29 of 40 individuals and in βLH in 28 of 36 patients with NFT. In a subgroup of eight individuals whose tumours were harvested during surgery and cultured for 7–21 days, TRH increased βFSH or βLH and α-subunit release in cultured adenomatous cells in all cases, including tumours from subjects not responding to TRH in vivo. In this subgroup of patients octreotide inhibited basal βFSH secretion but not basal βLH secretion both in vivo and in primary cultures of NFT cells. Both the in vivoin vitroβFSH, βLH and α-subunit responses to TRH were entirely inhibited by octreotide. In all, 38 of the 40 subjects could be identified by either elevated basal βFSH or βLH levels and/or an abnormal rise in either βFSH or βLH in response to TRH.
CONCLUSIONThe measurement of basal and TRH-stimulated β-FSH and β-LH levels identifies an abnormal hormonal secretory pattern in the vast majority (>90%) of patients with clinically nonfunctioning pituitary tumours.
Document Type: Research Article
Affiliations: 1: Institute of Endocrinology and 2: Department of Hormone Research, The Weizman Institute of Science, Rehovot, Israel 3: Department of Neurosurgery, Tel-Aviv Sourasky Medical Center and Sackler Faculty of Medicine, Tel-Aviv University and the
Publication date: May 1, 1997