THE USE OF BETA-SUBUNITS OF GONADOTROPIN HORMONES IN THE FOLLOW-UP OFCLINICALLY NONFUNCTIONING PITUITARY-TUMORS

OBJECTIVE Clinically nonfunctioning pituitary adenomas (NFA) are mostl y of gonadotroph origin, However, increased levels of circulating horm ones or subunits in patients with NFA usually do not cause clinical sy mptoms, nor are they used as biological tumour markers, In this study we assessed the value of measuring beta subunits of gonadotrophin horm ones in the post-operative follow-up of patients bearing these tumours , DESIGN Patients harbouring NFA were studied before and three months after transphenoidal pituitary surgery, beta-LH and beta-FSH levels we re measured before and following TRH administration on the two occasio ns, Hormone levels were analyzed in relation to imaging studies perfor med before and after surgery. PATIENTS Twenty four patients operated a t the Tel Aviv-Sourasky Medical Centre for NFA, RESULTS Pathological b eta-FSH and beta-LH levels were detected in 79% and 60% of patients re spectively. beta-LH levels decreased after surgery but there were no s ignificant changes in beta-FSH levels. There was a tendency for tumour s with high basal beta-LH levels to be larger and to have a poor surgi cal outcome. Normalization of beta-LH levels post-operatively was usua lly associated with a decrease in tumour mass or complete removal of t he tumour, Persistent pathological responses of beta-LH to TRH after s urgery were common in patients with residual tumours on imaging. Never theless there were exceptions to this pattern, rendering post-operativ e beta-LH levels insufficiently reliable as a marker for the presence of residual tumour, CONCLUSION Although there appears to be a relation ship between beta-LH levels, tumour size and surgical outcome, this as sociation is presently insufficient to allow the routine use of either basal or TRH induced beta-LH responses in the post-surgical follow-up of clinically nonfunctioning pituitary adenomas.