Rapid radioimmunoassay of plasma GH and its application to the judgement of surgical results in patients with acromegaly.

Abstract

To improve the surgical results in patients with acromegaly, rapid radioimmunoassay (RIA) of plasma GH was developed and this method was applied for quick judgement of whether transsphenoidal hypophysectomy was performed successfully or not. The best reaction temperature and the shortest incubation time were proved to be 40 degrees C and 16 min, respectively. The GH values obtained by this method and the usual RIA method were correlated well (r = 0.9, p less than 0.001). Using the rapid RIA it became possible within 35 min just after the termination of the hypophysectomy to report the data to the neurosurgeons. This RIA method was applied for 5 patients with acromegaly undergoing transsphenoidal hypophysectomy. In two cases plasma GH decreased markedly (62.0-71.4% decreases from preoperative value) at the termination of the hypophysectomy, and later fell to normal ranges. The other three cases showed only slight decreases (7.7-17.3%), and the operation was judged as unsuccessful. Therefore, two of these cases were followed by further removal of residual tumors which resulted in steep declines of GH. In the remaining one the further operation was not performed, because surgical removal of the adenoma was believed by the surgeons to be complete. In conclusion, rapid RIA of plasma GH is possible within 16 min and this method is of significant value to improve the surgical results of acromegalic patients.