Comparison of TRF, propranolol-glucagon, insulin and glucose stimulation tests in acromegaly

In 7 acromegalic patients growth hormone responses were studied following administration of synthetic TRF, propranolol-glucagon, insulin, and glucose p.o. Except for the glucose tolerance test, a good reproducibility of the STH response was observed. In 5 out of the 7 patients, there was a distinct rise in the plasma STH level after TRF. All patients with a positive insulin tolerance test responded to TRF, as did the two late responders to glucagon; the early responder to the latter test did not respond to TRF. It has been suggested (Liuzzi et al. 1974a) that TRF might be used as a screening test for detecting hypothalamic dependency of the acromegaly. This study suggests that further study is required before accepting this hypothesis and that a response to a combination of tests (TRF, glucagon, insulin) might be a better screening method.