Failure of inhibition by TRH of L-Dopa stimulated GH secretion in patients with alcoholic cirrhosis of the liver.

We have investigated the effects of a single oral dose of L-Dopa (500 mg) or of an i.v. infusion of TRH (1 mg dissolved in 400 ml of saline solution) or both administered together, on GH release in men with alcoholic cirrhosis of the liver, and compared them with responses in normal subjects. The results obtained in normal subjects confirm that TRH does not modify plasma GH levels, L-Dopa elevates GH concentrations, while the administration of these two drugs together significantly inhibits GH release induced by oral L-Dopa. In contrast, in patients with alcoholic cirrhosis of the liver, the following results were obtained: 1 TRH infusion significantly increased plasma GH levels which were steadily elevated throughout the experiment; 2 oral administration of L-Dopa provoked a significant rise in blood GH over the basal values similar to that observed in normal subjects; 3 when TRH and L-Dopa are administered at the same time a GH increase like that observed after L-Dopa alone was obtained. These results clearly demonstrate that in patients with alcoholic cirrhosis of the liver the normal inhibitory effect of TRH on L-Dopa induced GH release is completely lost.