The effect of bromocriptine on growth hormone (GH) responses to TRH was studied in 14 insulin-dependent diabetics. The effect of this dopaminomimetic agent was inconstant. In the 6 patients with inadequate responses of GH to TRH, bromocriptine inhibited this response. Inversely, it appeared capable of stimulating a GH response in certain non-responders. The could suggest the existence of disturbances of dopaminergic control of GH secretion in diabetics, but the lack of reproducibility of responses of GH to TRH makes this an uncertain conclusion.