Effect of choline on central dopaminergic function in normal subjects.

Oral administration of choline (10 g) had no effect on basal serum growth hormone or prolactin concentrations in normal subjects (N = 5). Choline significantly enhanced the increase in growth hormone secretion induced by apomorphine HCl (0.5 mg s.c.). These data suggest that cholinergic mechanisms may enhance hypothalamic-pituitary dopaminergic function in man in contrast to their inhibitory effect on dopaminergic function in the basal ganglia.