Failure of serotonin inhibitor to effect nocturnal GH and prolactin secretion in patients with Duchenne muscular dystrophy.

Growth hormone (GH) and prolactin (PRL) secretion was evaluated in seven patients with Duchenne muscular dystrophy. GH and PRL levels following sleep and 24 h mean serum GH and PRL concentrations were normal in these subjects. Overnight GH and PRL concentrations were evaluated in four of these patients before and following administration of the serotonin inhibitor, parachlorophenylalanine (PCPA). Although PCPA produced a significant decrease in urinary 5HIAA concentrations, the treatment had no significant effect on GH and PRL levels. These findings raise the possibility that serotonin may not be involved in nocturnal GH and PRL secretion in these patients.