Plasma endorphins in Rett syndrome: preliminary data.

Plasma levels of beta-endorphin (beta-EP) and prolactin (PRL) were measured in 5 girls with Rett syndrome and in a control group before and after giving 10 mg metoclopramide i.v. beta-lipotropin (beta-LPH) was only measured in basal conditions. Basal values of beta-EP and beta-LPH were lower than in control individuals. The responses of plasma beta-EP to metoclopramide in Rett syndrome patients were less intense than in control individuals, while the PRL increase in girls with Rett syndrome was significantly higher than in control subjects. These preliminary data suggest a derangement of the dopaminergic system.