Serotonin uptake stimulating peptide found in plasma of normal individualsand in some autistic urines

We have isolated a tripeptide from normal plasma and autistic urines which stimulates the uptake of serotonin (5-HT) into platelets. This peptide was purified by high-performance liquid chromatography (HPLC) and characterized by sequenation and mass-spectrometry. Synthetic peptide showed cochromatog raphy with the biological sample in the HPLC systems used. Close to 60% of the autistic children diagnosed using the Diagnostic Statistical Manual III -R had an increased HPLC peak eluting like this peptide in their urines com pared with controls.