PEPTIDE HISTIDINE METHIONINE AND VASOACTIVE-INTESTINAL-PEPTIDE LEVELSIN HUMAN CEREBROSPINAL-FLUID - AGE-RELATED-CHANGES AND ABSENCE OF A CORRELATION WITH SERUM PROLACTIN

Serum levels of prolactin (PRL), peptide histidine methionine (PHM) an d vasoactive intestinal peptide (VIP) were measured in 97 subjects and cerebrospinal fluid (CSF) levels of PHM and VIP were measured in 50 s ubjects by specific radioimmunoassays to investigate correlations betw een them. The chromatographic studies revealed that PHM and C-terminal extended form of PHM, peptide histidine valine occurred in human seru m and CSF. Significant age-related increases of CSF PHM (P < 0.02) wer e observed in both males and females, whereas an age-related decrease of serum PRL level was found in females (P < 0.01). In contrast, neith er serum VIP, serum PHM nor CSF VIP changed significantly with age. Th ere was a significant positive correlation (P < 0.002) between VIP and PHM in serum, but not in CSF. The close relation between VIP and PHM in serum meets one's expectation because of their derivation from a co mmon precursor. In CSF, these two peptides did not change in parallel with each other. These results may reflect the alteration in metabolis m of PHM in CSF. Finally, there was no correlation between serum PRL c oncentrations and either serum or CSF levels of the peptides, suggesti ng that neither VIP nor PHM levels in CSF as well as in serum can infl uence the basal PRL secretion in subjects without endocrine disorders.