Plasma Free and Conjugated MHPG in Psychiatric Patients

Abstract

• Measures of plasma 3-methoxy-4-hydroxyphenethyleneglycol (MHPG) may be useful for investigating noradrenergic function in certain behavioral and physiologic states. Serial plasma and urine samples were obtained from a diagnostically heterogeneous group of ten psychiatric inpatients over a three- to five-day period. The plasma samples were assayed for free and total MHPG and the urine samples for total MHPG. The variance between patients in both plasma free and conjugated MHPG was markedly greater than the variance within patients. The testretest reliability for free plasma MHPG in both AM VS PM values within and across study days was also significant for both free and conjugated MHPG even though the AM plasma free MHPG values were significantly greater than the PM values. No significant correlations were found between plasma free and conjugated MHPG or between urinary total MHPG and plasma free MHPG.