Urinary catecholamine metabolites in borderline and established hypertension. Relationship to body composition

The urinary excretion of catecholamine metabolites was studied by means of gas chromatography-mass spectrometry in 38 hypertensive patients on a moderately sodium-restricted diet during hospitalization. Twenty-four patients had established hypertension (EHT) and 14 borderline hypertension (BHT) with mean basal morning blood pressures of 155 +/- 14/101 +/- 8 and 132 +/- 9/87 +/- 4 mmHg, respectively. In these two groups of hypertensive patients the mean daily excretion of 4-hydroxy-3-methoxymandelic acid (VMA) was 13.3 +/- 5.9 vs. 14.0 +/- 6.3 nmol/ml and of 4-hydroxy-3-methoxy-phenylglycol (HMPG) 7.8 +/- 4.1 vs. 7.0 +/- 3.9 nmol/ml. These concentrations were not significantly different from the corresponding values of 18 normotensive control persons (mean ambulatory blood pressure 121 +/- 10/74 +/- 9 mmHg, VMA 12.3 +/- 5.5 nmol/ml, HMPG 9.6 +/- 3.9 nmol/ml). The normotensive individuals excreted 23.7 +/- 8.9 nmol/ml of homovanillic acid (HVA), while the two groups of hypertensive patients showed significantly lower HVA excretion, EHT 17.6 +/- 6.2 nmol/ml and BHT 16.1 +/- 5.9 nmol/ml (p less than 0.05). Our findings support the view that no generalized increase in sympathetic activity exists in EHT or BHT. In BHT, but not in EHT, there were correlations between catecholamine metabolite excretion and body weight. The biological significance of the lower HVA concentrations in hypertensive patients compared to control individuals is not clear.