POSTPRANDIAL REDUCTION IN HIGH-DENSITY-LIPOPROTEIN CHOLESTEROL CONCENTRATIONS IN POSTMENOPAUSAL WOMEN - IMPROVEMENT BY 17-BETA-ESTRADIOL

The aim of the study was to characterize postprandial high-density lip oprotein (HDL) cholesterol metabolism in postmenopausal women and to e valuate the effect of replacement therapy with 17 beta-estradiol. Sixt een healthy normolipidemic (plasma cholesterol, 5.39 +/- 0.68 mmol/L; plasma triglycerides [TGs], 1.24 +/- 0.55 mmol/L) postmenopausal women received an oral vitamin A fat tolerance test (50 g fat with 60,000 I U vitamin A/m(2) body surface area). Venous blood samples were taken b efore the test, at hourly intervals up to 8 hours, and 24 hours after ingestion of the fat load for determination of HDL cholesterol, HDL TG , and HDL apolipoprotein (apo) A-I concentrations. TG and vitamin A co ncentrations were also measured. A subgroup of six women were treated with 2 mg micronized 17 beta-estradiol orally each day for 6 weeks, af ter which the oral vitamin A fat tolerance test was repeated. A reduct ion in plasma HDL cholesterol concentrations was observed 3 to 8 hours after ingestion of the fat load, and the minimal postprandial HDL cho lesterol concentration was, on average, 31.7% (P = .04) lower than the fasting HDL cholesterol concentration. HDL cholesterol had returned t o the initial value 24 hours after the fat load. The decrease in postp randial HDL cholesterol concentrations was attenuated by treatment wit h 17 beta-estradiol. The area under the curve (AUC) for the postprandi al reduction in HDL cholesterol improved substantially by 66% during 1 7 beta-estradiol (-2.4 +/- 2.6 mmol . h . L(-1) before 17 beta-estradi ol and -1.1 +/- 1.2 mmol . h . L(-1) during 17 beta-estradiol, P = .03 8). In conclusion, HDL cholesterol concentrations decreased by 32% in the postprandial state in normolipidemic postmenopausal women, indicat ing that HDL cholesterol must be measured in the fasting state. Replac ement therapy with 17 beta-estradiol reduced the postprandial decrease in HDL cholesterol by 66%. This effect of 17 beta-estradiol can be be neficial in reducing the risk of coronary artery disease. Copyright (C ) 1996 by W.B. Saunders Company