Effect of sex hormones on protamine inactivated and resistant postheparin plasma lipases.

Effects of estrogens and the synthetic anabolic-androgenic steroid, Oxandrolone, on extrahepatic (protamine inactivated) and hepatic (protamine resistant) lipases in postheparin plasma, were assessed in 15 subjects with familial hypertriglyceridemia. In six women receiving conjugated equine estrogen (1.25 mg/day), mean (+/- SE) postheparin protemine inactivated triglyceride lipase (PI-TGL) was depressed to 0.23 +/- 0.10 mumol FFA/ml/hr, and protamine resistant lipase was depressed to 5.3 +/- 0.5 mumol FFA/ml/hr. In the 2-wk period after estrogens were discontinued, PI-TGL remained depressed, 0.54 +/- 0.24, while PR-TGL increased to 7.3 +/- 0.88, p=less than 0.05. Mean triglycerides fell insignificantly from 628 +/- 136 to 447 +/- 44 mg/100 ml when estrogens were discontinued. There was no significant correlation between changes in PR-TGL and triglycerides when estrogens were stopped. In four women with familial hypertriglyceridemia, Oxandrolone significantly increased PR-TGL in two, increased PI-TGL in three, and reduced triglycerides in two. In five men with familial hypertriglyceridemia, Oxandrolone reduced triglycerides in four, increased PR-TGL in four, but had no effect on PI-TGL. For the nine hypertriglyceridemic subjects increments in PR-TGL failed to correlate significantly with decrements in triglyceride, (r=0.309, p is greater than 0.1). Selective alteration of PR-TGL and PI-TGL by estrogens and Oxandrolone may provide an approach to better understanding of the interaction of lipases and triglycerides in familial and acquired hypertriglyceridemia.