Triglyceride removal efficiency and lipoprotein lipases: effects of Oxandrolone

Very low density lipoprotein triglyceride turnover rate, fractional turnover rate, and half-life were studied using Glycerol ^?3H to label VLD-TG in 16 patients with familial Type IV hyperlipoproteinemia. The patients were maintained on an isocaloric diet with determination of triglyceride turnover after 2 wk of placebo, and a second determination after 2 wk of Oxandrolone (an anabolic-androgenic synthetic steroid). On placebo, mean very low density lipoprotein triglyceride (VLD-TG) was 539, falling on Oxandrolone to $\text{254 mg}\text{100 ml}$ (p < 0.05). Mean half-life ($\text{T}\text{1}\text{2}$) was 10.3 hr on placebo and was shortened to 5.2 hr on drug (p < 0.05). The fractional turnover rate (FTR) on placebo was 0.104 ± 0.016 hour^?1, and rose to 0.166 ± 0.016 on drug (p < 0.05). Mean turnover rate (TR) rose slightly from 17.6 mg/kg/hr on placebo to 19.04 mg/kg/hr on Oxandrolone. Both postheparin lipolytic activity (PHLA) and postheparin triglyceride lipase (TGL) were appreciably increased on drug, rising respectively from 0.297 μeq FFA/ml/min and 11.7 mμeq FFA/ml/hr (on placebo) to 0.396 and 23.7 (on drug). The changes (Δ) in VLD-TG on Oxandrolone correlated with $\text{Δ T}\text{1}\text{2}$ (R = 0.761) and with Δ FTR (R = ?0.532). Oxandrolone may lower very low density lipoprotein triglyc eride by substantially increasing fractional turnover rate and shortening half-life while slightly augmenting turnover rate and improving efficiency of VLD-TG removal.