To study the effects of 20 days of bed rest on HDL cholesterol, lipoprotein lipase, hepatic triglyceride lipase, cholesterol ester transfer protein and lecithin-cholesterol acyltransferase.Design.
A 20-day intervention study.Setting.
Makita general hospital.Subjects.
Five male and five female healthy participants, mean age 20.4 years, range 19-24 years.Interventions.
Twenty days of bed rest.Main outcome measures.
Lipid, lipoprotein, lipoprotein lipase, hepatic triglyceride lipase, cholesterol ester transfer protein and lecithin-cholesterol acyltransferase.Results.
Fasting HDL, HDL2 and HDL3 cholesterol levels decreased from 1.748 to 1.404 mmol L−1 (P < 0.01), from 0.807 to 0.628 mmol L−1 (P < 0.01) and from 0.939 to 0.784 mmol L−1 (P < 0.05), respectively, while VLDL triglyceride levels increased from 0.365 to 0.754 mmol L−1 (P < 0.05). Plasma post-heparin lipoprotein lipase activity decreased from 0.494 to 0.418 μmol mL−1 h−1 (P < 0.01), but plasma post-heparin hepatic triglyceride lipase activity and cholesterol ester transfer protein activity did not change during bed rest. Lecithin-cholesterol acyltransferase activity increased from 72.5 to 84.8 nmol mL−1 h−1 (P < 0.001).Conclusions.
Twenty days of bed rest induced a decline in HDL cholesterol levels and an increase in VLDL triglyceride levels. When considering lipoprotein lipase, hepatic triglyceride lipase, cholesterol ester transfer protein and lecithin-cholesterol acyltransferase as factors in the decreased HDL cholesterol, the contribution of lipoprotein lipase is suggested.