The response of serum apolipoprotein H to an oral fat load

Abstract

Background: We tested the hypothesis that serum apolipoprotein H (apo H) concentration increases after an oral fat load. Such a study would give valuable insight into whether apo H was influenced by the postprandial state. Methods: Ten male subjects aged 24-48 years were fed 62.5 g of total fat (saturates 12 g, monounsaturates 35.3 g, polyunsaturates 12.5 g). Venous blood was sampled hourly for 5 h post-oral fat load. Results: No significant change in serum apo H concentration occurred following the oral fat load. However, serum apo H in the baseline samples correlated significantly with subject body mass index (r=0.683, P<0.05), body fat mass (r=0.778, P<0.01), lean body mass (r=0.693, P<0.05), serum triglyceride (r=0.732, P<0.02), serum insulin (r=0.808, P<0.01) and insulin resistance index (r=0.794, P<0.01). In stepwise multiple linear regression model, with serum apo A1, apo B, lipoprotein(a), total cholesterol, triglyceride, HDL-cholesterol, LDL-cholesterol, plasma glucose and insulin and apo H as the dependent variable, insulin remained in the model (r=0.81, P<0.01). Conversely, with body mass index, body fat mass, lean body mass and waist/hip ratio in the model and apo H as dependent variable, only body fat mass remained in the model (r=0.78, P<0.01). Conclusions: Serum apo H may be involved in insulin resistance and relates to various indices of adipose tissue, including body fat mass. However, serum apo H concentrations do not significantly change postprandially.