Studies in hypertriglyceridaemia. VI: Serum lathosterol concentration is raised in hypertriglyceridaemic non-diabetic males with hyperinsulinaemia.

Abstract

To assess the cholesterol synthesis rate in primary hypertriglyceridaemia using the serum unesterified lathosterol concentration as an indicator. A cross-sectional, case-control study. The Karolinska Hospital, Stockholm. Randomly selected hyper- (n = 53) and normotriglyceridaemic (n = 57) males, 40-50 years, with a fasting serum triglyceride concentration (mean +/- SD) of 3.81 +/- 1.65 and 1.28 +/- 0.53 mmol L-1, respectively. The exclusion criterion was diabetes mellitus, defined according to the World Health Organization (WHO) guidelines. To compare the fasting serum concentration distributions of lathosterol, a cholesterol precursor, in hyper- and normotriglyceridaemic groups. Thirty-six per cent of the hypertriglycerdaemic group had raised serum lathosterol concentrations, based on the 90th percentile of the lathosterol distribution of the normotriglyceridaemic group. In the hyper- but not in the normotriglyceridaemic group, lathosterol concentration was directly correlated with serum insulin responses to oral (r = 0.38; P = 0.007) and intravenous (r = 0.41; P = 0.005) glucose challenges. One-third of a randomly selected non-diabetic hypertriglyceridaemic population had an increased serum lathosterol concentration and this might indicate an increased cholesterol synthesis rate compatible with increased production of VLDL particles, possibly as the result of chronic hyperinsulinaemia.