Abstract
Despite suggestions on the role of insulin in triglyceride metabolism, the relationship betweeni nsulin secretory function and familial form of endogenous hypertriglyceridemia has remained unclear. To elucidate this relationship, 83 family members of familial endogenous hypertriglyceridemia including 9 index cases as well as 90 controls matched with age, sex and relative body weight were investigated. All probands revealed primary, endogenous hypertriglyceridemia, hyperinsulinemia, biopsy-proven hepatic steatosis (triglyceride accumulation) and normal activityof post heparin lipoprotein lipase (protamin-inactivated form). A significantly increased insulin secretion expressed as sum of plasma insulin values during oral glucose tolerance test was noted frequently in all age-groups of relatives, usually accompanied by glucose intolerance and hypertriglyceridemia. The first degree relatives of the index cases showed the increased insulin secretion more frequently (52%) than the second degree relatives (21%). Seven pedigrees obviously showed vertical transmission of the combined disorders of hyperinsulinemia and hypertriglyceridemia. H owever, the possibility of monogenic dominant inheritance proved unsupportable, since frequency distribution curves for adjusted blood glucose and plasma insulin and triglyceride in the relatives were similarly shifted to higher values with no apparent bimodality. Obesity was frequent but was not confined to the relatives. Impaired liver function was often noted even in the minors and liver biopsy performed in 2 of them revealed steatosis. Therefore, the insulin resistance expressed as hyperinsulinemia and hyperglycemia seems to be the essential genetic disorder. However, the insulinogenic indices 30 minutes after oral glucose load were significantly higher in the young relatives as compared to the aged; thus, the increased response of pancreatic beta cells to glucose might be more essential in this form of familial hypertriglyceridemia.
