Intolerance to
glucose in certain kinds of
lipomatosis is well documented. This article describes a euglucaemic hyperinsulinaemic clamp study of alterations in
glucose and/or
insulin metabolism in four members of a single family with
familial multiple lipomatosis. Fifteen normal subjects were studied as controls. The four patients exhibited no alteration in tolerance to orally administered
glucose. When a Biostator
Glucose-Controlled
Insulin Infusion System (GCIIS) was used to clamp glycaemia at 4.44 mmol/L with successive
insulin infusion rates of (a) 0.5 (b) 1.0 or (c) 5.0 mU/kg/min, there was no difference between patients and controls as regards the value of M, the rate of
glucose infusion, but the concentrations of immunoreactive
insulin recorded during the last 40 minutes of each phase of the clamp were greater in patients than in controls (45 +/- 2 vs 27 +/- 2 uU/mL (p less than 0.01), 83 +/- 2 vs 60 +/- 5 uU/mL (p less than 0.05) and 537 +/- 48 vs 377 +/- 25 uU/mL (p less than 0.05) for
insulin infusion rates (a), (b) and (c) respectively), and the ratio M/IRI was consequently smaller for patients than controls (1.92 +/- 0.41 vs 3.06 +/- 0.19 (p less than 0.05) for an
insulin infusion rate of 5 mU/kg/min). The metabolic clearance rate of
insulin was likewise slower in patients than controls (p less than 0.01). It is concluded that the four patients studied (all members of the same family) have sub-normal sensitivity to
insulin secondary to a sub-normal metabolic clearance rate for
insulin.