Adipocyte insulin binding and action in moderately obese NIDDM patients after dietary control of plasma glucose: reversal of postbinding abnormalities.

Studies of fat cells from patients with newly diagnosed, untreated non-insulin-dependent diabetes mellitus (NIDDM) have revealed severe abnormalities in insulin action on glucose transport and metabolism. To determine whether these defects can be reversed if good glycemic control is reached by dietary treatment, eight moderately obese NIDDM subjects were studied at diagnosis and again when the patients had been in good glycemic control induced by low-energy dieting for at least 2 mo (absence of glycosuria and fasting plasma glucose less than 7 mM). Average body weight decreased by 8 kg (P less than .05). Fasting plasma glucose decreased from 11.5 +/- 1.2 to 6.9 +/- 0.9 mM, whereas fasting serum insulin concentrations were unchanged. Adipocyte insulin binding at tracer concentration (15 pM, 37 degrees C) was not changed significantly (1.94 +/- 0.52 to 2.05 +/- 0.62% per 30 cm2 surface area/ml). The basal (non-insulin-stimulated) glucose transport (tracer glucose concentration 5 microM) increased from 25 +/- 12 to 44 +/- 14 pmol X 90 min-1 X 10 cm-2 surface area (P less than .02). The maximally insulin-stimulated glucose transport rate increased from 35 +/- 20 to 78 +/- 26 pmol/90 min (P less than .01). The percentage insulin response above basal levels increased from 31 +/- 40 to 89 +/- 58% (P less than .01). The insulin sensitivity (half-maximally stimulating insulin concentrations) was also improved (P less than .05). Glucose conversion rates to total lipids increased 34 +/- 62 and 65 +/- 80% in basal cells and maximally insulin-stimulated cells, respectively (.2 greater than P greater than .1, .1 greater than P greater than .05).(ABSTRACT TRUNCATED AT 250 WORDS)