IMPAIRED SOMATOMEDIN (SM) GENERATION TEST IN POORLY CONTROLLED INSULIN DEPEDENT DIABETES MELLIITUS (IDDM)

Abstract

Recent studies have suggested a partial block in SM production or growth hormone (GH) action in IDDM. Twelve diabetic children (9 males and 3 females with a mean age of 11.2 ± 3.3 years), six in good control (HbA1C 7.9 - 11.2%) and six in poor control (HbA1C 12 - 15.6%) were studied as follows: the GH response following 100 ug of oral clonidine and the SM generation capacity after i.m. administration of 0.2 u/kg/dose of hGH for 4 days. Poorly controlled diabetics had a significantly higher mean ± SD GH increase after clonidine than did well controlled patients (17.4 ± 4.9 vs 5.7 ± 6.0 ng/ml; p<0.004); the basal GH of both groups were similar (1.6 ± 0.7 vs 2.3 ± 1.4 ng/ml). In contrast the SM response to hGH was significantly decreased in poorly controlled children as compared to well controlled (Δ of 0.3 ± 0.3 vs 1.2 ± 0.4 U/ml, p<0.002). The basal SM levels of both groups were normal for age. Δ GH and Δ SM correlated with HbA1C levels (r = + 0.80, p<0.01;r = -0.79, p < 0.01, respectively);there was no correlation with plasma and urine glucose or serum cholesterol, cortisol and transferin. Our data indicate a blunted SM response to hGH in poorly controlled diabetes; this defect in SM generation is apparently not present in well controlled IDDM. A biologically inactive GH molecule seems unlikely, but circulating inhibitory factors or a still unclear metabolic desangement may be contributing to this defect.