Serum Levels of Insulin-Like Growth Factor (IGF) and IGF Binding Protein in Insulin-Dependent Diabetics during an Episode of Severe Metabolic Decompensation and the Recovery Phase*

Abstract

Serum insulin-like growth factor (IGF) and IGF-binding protein (IGF BP) levels were determined in 13 insulin-dependent diabetic patients (30-60 yr of age) during an episode of severe metabolic decompensation and the recovery phase. After separation by acidic gel filtration, the samples were assayed for IGF using a protein-binding assay (which measures mainly IGF I-related peptides) and for IGF BP by measuring the binding activity, in both assays using IGF I as tracer. The reference standard was a pool of normal adult serum with an assigned potency of 1 U IGF and 1 U IGF BP per ml. The mean IGF level in the uncontrolled state, 0.55 +/- 0.05 (SEM) U/ml, was about half that of normal subjects (1.03 +/- 0.03 U/ml, P less than 0.001). With treatment, IGF levels reached the normal range within 3 days. The pattern of changes in IGF BP levels was roughly similar, although the values in the uncontrolled state were less depressed (0.78 +/- 0.04 U/ml vs. 0.98 +/- 0.04 in normal subjects, P less than 0.01). Highly significant correlations (P less than 0.001) were found between IGF levels and the biological parameters reflecting control of the diabetes: glycosuria (r = -0.60), glycemia (r = -0.52), ketonemia (r = -0.65), and HCO3- (r = 0.58). Similar but less significant correlations were found for IGF BP. The mean GH level during the period of metabolic decompensation (9.0 +/- 1.5 ng/ml) was elevated compared to that after recovery (2.9 +/- 0.8 ng/ml) (P less than 0.025). There was a negative correlation between GH values and IGF levels (r = -0.67, P less than 0.001). The correlation with IGF BP was much less significant (r = -0.38, P less than 0.05). The results clearly reflect the role of insulin and nutritional factors in the control of IGF levels. They also support the notion that the biosynthesis of IGF and IGF BP is not regulated in the same way.

Radioimmunoassay of growth hormone-dependent insulinlike growth factor binding protein in human plasma.

“…The reduction in BP seen in adult diabetics with poor control is consistent with our observations of decreased IGF-I levels (28), although, as recently reviewed (28), a variety of other studies show no change in IGF-I, or even an increase. Ligand-binding measurements of BP in diabetic subjects also show reduced levels, which were consistent with our RIA measurements (10,31). However, in contrast to the study ofRieu and Binoux (31), we saw no correlation between the degree ofdiabetic control and BP levels in individual patients.…”

Circulating IGF-I concentrations are low and not correlated to glycaemic control in adults with type 1 diabetes

“…In two other studies reporting low IGF-I concentrations in large samples of patients, no information was given regarding circulating IGF-I concentrations in relation to HbA 1c (12,15). In contrast, in diabetic ketoacidosis there are reports of very low IGF-I concentrations, which were increased by insulin treatment, indicating that IGF-I concentrations are affected by severe metabolic decompensation (31,32). Taken together, these data indicate that subcutaneous insulin substitution only partly restores the circulating concentrations of IGF-I in patients with type 1 diabetes of long duration.…”

Serum DHEA-S Level Is Associated with the Presence of Atherosclerosis in Postmenopausal Women with Type 2 Diabetes Mellitus

“…Lowered serum IGF-I level was suggested to predict worsening of insulinmediated glucose uptake in older people [23]. In patients with type 2 diabetes, serum IGF-I levels were dependent on the degree of glucose control, with near normal IGF-I levels in well-controlled diabetes, whereas they tended to decrease in poorly controlled diabetes [24,25]. Thus, circulating DHEA and IGF-I levels seem to be affected by diabetic status and might be associated with atherosclerosis in diabetic patients differently than in non-diabetic subjects.…”