[Secretion of insulin and peptide C in workers exposed to whole body vibration and noise]

Insulin and C-peptide concentrations were studied in serum (by means of radioimmunoassay) after an oral glucose tolerance test in 62 workers occupationally exposed to whole body vibration and noise, and in 30 non-exposed workers of the control group. In the exposed group more frequent occurrence of higher glucose and insulin concentrations, with normal C-peptide concentrations, were found. The observed non-effective hyperinsulinaemia is likely caused by an impaired insulin degradation in the liver and/or an increased production of proinsulin which is assayed simultaneously by IR-I method.