Previous studies of our group demonstrated that women with PCOS, when compared to normal women, had a (i) greater than 5-fold increase in the renal clearance of DCI, (ii) 50% reduction in the circulating concentration of DCI, and (iii) decreased insulin-stimulated release of DCI-IPG during an oral glucose tolerance test (OGTT). Moreover, insulin sensitivity (as determined by frequently sampled intravenous glucose tolerance test [FSIVGTT]) correlated inversely with renal clearance of DCI. In addition, it appears that obesity needs to be present for the abnormality in renal clearance of DCI to be present in PCOS, and obesity does not seem to have an effect in DCI renal clearance in normal women.