INS and Impaired glucose tolerance: Animal and in vitro studies showed that Vacor damaged pancreatic β cells, which led to impaired glucose tolerance in rats (Lee et al. 1988) and to decreased insulin release in isolated rat pancreatic islet cells and hamster insulinoma HIT-T15 cells (Esposti et al. 1996; Taniguchi et al. 1989; Wilson and Gaines 1983).