FKBP1B and glucose measurement: Although the blood glucose and plasma insulin concentrations for FKBP12.6−/− mice were normal in both random and fasted states, insulin secretion in response to glucose tolerance stress in these FKBP12.6-deficient mice was severely depressed relative to their FKBP12.6+/+ littermates (Noguchi et al., 2008 ▶).