INSR and Hyperglycemia: In addition, the homodeficiency of the IGF-1 receptors with heterodeficiency of the insulin receptors results in mild hyperglycemia and decreased β cell mass, while the homodeficiency of the insulin receptors with heterodeficiency of the IGF-1 receptors results in a phenotype similar to that of βDKO mice, suggesting that the autocrine/paracrine insulin is important for the regulation of pancreatic β cell volume.