INS and diabetes mellitus: The main criteria for the development of diabetes and the effectiveness of the investigated therapeutic and prophylactic measures currently used in the studies are glucose content, insulin and glycosylated hemoglobin of blood plasma; the number of β-cells in the islets of the pancreas; the area of distribution of the sugar curve; the index of insulin resistance; and the results of histology and histochemistry of the pancreas and other organs [51,52,53,54].