Insulin the simplest unicellular eukaryotes. Apart from animals, insulin-like proteins are also known to exist in the Fungi and Protista kingdoms. Insulin is produced by beta cells of the pancreatic islets in most vertebrates and by the Brockmann body in some teleost fish. Cone snails "Conus geographus" and "Conus tulipa", venomous sea snails that hunt small fish, use modified forms of insulin in their venom cocktails. The insulin toxin, closer in structure to fishes' than to snails' native insulin, slows down the prey fishes by lowering their blood glucose levels. The preproinsulin precursor of insulin is encoded by the "INS" gene.
Insulin analog required throughout the day representing about 50% of daily insulin requirement, the insulin amount needed at mealtime makes up for the remaining 50%. Non hexameric insulins (monomeric insulins) were developed to be faster acting and to replace the injection of normal unmodified insulin before a meal. There are phylogenetic examples for such monomeric insulins in animals. All insulin analogs must be tested for carcinogenicity, as insulin engages in cross-talk with IGF pathways, which can cause abnormal cell growth and tumorigenesis. Modifications to insulin always carry the risk of unintentionally enhancing IGF signalling in addition to the desired pharmacological properties. There