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.
NPH insulin action, which is the primary reason NPH remains on the market today, because manufacturers sell a variety of premixed insulin formulations. Eventually all animal insulins made by Novo Nordisk were replaced by synthetic, recombinant 'human' insulin. Synthetic 'human' insulin is also complexed with protamine to form NPH. It has an intermediate duration of action, meaning longer than that of regular and rapid-acting insulin, and shorter than long acting insulins (ultralente, glargine or detemir). NPH insulin may be combined with faster acting insulin to allow more accurate dosing and better blood sugar level control. When administered this way, the two insulin