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 resistance the likelihood of Type 2 diabetes mellitus. Also, insulin resistance often is associated with a hypercoagulable state (impaired fibrinolysis) and increased inflammatory cytokine levels. Another factor that may promote insulin resistance is Leptin, a hormone produced from the ob gene and adipocytes. Its physiological role is to regulate hunger by alerting the body when it is full. From an adaptation perspective, it is possible that leptin resistance was favorable for survival during periods when food was scarce. Today however studies show that lack of leptin causes severe obesity and is strongly linked with insulin resistance. Leptin replacement in mice with