Insulin decreases blood glucose concentration. It increases cell permeability to monosaccharides, amino acids and fatty acids. It accelerates glycolysis, the pentose phosphate cycle, and glycogen synthesis in liver. Heterodimer of a B chain and an A chain linked by two disulfide bonds. Stored in spherulous cells prior to secretion. Belongs to the insulin family. Was originally (PubMed:2531072) thought to originate from the sponge Geodia cydonium, but, on the basis of phylogenetic studies (Ref.2) it seems very probable that the DNA sequence coding for this protein comes from a rodent as agreed by the original authors (Ref.3). It is also doubtful that this is a real active insulin.