Insulin production in the mouse uterus

Traditional paradigms hold that insulin production is restricted to the β cells of the pancreas. However, this long held view of insulin genesis has been challenged by recent studies showing that insulin can be produced by alternative, non-pancreatic cells. In this context, insulin has been reported to be produced in the brain, liver, bone marrow and in some reproductive organs. The functional consequences of extrapancreatic insulin production remain uncertain but could have a wide range of implications varying from diabetes to regulation of fertility. Insulin is most well-known for its role in controlling glucose homeostasis, which it does through activation of signaling cascades encompassing the phosphoinositide 3-kinase (PI3K) pathway. However, insulin is also a growth factor that is capable of encouraging cell proliferation through the extracellular signal-regulated kinase (ERK) - mitogen-activated protein kinases (MAPK) pathway. In this review we consider the growing body of literature supporting instances of extrapancreatic insulin production, and seek to establish whether such sources play a conserved or divergent role to that of the more widely studied insulin produced in the pancreas.