Insulin (medication) testing and occasionally skin biopsy. First line therapy against insulin hypersensitivity reactions include symptomatic therapy with antihistamines. The affected persons are then switched to a preparation that does not contain the specific agent they are reacting to or undergo desensitization. Insulin is an endogenous hormone, which is produced by the pancreas. The insulin protein has been highly conserved across evolutionary time, and is present in both mammals and invertebrates. The insulin/insulin-like growth factor signalling pathway (IIS) has been extensively studied in species including nematode worms (e.g."C. elegans"), flies ("Drosophila melanogaster") and mice ("Mus musculus"). Its mechanisms of action are highly
Insulin receptor The main activity of activation of the insulin receptor is inducing glucose uptake. For this reason "insulin insensitivity", or a decrease in insulin receptor signaling, leads to diabetes mellitus type 2 – the cells are unable to take up glucose, and the result is hyperglycemia (an increase in circulating glucose), and all the sequelae that result from diabetes. Patients with insulin resistance may display acanthosis nigricans. A few patients with homozygous mutations in the "INSR" gene have been described, which causes Donohue syndrome or Leprechaunism. This autosomal recessive disorder results in a totally non-functional insulin receptor. These patients have low-set,