The Insulin Family: Evolution of Structure and Function in Vertebrates and Invertebrates

¹ Biological Laboratory, Vrije Universiteit, de Boelelaan 1087, NL-1081 HV Amsterdam, The Netherlands

Insulin and related peptides are key hormonal integrators of growth and metabolism in vertebrates. Recently, the amino acid and DNA sequences of insulin-related peptides in invertebrates have become available. The discovery of such peptides in insects and molluscs substantiates the evidence for an early origin and widespread evolution of the insulin superfamily.

In the silkworm Bombyx (Insecta) the prothoracicotropic hormones (bombyxins I, II, and III; previously called PTTH) are produced in the brain and may stimulate synthesis and release of ecdysone; thus they play a central role in insect development. In the freshwater snail Lymnaea (Mollusca), a growth stimulating hormone (molluscan insulin-related peptide; MIP) is produced in the brain, and two other insulin-related peptides are produced in the digestive system. The MIPs are involved in body and shell growth and energy metabolism. The finding that bombyxin and MIP are involved in the control of growth fits with ideas being developed in the vertebrate field that the role of insulin is not confined to glucose metabolism, but is also related to growth.

This article has been cited by other articles:

				J. McRory and N. M. Sherwood Two Protochordate Genes Encode Pituitary Adenylate Cyclase-Activating Polypeptide and Related Family Members Endocrinology, June 1, 1997; 138(6): 2380 - 2390. [Abstract] [Full Text] [PDF]