Glucose intolerance in teleost fish: face or fiction?

Teleost fish are generally considered to be glucose intolerant. This mini-r eview examines some of the background and the possible mechanistic bases fo r this statement. Glucose intolerance is a clinical mammalian term meaning that a glucose load results in persistent hyperglycemia. Teleost fish show persistent hyperglycemia that is generally coincident with transient hyperi nsulinemia. The fact that teleost generally have high plasma insulin compar ed with mammals implies insulin-deficiency is not a suitable explanation fo r this persistent hyperglycemia. Instead, peripheral utilization of glucose is probably the principle cause of hyperglycemia. Recent evidence for musc le insulin receptors, glucose transporters and hexokinase/glucokinase is re viewed and future experimental directions are suggested. If by altering per ipheral glucose utilization fish could become more glucose tolerant, costs to the aquaculture industry may be substantially reduced. (C) 2001 Elsevier Science Inc. All rights reserved.