Adiponutrin is a recently identified gene of unknown function that is expressed exclusively in adipose tissues. To provide information about its physiological regulation and possible function, the effect of meal-feeding rats on the expression of adiponutrin mRNA in white adipose tissue was studied. A high-sucrose meal increased adiponutrin mRNA levels by at least 5-fold within 3 h. Post-meal levels returned to pre-meal levels with a half-life of about 5 h. The induction was prevented by injection of actinomycin-D prior to the meal. This pattern of expression was very similar to that seen for leptin mRNA. There were only minimal, or no, effects on acrp30/adiponectin, resistin, adipsin, or stearoyl-CoA desaturase 1. Adiponutrin appears more like leptin with respect to its acute regulation by meal-feeding than to any of the other adipokines or to enzymes directly involved in lipogenesis. This suggests that adiponutrin could be involved in overall energy homeostasis, as is leptin. (C) 2003 Elsevier Science (USA). All rights reserved.