Macronutrient composition of the diet differentially affects leptin and adiponutrin mRNA expression in response to meal feeding

A number of adipose-specific genes, including adiponutrin and the adipocytokines, appear to be involved in regulating overall energy balance, as their expression is dysregulated in various obese states and is responsive to feeding. This study determined the effect of meal-feeding diets of markedly different macronutrient composition (70% by weight protein or fat) on the expression of adiponutrin and several adipocytokines in white adipose tissue of rats. Adiponutrin mRNA rapidly increased by at least 8-fold within 3 hours after the high-protein meal. This response was similar to that seen after a high-sucrose meal (70% by weight of sucrose). In contrast, leptin mRNA was unchanged after the high-protein meal, whereas it increased more than 5-fold after a high-sucrose meal. On the high-protein diet the leptin mRNA did not decline upon fasting after the meal, whereas on the high-sucrose diet fasting brought about a rapid decline in leptin mRNA, suggesting that the composition of the diet had altered mRNA turnover. In rats on diets high in either saturated or polyunsaturated fats, adiponutrin mRNA remained at fasting levels even after the meals. Leptin mRNA was unchanged and was maintained at post-meal levels. Resistin and acrp30/adiponectin mRNAs remained unchanged regardless of the macronutrient composition of the diet. The mechanism by which macronutrient composition of the diet is able to differentially influence the expression of adiponutrin and the adipocytokines, leptin, resistin, and acrp30/adiponectin remains to be determined.