Sensitivity to the Anorectic Effects of Leptin Is Retained in Rats Maintained on a Ketogenic Diet despite Increased Adiposity

Background: Rats maintained on a ketogenic diet (KD; 80% fat, 15% protein, 5% carbohydrate) have increased adiposity and leptin as compared to chow-fed controls (CH; 16% fat, 19% protein, 65% carbohydrate), although body weights and daily caloric intakes do not differ. Methods: Rats maintained on a KD or CH were assessed for responsivity to intraperitoneal (i.p.) or intracerebroventricular (i.c.v.) leptin. Hypothalamic gene expression was evaluated to determine the effects of KD on proopiomelanocortin (POMC) mRNA expression and components of the leptin-signaling system. Results: Caloric intake by KD rats was decreased at a lower dose of i.p. leptin (100 µg) than was required to reduce intake by CH rats (leptin, caloric intake was reduced in KD rats as compared to intake following i.p. saline; p Conclusion: These data demonstrate that despite increased adiposity, leptin and markers of leptin resistance, responsivity to the anorectic effects of exogenous leptin is retainable during maintenance on a KD.