SEXUAL DIFFERENCES IN EFFECTS OF ILEAL INTERPOSITION SURGERY ON MELANOCORTIN-4 RECEPTOR DEFICIENT RATS

Abstract

Objectives: We aimed to determine the metabolic differences between male and female rats after ileal interposition surgery, and determine whether the remission of insulin resistance after ileal interposition is dependent on melanocortin-4 receptor signaling in both male and female rats.

Methods: All age-matched male and female rats were treated with either sham or ileal interposition surgery. Glucose tolerance tests and body composition analysis were then performed. 

Results: Loss of Mc4r function in both male and female rat induced obesity; male KO Sham, not female KO Sham, showed impaired glucose tolerance; insulin resistance of both KO Sham and PF Sham is significantly higher than that of KO IT and PF IT respectively in both male and female rats; IT surgery decreased both fat percentage and fat mass in female rats, not in male rats, in the long run.

Conclusions: Melanocortin-4 Receptor signaling is not necessary for the underlying beneficial effects of ileal interposition on glucose metabolism and insulin resistance. Female rats might get more stable benefits than male rats after the surgery .