Aim: The over-expression of CB1 in adult obesity is associated with insulin resistance (IR),but it is not elucidated in childhood obesity. We studied CB1 and endocannabinoid enzymes (EE), Adiponectin (Ad), and Insulin (SI) in lean and obese pre-pubertal (PP) children.
Methods: CB1 mRNA and protein (Pr) expression were studied by RT-PCR, western immunoblotting and immunohistochemistry in primary cultures of adipose tissue. The EE(NAPE-PLD, DAGL-alpha, FAAH, MAGL) expression was assessed by Real-Time PCR. Ad and SI were measured by ELISA and IR by HOMA-IR index.
Results: In the older obese vs older lean children: (1) CB1 Pr was decreased, (2) FAAHmRNA and DAGL-alpha mRNA were increased. Ad was decreased and SI and HOMA-IR increased in the older PP children.
Conclusions: Increased CB1 and decreased adiponectin in older lean PP children may facilitate fat deposition and "physiologic" IR necessary for the increased body growth of puberty. The reduced expression of CB1 in the older obese may be an attempt to reduce lipogenesis to avoid greater insulin resistance.