CNR1 and obesity due to melanocortin 4 receptor deficiency: Conditional expression of cannabinoid receptor 1 (Cb1r) in the liver of the transgenic line Tg(-2.8fabp10a: Tetoff-Cb1r-2 A-EGFP)two23 promotes hepatic lipid accumulation and steatosis, which is important for food intake, weight gain, and various pathological features linked to obesity [142].