RPS6KB1 and obesity due to melanocortin 4 receptor deficiency: Plasma TG-hydrolysis activity (Fig. 8d) and LPL activity (Fig. 8e) were increased, by almost 15% as compared with LacZ mice, to an extent similar to those in obese DN-S6K mice (Fig. 7i), resulting in the improvement of obesity-related hypertriglyceridemia (Fig. 8f).