INS and obesity due to melanocortin 4 receptor deficiency: In this study and in contrast to the others mentioned above [166,195,196], oxytocin levels were inversely correlated with BMI as well as additional obesity-related adverse metabolic parameters (e.g., HbA1c, glucose and fasting insulin levels, total cholesterol, triglycerides, LDL cholesterol, and HOMA-IR) [197].