RETN and obesity due to melanocortin 4 receptor deficiency: Second, obesity’s complicated endocrine activity, which is characterized by the production of leptin (27), resistin (28), and adiponectin (29), can also cause direct kidney injury, causing oxidative stress (30), abnormal lipid metabolism (31), renin-angiotensin-aldosterone system activation (32), chronic inflammation (33), and insulin resistance (34).