GNMT and obesity due to melanocortin 4 receptor deficiency: Additionally, we found that the accumulation of S-adenosylmethionine (SAM), a Met metabolite associated with a decrease in glycine-N-methyltransferase (Gnmt) expression/activation in renal tubular cells, possibly contributes to the activation of mTORC1 and impairment in autophagy and leads to the pathogenesis of DKD in rats with T2DM and obesity.