FADS1 and type 2 diabetes mellitus: Several studies have shown that the activities of delta-6 and delta-5-desaturases are depressed in type II diabetes.(65,66) In a study by Mohan and Das,(65) the intraperitoneal administration of 50 mg of l-arginine led to a significant improvement in the levels of various polysaturated fatty acids (PUFAs) in the liver, plasma and muscle of rats through enhanced activity of delta-6 and delta-5-desaturases.