PPARA and diabetes mellitus: A rat model of diabetes that received marine collagen (2.25, 4.5, and 9 g/kg/d for 4 weeks) indicated improved glucose metabolism and insulin resistance, as well as up-regulated glucose transporter type 4 (GLUT 4) in skeletal muscles, and peroxisome proliferator activated receptor-α (PPAR-α) in the liver.