INS and hyperthyroidism: On the other hand, there are several possible mechanisms involved in thyroid hormones affecting glucose metabolism as follows: (a) reduced half-life of insulin caused by an increasing rate of degradation and enhancing the release of biologically inactive insulin precursors in hyperthyroidism (36, 37), (b) increased intestinal glucose absorption mediated by excess thyroid hormones (38, 39), and (c) thyroid hormones raise GLUT-2 (the glucose transporter in the liver), leading to increased glucose output and abnormal glucose metabolism (40).