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pubmed:abstractText |
KK mice are genetically diabetic animals, showing glucose intolerance and insulin resistance. We examined the effects of 3,3',5-triiodo-L-thyronine (T3) on the blood glucose level and on mRNA levels of muscle cell differentiation markers in hyperglycemic KK mice. T3 treatment (T1, 1 mg; T3, 3 mg; T10, 10 mg/kg/day) of KK mice for 4 days caused a decrease in blood glucose level by 11%, 25%, and 24%, respectively, without affecting body weight. Skeletal muscle of mice treated with T3 (T10) showed a 98% increase in the mRNA level of the glucose transporter isotype 4 (Glut4). In contrast, T3 treatment did not affect the mRNA level of the isotype 1 (Glut1) transporter. The mRNA level of a muscle cell specific differentiation marker, MyoD, showed a significant increase in the T3 treatment group with an accompanying enhancement of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA level. These results suggest that T3 stimulates muscle cell differentiation in vivo, concomitant with a stimulation of cellular glucose metabolism, thus decreasing the blood glucose level in hyperglycemic KK mice.
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pubmed:affiliation |
Molecular Medicine Laboratories, Institute for Drug Discovery Research, Yamanouchi Pharmaceutical Co., Ltd., Tsukuba, Ibaraki, Japan. simokawa@yamanouchi.co.jp
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