BACKGROUND AND AIMS: Insulin is a major post-prandial muscle-anabolic hormone. A substantial loss of skeletal muscle mass occurs in insulin-deprived diabetes and is reversed by insulin treatment. Myostatin is a negative regulator of muscle mass upregulated in several chronic catabolic conditions. Whether myostatin expression is altered in insulin-deprived diabetes is unknown. In spite of opposite effects on muscle mass the potential role of basal circulating insulin in the regulation of myostatin expression is also undetermined. METHODS: We measured (Northern Blot) myostatin transcript levels in muscle groups with different fiber composition in streptozotocin-diabetic male rats receiving one of the following treatments for eight weeks: (1) control (C); (2) diabetes without treatment (DM); (3) diabetes with once-daily slow-acting insulin treatment (INS). RESULTS: INS normalized plasma insulin and prevented weight reduction observed in DM. In fast-twitch gastrocnemius muscle myostatin transcript levels were unchanged (P>0.4) in both DM and INS compared to C. Myostatin transcripts were not measurable in any group in slow-twitch soleus muscle. CONCLUSIONS: Muscle-specific myostatin expression is not increased under catabolic conditions in insulin-deprived diabetes. Insulin treatment also does not change myostatin transcript levels. The data provide the first assessment of potential interplay between insulin and myostatin and they do not support a major role of circulating insulin in the in vivo regulation of myostatin gene expression. A role of myostatin in muscle catabolism in chronic insulin-deprived diabetes is also not indicated by the current results.

Myostatin expression is not altered by insulin deficiency and replacement in streptozotocin-diabetic rat skeletal muscles.

BARAZZONI, ROCCO;ZANETTI, MICHELA;BOSUTTI, ALESSANDRA;STEBEL, MARCO;CATTIN, LUIGI;BIOLO, GIANNI;GUARNIERI, GIANFRANCO
2004

Abstract

BACKGROUND AND AIMS: Insulin is a major post-prandial muscle-anabolic hormone. A substantial loss of skeletal muscle mass occurs in insulin-deprived diabetes and is reversed by insulin treatment. Myostatin is a negative regulator of muscle mass upregulated in several chronic catabolic conditions. Whether myostatin expression is altered in insulin-deprived diabetes is unknown. In spite of opposite effects on muscle mass the potential role of basal circulating insulin in the regulation of myostatin expression is also undetermined. METHODS: We measured (Northern Blot) myostatin transcript levels in muscle groups with different fiber composition in streptozotocin-diabetic male rats receiving one of the following treatments for eight weeks: (1) control (C); (2) diabetes without treatment (DM); (3) diabetes with once-daily slow-acting insulin treatment (INS). RESULTS: INS normalized plasma insulin and prevented weight reduction observed in DM. In fast-twitch gastrocnemius muscle myostatin transcript levels were unchanged (P>0.4) in both DM and INS compared to C. Myostatin transcripts were not measurable in any group in slow-twitch soleus muscle. CONCLUSIONS: Muscle-specific myostatin expression is not increased under catabolic conditions in insulin-deprived diabetes. Insulin treatment also does not change myostatin transcript levels. The data provide the first assessment of potential interplay between insulin and myostatin and they do not support a major role of circulating insulin in the in vivo regulation of myostatin gene expression. A role of myostatin in muscle catabolism in chronic insulin-deprived diabetes is also not indicated by the current results.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11368/2574224
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