Details

Autor(en) / Beteiligte

• Reed, Grant
• Cefaratti, Christie
• Berti-Mattera, Liliana N.
• Romani, Andrea

Titel

Lack of insulin impairs Mg2+ homeostasis and transport in cardiac cells of streptozotocin-injected diabetic rats

Ist Teil von

• Journal of cellular biochemistry, 2008-06, Vol.104 (3), p.1034-1053

Ort / Verlag

Hoboken: Wiley Subscription Services, Inc., A Wiley Company

Erscheinungsjahr

2008

Quelle

MEDLINE

Beschreibungen/Notizen

• Serum and tissue Mg2+ content are markedly decreased in diabetic patients and animals. At the tissue level, Mg2+ loss progresses over time and affects predominantly heart, liver and skeletal muscles. In the present study, alterations in Mg2+ homeostasis and transport in diabetic cardiac ventricular myocytes were evaluated. Cardiac tissue and isolated cardiac ventricular myocytes from diabetic animals displayed a decrease in total Mg2+ content that affected all cellular compartments. This decrease was associated with a marked reduction in cellular protein and ATP content. Diabetic ventricular myocytes were unable to mobilize Mg2+ following β‐adrenergic receptor stimulation or addition of cell permeant cyclic‐AMP. Sarcolemma vesicles purified from diabetic animals, however, transported Mg2+ normally as compared to vesicles from non‐diabetic animals. Treatment of diabetic animals with exogenous insulin for 2 weeks restored ATP and protein levels as well as Mg2+ homeostasis and transport to levels comparable to those observed in non‐diabetic animals. These results suggest that in diabetic cardiac cells Mg2+ homeostasis and extrusion via β‐adrenergic/cAMP signaling are markedly affected by the concomitant decrease in protein and ATP content. As Mg2+ regulates numerous cellular enzymes and functions, including protein synthesis, these results provide a new rationale to interpret some aspects of the cardiac dysfunctions observed under diabetic conditions. J. Cell. Biochem. 104: 1034–1053, 2008. © 2008 Wiley‐Liss, Inc.