Cholecalciferol ameliorates insulin signalling and insulin regulation of enzymes involved in glucose metabolism in the rat heart

Abstract

Context

The evidence on potential cross-talk of vitamin D and insulin in the regulation of cardiac metabolism is very scanty.

Objective

Cholecalciferol was administered to male Wistar rats for six weeks to study its effects on cardiac glucose metabolism regulation.

Materials and methods

An expression, phosphorylation and/or subcellular localisation of insulin signalling molecules, glucose transport and metabolism key proteins were studied.

Results

Circulating non-esterified fatty acids (NEFA) level was lower after cholecalciferol administration. Cholecalciferol decreased cardiac insulin receptor substrate 1 Ser³⁰⁷ phosphorylation, while insulin-stimulated Akt Thr³⁰⁸ phosphorylation was increased. Cardiac 6-phosphofructo-2-kinase protein, hexokinase 2 mRNA level and insulin-stimulated glycogen synthase kinase 3β Ser⁹ phosphorylation were also increased. Finally, FOXO1 transcription factor cytosolic level was reduced.

Conclusion

Vitamin D-related improvement of insulin signalling and insulin regulation of glucose metabolism in the rat heart is accompanied by the decrease of blood NEFA level and dysregulation of cardiac FOXO1 signalling.

Keywords:

• Vitamin D
• heart
• insulin signalling
• glucose metabolism

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

All materials and data are available from the corresponding author upon a reasonable request.

Additional information

Funding

This study was supported by the Ministry of Education, Science and Technological Development of the Republic of Serbia.