Effect of Human Myotubes-Derived Media on Glucose-Stimulated Insulin Secretion

Abstract EN

Fasting to postprandial transition requires a tight adjustment of insulin secretion to its demand, so tissue (e.g., skeletal muscle) glucose supply is assured while hypo-/hyperglycemia are prevented.

High muscle glucose disposal after meals is pivotal for adapting to increased glycemia and might drive insulin secretion through muscle-released factors (e.g., myokines).

We hypothesized that insulin influences myokine secretion and then increases glucose-stimulated insulin secretion (GSIS).

In conditioned media from human myotubes incubated with/without insulin (100 nmol/L) for 24 h, myokines were qualitatively and quantitatively characterized using an antibody-based array and ELISA-based technology, respectively.

C57BL6/J mice islets and Wistar rat beta cells were incubated for 24 h with control and conditioned media from noninsulin- and insulin-treated myotubes prior to GSIS determination.

Conditioned media from insulin-treated versus nontreated myotubes had higher RANTES but lower IL6, IL8, and MCP1 concentration.

Qualitative analyses revealed that conditioned media from noninsulin- and insulin-treated myotubes expressed 32 and 23 out of 80 myokines, respectively.

Islets incubated with conditioned media from noninsulin-treated myotubes had higher GSIS versus control islets (p<0.05).

Meanwhile, conditioned media from insulin-treated myotubes did not influence GSIS.

In beta cells, GSIS was similar across conditions.

In conclusion, factors being present in noninsulin-stimulated muscle cell-derived media appear to influence GSIS in mice islets.