Interleukin‐6 mediates exercise‐induced increase in insulin sensitivity in mice

Apr 24, 2012Experimental physiology

Interleukin-6 links exercise to improved insulin sensitivity in mice

AI simplified

Circadian Biology on OpenScience ↗PubMed ↗DOI ↗

Abstract

The glucose uptake rate in the muscle was lower in IL-6-deficient mice compared to wild-type mice (398 ± 44 versus 657 ± 41 nmol g(-1) min(-1), P < 0.01).

No difference in serum disappearance of a glucose tracer was observed between IL-6-deficient and wild-type mice after exercise (P = 0.5).
A high-fat diet decreased insulin sensitivity in both IL-6-deficient and wild-type mice, indicated by a 20% increase in glucose area under the concentration-time curve (P < 0.05).
Wild-type mice with access to running wheels maintained their insulin sensitivity and serum retinol-binding protein-4 (RBP-4) levels despite a high-fat diet.
IL-6-deficient mice did not experience the same protective effects from running, showing similar decreases in insulin sensitivity as sedentary IL-6-deficient mice (P = 0.4).
IL-6-deficient mice displayed a 14% increase in serum RBP-4 compared to baseline levels despite access to running wheels (P < 0.01).

AI simplified

Interleukin-6 (IL-6) is released from working skeletal muscle during exercise. We investigated the acute and the long-term beneficial effects of IL-6 on exercise-induced glucose uptake in skeletal muscle and insulin sensitivity. The acute effect on exercise-induced glucose uptake was measured in IL-6-deficient (IL-6(-/-)) mice and wild-type control animals using a tracer technique. There was no difference in serum disappearance of (3)[H]2-deoxyglucose after a single bout of exercise between IL-6(-/-) and wild-type mice (13565 ± 426 versus 14343 ± 1309 d.p.m. min ml(-1), P = 0.5). The glucose uptake rate in the extensor digitorum longus muscle was, however, lower in IL-6(-/-) compared with wild-type mice (398 ± 44 versus 657 ± 41 nmol g(-1) min(-1), P < 0.01). In a long-term study, we monitored insulin sensitivity, serum retinol-binding protein-4 (RBP-4) levels, running activity, food intake, body weight and body composition in IL-6(-/-) and wild-type mice on a high-fat diet (HFD), with or without access to running wheels. In sedentary IL-6(-/-) and wild-type mice, the HFD decreased insulin sensitivity (glucose area under the concentration-time curve increased about 20% during an insulin tolerance test, P < 0.05 for both genotypes versus baseline) and led to a 30% increase in serum RBP-4 levels (P < 0.01 for both genotypes versus baseline). Wild-type mice with access to running wheels were protected against these effects of the HFD and maintained their baseline insulin sensitivity and serum RBP-4 levels. In contrast, IL-6(-/-) mice did not benefit from running to the same extent as wild-type animals. The IL-6(-/-) mice with access to running wheels had a similar decrease in insulin sensitivity to their sedentary littermates (glucose area under the concentration-time curve during an insulin tolerance test in runners versus sedentary IL-6(-/-) HFD mice, 312 ± 14 versus 340 ± 22 mmol min l(-1), P = 0.4) and displayed a 14% increase in serum RBP-4 compared with baseline levels (P < 0.01). Our results indicate that endogenous IL-6 contributes to the exercise-induced increase in insulin sensitivity, but plays only a minor role for glucose uptake into skeletal muscle during exercise.

Full Text

Full text is available at the source.

View full text (PDF) ↗View full text ↗

Interleukin‐6 mediates exercise‐induced increase in insulin sensitivity in mice

Abstract

Full Text

You found one interesting study. We’ll send the next 7.

what lands in your inbox each week:

Recent issues from the circadian biology brief

Abstract

Full Text

Related papers

You found one interesting study. We’ll send the next 7.

what lands in your inbox each week:

Recent issues from the circadian biology brief