Mechanism of smoking-induced insulin resistance elucidated

Mechanism of smoking-induced insulin resistance elucidated
Smoking-induced insulin resistance, which improves with smoking cessation, may be due to activation of mammalian target of rapamycin, according to a study published online Sept. 10 in Diabetes.

(HealthDay)—Smoking-induced insulin resistance, which improves with smoking cessation, may be due to activation of mammalian target of rapamycin (mTOR), according to a study published online Sept. 10 in Diabetes.

To investigate the mechanism of smoking-induced insulin resistance, Bryan C. Bergman, Ph.D., from the University of Colorado Denver, and colleagues studied in 12 healthy sedentary nonsmokers and 10 smokers.

The researchers found that the smokers were less sensitive to insulin, but sensitivity improved after they stopped smoking for one or two weeks. The improvement was associated with normalized phosphorylation of insulin receptor substrate-1 (IRS-1) at serine 636. Treatment of muscle cells with nicotine reduced insulin sensitivity and was associated with increased phosphorylation of IRS-1 at serine 636. One of the two possible pathways known to stimulate IRS-1 phosphorylation, mTOR, was stimulated by nicotine; mTOR also prevented IRS-1 phosphorylation during and normalized insulin sensitivity when inhibited.

"These data indicate nicotine induces in skeletal muscle by activating mTOR," Bergman and colleagues conclude. "Therapeutic agents designed to oppose skeletal muscle mTOR activation may prove a novel strategy for individuals who are at increased risk of diabetes and cardiovascular disease because they cannot stop smoking or are exposed to secondhand smoke."

More information: Abstract
Full Text (subscription or payment may be required)

add to favorites email to friend print save as pdf

Related Stories

Improving obesity-induced insulin sensitivity

Jun 01, 2012

In recent years, a growing body of evidence has linked inflammation to the development of insulin resistance. In insulin resistance, the hormone insulin is less effective in promoting glucose uptake from the bloodstream into ...

How does insulin influence resistin?

Jan 16, 2008

Obesity is a worldwide health problem directly linked to several diseases such as hypertension and type 2 diabetes. Resistin is a cysteine-rich hormone mainly secreted by adipose tissues and may form a biochemical link between ...

Fewer mitochondria in offspring of parents with diabetes

Mar 26, 2012

(HealthDay) -- Normal-weight, insulin-resistant individuals whose parents have type 2 diabetes have fewer mitochondria in their muscles due to lower expression of lipoprotein lipase (LPL), according to a study ...

Insulin resistance cut-off established from clamp data

Apr 23, 2012

(HealthDay) -- Cut-offs for predicting insulin resistance based on hyperinsulinemic-euglycemic clamp data and routinely measured clinical and biochemical variables have been determined, according to a study ...

Recommended for you

Mechanism behind age-dependent diabetes discovered

Sep 17, 2014

Ageing of insulin-secreting cells is coupled to a progressive decline in signal transduction and insulin release, according to a recent study by researchers at Karolinska Institutet in Sweden. The finding, ...

User comments