Pioglitazone appears to augment insulin sensitivity in overweight patients with type 2 diabetes by suppressing plasma levels of free fatty acids, reported Dr. Mireille J. Serlie of the Academic Medical Center, Amsterdam, and her associates.
“Our results indicate that dietary interventions aimed at lowering plasma-free fatty acids may be necessary to achieve the best effect of pioglitazone on peripheral insulin sensitivity,” the investigators said (J. Clin. Endocrin. Metab. 2006 Oct. 24 [Epub doi:10.1210/jc.2006–1518]).
Dr. Serlie and her associates studied the issue in 8 overweight patients with type 2 diabetes that was moderately controlled on a single oral medication. Patients were allowed to take statins (but not fibrates) and antihypertensive drugs. All patients served as their own controls.
The six men and two postmenopausal women took pioglitazone 30 mg/day for 4 months, which enhanced insulin sensitivity and significantly lowered plasma free fatty acid levels. When these levels were then induced to rise to pretreatment levels during an experiment, pioglitazone's insulin-sensitizing effect was nullified, the researchers said.
This study shows that lowering plasma levels of free fatty acids “is crucial in the insulin-sensitizing effect of pioglitazone,” they noted.
Dr. Serlie reported no conflicts of interest. Co-author Hans P. Sauerwein reported receiving lecture fees from Eli Lilly & Co., which provided the drug used in the study.