Obese but not normal-weight women with polycystic ovary syndrome are characterized by metabolic and microvascular insulin resistance.

Abstract

CONTEXT:

Polycystic ovary syndrome (PCOS) and obesity are associated with diabetes and cardiovascular disease, but it is unclear to what extent PCOS contributes independently of obesity.

OBJECTIVE:

The objective of the study was to investigate whether insulin sensitivity and insulin's effects on the microcirculation are impaired in normal-weight and obese women with PCOS.

DESIGN AND POPULATION:

Thirty-five women with PCOS (19 normal weight and 16 obese) and 27 age- and body mass index-matched controls (14 normal weight and 13 obese) were included. Metabolic Insulin sensitivity (isoglycemic-hyperinsulinemic clamp) and microvascular insulin sensitivity [endothelium dependent (acetylcholine [ACh])] and endothelium-independent [sodium nitroprusside (SNP)] vasodilation with laser Doppler flowmetry was assessed at baseline and during hyperinsulinemia.

MAIN OUTCOME MEASURES:

Metabolic insulin sensitivity (M/I value) and the area under the response curves to ACh and SNP curves were measured to assess microcirculatory function at baseline and during insulin infusion (microvascular insulin sensitivity).

RESULTS:

Obese women were more insulin resistant than normal-weight women (P < 0.001), and obese PCOS women were more resistant than obese controls (P = 0.02). In contrast, normal-weight women with PCOS had similar insulin sensitivity, compared with normal-weight women without PCOS. Baseline responses to ACh showed no difference in the four groups. ACh responses during insulin infusion were significantly greater in normal-weight PCOS and controls than in obese PCOS and controls. PCOS per se had no significant influence on ACh responses during insulin infusion. During hyperinsulinemia, SNP-dependent vasodilatation did not significantly increase, compared with baseline in the four groups.

CONCLUSION:

PCOS per se was not associated with impaired metabolic insulin sensitivity in normal-weight women but aggravates impairment of metabolic insulin sensitivity in obese women. In obese but not normal-weight women, microvascular and metabolic insulin sensitivity are decreased, independent of PCOS. Therefore, obese PCOS women in particular may be at increased risk of metabolic and cardiovascular diseases.

• Authors: Iris J G Ketel, Coen D A Stehouwer, Erik H Serné, Ted J M Korsen, Peter G A Hompes, Yvo M Smulders, Renate T de Jongh, Roy Homburg, Cornelis B Lambalk
• Journal: The Journal of clinical endocrinology and metabolism (J Clin Endocrinol Metab) Vol. 93 Issue 9 Pg. 3365-72 (Sep 2008) ISSN: 0021-972X [Print] United States
• PMID: 18593766 (Publication Type: Controlled Clinical Trial, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Insulin
• Nitroprusside

Topics

• Adult
• Blood Pressure (drug effects)
• Blood Vessels (drug effects, physiology)
• Body Weight (physiology)
• Endothelium, Vascular (drug effects)
• Female
• Humans
• Insulin (administration & dosage, pharmacology)
• Insulin Resistance (physiology)
• Nitroprusside (pharmacology)
• Obesity (complications, metabolism, physiopathology)
• Polycystic Ovary Syndrome (complications, metabolism, physiopathology)
• Skin (blood supply, drug effects)
• Vasodilation (drug effects)