Low plasma atrial natriuretic peptide: a new piece in the puzzle of polycystic ovary syndrome.

CONTEXT

It is believed that a dysfunction in adipose tissue plays an important role in the pathogenesis of polycystic ovary syndrome (PCOS). Natriuretic peptides are hormones that regulate cardiovascular and body fluid homeostasis and adipose tissue metabolism. Natriuretic peptide levels are reduced in individuals with obesity and diabetes.

OBJECTIVE

This study aimed to investigate whether natriuretic peptide levels are altered in women with PCOS and whether they correlate with adiponectin levels or insulin sensitivity markers.

DESIGN AND SETTING

This was a cross-sectional study at a referral center in a teaching hospital.

PATIENTS OR OTHER PARTICIPANTS

We evaluated 40 patients diagnosed with PCOS according to the Rotterdam criteria and 36 control women matched for age and body mass index.

MAIN OUTCOME MEASURES

We measured serum adiponectin, plasma atrial natriuretic peptide (ANP), and plasma brain natriuretic peptide using enzyme immunoassays in both groups. We evaluated metabolic markers, such as fasting glucose, insulin, total cholesterol, high-density lipoprotein, low-density lipoprotein, and triglycerides. In addition, we calculated the homeostasis model assessment for insulin resistance index (HOMA-IR) and the lipid accumulation product (LAP) index and tested the linear correlations between these metabolic indices and the plasma ANP and serum adiponectin concentrations.

RESULTS

ANP and adiponectin were reduced in the PCOS group compared with the control group (P = 0.010 and P = 0.014, respectively). The brain natriuretic peptide concentration did not differ between the two groups (P = 0.883). There was no correlation between ANP and any of the metabolic markers. In the control group, the serum adiponectin level was inversely correlated with BMI (P = 0.011), waist circumference (P = 0.021), insulin (P = 0.013), fasting glucose (P = 0.010), homeostasis model assessment for insulin resistance index (P = 0.007), and lipid accumulation product (P = 0.022). Remarkably, none of these correlations were observed in the women with PCOS.

CONCLUSION

Women with PCOS had lower ANP and adiponectin compared with controls matched for age and BMI. Thus, the mechanisms that affect ANP and adiponectin production and clearance may be altered in PCOS, regardless of adiposity. These hormones may be involved in the metabolic features of PCOS.