Endocrine Abstracts

Orlistat and Metformin have both been shown to be beneficial in the treatment of Polycystic Ovarian Syndrome (PCOS), however, because Orlistat works by decreasing the absorption of dietary lipids, there is the potential to decrease absorption of lipophilic antioxidant substances with consequent decreased protection from oxidative stress. The objective of this study was to evaluate and compare the effect of treatment with orlistat vs. metformin on oxidative stress in patients with polycystic ovarian syndrome.

Twenty Caucasian women with PCOS [mean (±S.E.M.) age 27±0.9 yr and body mass index 36.7±3.3 kg/m²] participated in this prospective, randomized, open-labeled study. All subjects had an 8-wk run-in period of dietary modification and then randomized to receive either metformin n=10 (500 mg three times daily) or orlistat n=10 (120 mg three times daily) for 3 months. Fasting blood samples were taken at randomisation and on completion¹. Malondialdehyde, (MDA) used as a marker of oxidative stress, was measured in fasting plasma samples taken at randomisation and on completion.

There was a significant reduction in weight with orlistat and a reduction in androgen levels in both groups and a trend to a reduction in insulin resistance¹. When compared with baseline, treatment with both orlistat (mean±S.E.M.) [0.61±0.06 umol/l vs. 0.61 umol/l±0.04, P=0.99] and metformin [0.711±0.067 umol/l vs. 0.74±0.085 umol/l, P=0.69] produced no significant change in oxidative stress as assessed using MDA.

The reduction in weight and androgen levels by Orlistat and Metformin are not associated with changes in oxidative stress in patients with PCOS.

1. Jayagopal V et al. J Clin Endocrinol Metab 90: 729–733, 2005 .