“Leptin concentrations in hirsute women with polycystic ovary syndrome or idiopathic hirsutism: influence on LH and relationship with hormonal, metabolic, and anthropometric measurements ” posted on June 26, 2001
Human Reproduction, Vol. 16, No. 7, 1340-1346, July 2001
© 2001 European Society of Human Reproduction and Embryology
Leptin concentrations in hirsute women with polycystic ovary syndrome or idiopathic hirsutism: influence on LH and relationship with hormonal, metabolic, and anthropometric measurements*
P.M. Spritzer1,2,4, M. Poy1, D. Wiltgen1,2, L.S. Mylius1 and E. Capp2,3
1 Gynecological Endocrinology Unit, Division of Endocrinology, Hospital de Clínicas de Porto Alegre,
2 Department of Physiology and
3 Department of Obstetrics and Gynecology, Universidade Federal do Rio Grande do Sul, 90.050-170, Porto Alegre, RS, Brazil
BACKGROUND: The known association between leptin, obesity and insulin action suggests that leptin may have a role in polycystic ovarian syndrome (PCOS) but this has only been addressed peripherally. METHODS: We assessed the influence of leptin on LH and investigated the relationship between leptin and body mass index (BMI), waist:hip ratio (WHR), androgen concentrations, fasting insulin and insulin:glucose ratio (IGR) in 27 women with PCOS and in 20 age- and weight-matched women with regular, ovulatory menstrual cycles and idiopathic hirsutism (IH). RESULTS: Leptin concentrations were significantly higher in obese PCOS women than in normal weight women with either PCOS or IH (P = 0.0028), but did not differ between obese women with PCOS and IH. WHR, insulin concentrations and IGR were significantly higher in obese PCOS patients in comparison with the three other groups. In IH patients, the association between leptin concentrations and WHR was lost after adjustment for BMI. In PCOS patients, a significant correlation was observed between leptin and fasting insulin concentrations, IGR, WHR and LH. After adjustment for BMI, only the correlation with LH remained significant. A stepwise regression model was set up with LH as the dependent variable to test the hypothesis that the concentrations of leptin might be modulating the concentrations of LH in PCOS patients. The relationship of LH concentrations with IGR was found to be BMI dependent. In contrast, leptin concentrations contributed negatively and significantly to LH concentrations, independently of either BMI or IGR. CONCLUSIONS: We speculate that the known attenuation in basal or stimulated response of LH in obese PCOS patients might be related to leptin resistance, which could influence LH hypersecretion. In IH ovulatory patients, normal LH concentrations suggest the presence of preserved regulatory mechanisms of GnRH pulsatility. Further studies are needed to specifically investigate the proposed correlation between leptin and GnRH modulation in PCOS.
Key Words: idiopathic hirsutism • insulin resistance • leptin • LH • polycystic ovary syndrome
* Presented in part as a Poster at the 81st Annual Meeting of the Endocrine Society, San Diego, CA, USA, June, 1999.
4 To whom correspondence should be addressed at: Departamento de Fisiologia, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite 500, 90 170 050 Porto Alegre, RS, Brazil. E-mail: firstname.lastname@example.org
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