M. Ciampelli et al., Impact of insulin and body mass index on metabolic and endocrine variablesin polycystic ovary syndrome, METABOLISM, 48(2), 1999, pp. 167-172
To assess the differential impact of the insulin secretory pattern and obes
ity on the endocrinometabolic features of the polycystic ovary syndrome (PC
OS), we studied 110 PCOS women. Patients underwent a gonadotropin-releasing
hormone (GnRH) test, an oral glucose tolerance test (OGTT), and basal eval
uation of hormonal and biochemical parameters. Basal androgens end lipids,
basal and stimulated gonadotropins, insulin, and glucose levels were measur
ed. Patients were classified into four groups according to the body mass in
dex (BMI) and insulin secretion: normoinsulinemic-lean ([NL] n = 24), normo
insulinemic obese ([NO] n = 24), hyperinsulinemic lean ([HF] n = 17), hyper
insulinemic obese ([HO] n = 45). HL patients showed a higher luteinizing ho
rmone (LH) area under curve (AUC) after GnRH stimulus compared with NL pati
ents (HL v NL, 4,285 +/- 348 v 3,377 +/- 314 [U/L . 120 min, P < .05), wher
eas we failed to find a statistically significant difference in a similar c
omparison among obese subjects (HO v NO, 3,606 +/- 302 v 3,129 +/- 602 IU/L
. 120 min). A trend toward increased plasma testosterone and decreased sex
hormone-binding globulin (SHBG) was found in relation to hyperinsulinemia
and obesity, thus resulting in a higher free androgen index (FAI) in groups
HL and NO versus NL (HL, 5.54 +/- 0.51; NO, 5.64 +/- 0.49; NL, 4.13 +/- 0.
33; P < .05 and P < .01, respectively). The presence of both exaggerated in
sulin secretion and obesity resulted in a synergistic additive effect on th
e FAI in the HO group (6.81 +/- 0.34). Concerning the lipoprotein lipid pro
file, the NL group showed lower plasma triglyceride levels compared with th
e other three groups, whereas no significant differences were found for non
esterified fatty acid (NEFA) concentrations. Higher low-density lipoprotein
cholesterol (LDL-C) and very-low-density lipoprotein cholesterol (VLDL-C)
and lower high-density lipoprotein cholesterol (HDL-C) levels were found in
the obese groups compared with the lean counterparts, whereas the same par
ameters did not significantly differ in a comparison between normoinsulinem
ic and hyperinsulinemic groups. In conclusion, our data suggest an importan
t role of hyperinsulinemia in the LH response to a GnRH stimulus and an ind
ependent and synergistic additive effect of obesity and hyperinsulinemia on
the FAI in PCOS. Copyright (C) 1999 by W.B. Saunders Company.