Diet‐induced Changes in Sex Hormone Binding Globulin and Free Testosterone in Women With Normal or Polycystic Ovaries: Correlation With Serum Insulin and Insulin‐like Growth Factor‐i

Abstract

The purpose of this study was to investigate the effect of calorie restriction on serum concentrations of sex hormone binding globulin (SHBG) in women with normal or polycystic ovaries (PCO) and to examine the possible role of insulin and insulin-like growth factor-I (IGF-I) in mediating changes in SHBG levels. Six normal subjects with mean (SD) body mass index (BMI) 25.5 (2.2) and five subjects with PCO (BMI 36.1 (3.7)) were studied before and after 2 or (PCO only) 4 weeks of a very low calorie diet (330 kcal/day; Cambridge Diet). In both normal women and patients with PCO there was a twofold increase in SHBG concentrations after 2 weeks and this was sustained in the PCO subjects for a further 2 weeks. The rise in SHBG was accompanied by a fall in free testosterone concentrations. There were parallel changes in serum insulin and IGF-I concentrations which decreased during the diet and there were significant negative correlations of SHBG with insulin in both normal subjects (r = -0.62) and women with PCO (r = -0.60). In addition, serum concentrations of an insulin-dependent small molecular weight (34 kDa) binding protein for IGF-I (IGF-BPI) increased significantly during dieting in both groups and were negatively correlated with serum insulin (controls, r = -0.56; PCO, r = -0.68) and positively correlated with serum SHBG levels (controls, r = 0.69; PCO, r = 0.63). In summary, these data indicate that in both normal subjects and those subjects with PCO, calorie restriction results in a highly significant increase in SHBG concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of metformin or orlistat on obese women with polycystic ovary syndrome: a prospective randomized open-label study

“…In our study treatment with orlistat did not significantly reduce LH level. Weight reduction in PCOS has been reported to improve hyperinsulinemia [36,[47][48][49], and reduce serum LH level [50]. Metformin and the other insulin sensitizing agents interact on different levels of insulin physiology.…”

Endogenous 6-Hydroxymelatonin Excretion and Subsequent Risk of Breast Cancer: A Prospective Study

“…Recent studies have observed the efficacy of changes in diet and in lifestyle in improving insulin sensitivity and reducing the availability of sex honrmones [63][64][65][66][67][68][69][70][71][72][73]. These studies may indicate possible strategies for future breast cancer prevention.…”

Polycystic Ovary Syndrome and Cardiovascular Disease

“…Weight reduction decrease circulating androgen levels and restart the menstrual cycle (Guzick, Wing et al 1994;Okajima, Koyanagi et al 1994;Clark, Ledger et al 1995).These alterations can be obtained with a weight loss as small as 5% of the initial weight (Franks, Kiddy et al 1991;Kiddy, Hamilton-Fairley et al 1992). Additional advantages that have been reported to have lowered circulating insulin levels (Kiddy, Hamilton-Fairley et al 1989;Kiddy, HamiltonFairley et al 1992). The reduction of free testosterone concentrations, subsequent weight loss mostly mediated through increases by SHBG (Franks, Kiddy et al 1991;Kiddy, HamiltonFairley et al 1992).…”