OBJECTIVE: The syndrome of polycystic ovaries (PCOS) is a known risk factor for type 2 diabetes. It is not known, however, whether the increase in diabetes risk is related to endocrine abnormalities associated with PCOS such as hyperandrogenemia, or whether it is a consequence of the anthropometric or metabolic alterations frequently observed in PCOS women. DESIGN: Since markers of inflammation are supposed to predict type 2 diabetes, interleukin-6 (IL-6) and C-reactive protein (CRP) in combination with parameters of obesity, insulin resistance and hyperandrogenism were determined in 57 PCOS women and in 20 age-matched healthy controls. In addition, the C-174G IL-6 promoter polymorphism was analyzed as a determinant in influencing IL-6, obesity, and androgen levels in women. RESULTS: Neither CRP nor IL-6 were significantly elevated in lean or obese PCOS women compared with age-matched lean or obese controls. In PCOS patients, variables of body composition (body mass index (BMI), waist to hip ratio, dual-energy X-ray-absorptiometry fat mass) and of insulin resistance were correlated with IL-6 or CRP, while parameters of hyperandogenism were not. Multivariate linear regression analysis revealed that obesity is the dominant force, thus explaining 18% and 24% of the IL-6 or CRP levels, respectively, in PCOS women. No association of IL-6 or BMI to a certain genotype at C-174G could be demonstrated in 50 PCOS patients. The heterozygous GC genotype, however, was associated with lower androstendione levels. Metformin treatment of 9 obese, insulin-resistant PCOS patients over a period of 6 months caused a significant decrease in body weight, body fat mass and total testosterone, but showed no significant decline in IL-6 or CRP concentrations. CONCLUSIONS: In PCOS women, plasma levels of IL-6 and CRP were not increased when compared with age- and BMI-matched controls. BMI was, however, the parameter most strongly related to IL-6 and CRP in PCOS; thus PCOS-related endocrine abnormalities do not appear to activate inflammatory parameters thereby enhancing the risk of diabetes. In PCOS, the type 2 diabetes risk may, therefore, be confined to those with obesity and/or metabolic alterations rather than affecting all women suffering from the syndrome.
M Mohlig, J Spranger, M Osterhoff, M Ristow, AF Pfeiffer, T Schill, HW Schlosser, G Brabant and C Schofl
M A Arafat, B Otto, H Rochlitz, M Tschöp, V Bähr, M Möhlig, S Diederich, J Spranger and A F H Pfeiffer
Objective: It is well known that i.m. glucagon administration stimulates GH and cortisol release in humans, although the mechanisms are unclear. These effects are similar to those described for ghrelin on somatotroph and corticotroph function. The aim of the present study was to investigate the role of ghrelin in mediating the stimulatory effects of glucagon and to evaluate the effect of glucagon on ghrelin secretion.
Design and methods: We studied the endocrine and metabolic response to i.m. glucagon administration in 24 subjects (14 men, 10 women; age 19–65 years; body mass index, 25.3 ± 1 kg/m2), who were shown to have an intact anterior pituitary function as evaluated before enclosure.
Results: Serum ghrelin concentrations fell significantly at 30, 60, 120 and 180 min after glucagon administration (means ± s.e.m.; baseline, 377.9 ± 34.5 pg/ml; nadir, 294.6 ± 28.3 pg/ml (60 min); P < 0.01). Conversely, i.m. glucagon elicited an increase in GH (baseline, 1.5 ± 0.4 μg/l; peak, 14.2 ± 2.7 μg/l (180 min); P < 0.01) and cortisol concentrations (baseline, 452.6 ± 35.2 nmol/l; peak, 622.1 ± 44 nmol/l (180 min); P < 0.01). The changes in ghrelin concentration at both 120 and 180 min were still significant after correction for glucose and insulin (P < 0.05).
Conclusions: We show that i.m. glucagon decreases ghrelin significantly. Therefore, the already known stimulatory effects of i.m. glucagon on cortisol and GH are not mediated by a change in ghrelin concentrations. The mechanisms underlying the ghrelin suppression after i.m. glucagon are unlikely to include glucose or insulin variations and need to be further elucidated.