Not insulin but insulin sensivity, leptin, and Cortisol are major factors regulating serum acylated ghrelin level in healthy women

It has been suggested that insulin and glucose are the most important factors for ghrelin secretion. Most of these studies were performed using total ghrelin assays, detecting two forms of ghrelin (acylated and desacyl), derived from the same peptide precursor but having different biological effects. This study was therefore designed to characterize associations between serum acylated ghrelin levels (Ghr), selected adipocytokines, hormones, and carbohydrate metabolism parameters in healthy women in stable energy metabolism. The study was performed on 32 healthy, normal-weight, non-pregnant women with normal [body mass index (BMI) 18.9–24.2 kg/m2] and stable (the difference between two measurements performed within 1 month being less than 0.5 kg) body weight, aged 22–47 yr. Leptin, Ghr, GH, IGF-I, cortisol, insulin, and glucose were measured in the early follicular phase of the menstruation cycle. Insulin sensivity was measured using quantitative insulin sensivity check index (QUICKI). Body composition was assessed by bioimpedance. We found a positive linear correlation between leptin and Ghr (r=0.375; p=0.034) and negative correlation between insulin and Ghr (r=−0.374; p=0.034). GH, IGF-I, adiponectin, and body composition parameters did not correlate with Ghr. In multiple regression analysis only QUICKI, leptin, glucose, and cortisol (positively) and age (negatively) accounted for 50% variation of Ghr. Insulin and BMI did not contribute significantly to the model. Our results suggest that in healthy women basal Ghr level is regulated by multiple factors, mainly by insulin sensivity, leptin, and adrenal glands activity. However, further studies are needed to elucidate the physiological mechanisms involved in acylated Ghr secretion.