Endocrine Abstracts

Background and Aim: Unacylated ghrelin (UAG) is the major form of circulating ghrelin. Initially considered as a non-functional peptide, soon after UAG has been associated to a negative action on energy balance, suppression of hepatic glucose production and decrease in circulating levels of insulin. The aim of this study was to analyze the association between the serum levels of UAG and glucose metabolism parameters in obese women, independently from the eventual interference of adiposity.

Material and Methods: One hundred lean and 254 obese Caucasian women were studied. Each woman was characterized for total body weight, body mass index (BMI), waist and hip circumferences, glucose at fasting and 2 hours after an oral glucose tolerance test (OGTT), fasting insulin, glycated hemoglobin (HbA1c), and UAG. Insulin resistance was assessed by the homeostasis model assessment (HOMA-IR). Obese women were classified in three glycemic status subgroups (normoglycemia, prediabetes and diabetes) according to HbA1c and glucose values.

Results: When compared with the lean group, significantly lower UAG levels were observed in obese women when compared with the lean group (350.2±251.9 vs 219.2±149.7 pg/ml; P<0.001). However, no significant difference was observed through obesity classes I to III. UAG levels were not significantly different among glycemic status subgroups and did not show any direct association with glucose, insulin, HOMA-IR, or HbA1c values.

Conclusions: Although the level of the unacylated form of ghrelin shows an association with anthropometrics it seems not to be involved in glucose homeostasis.