Preptin is an endocrine
peptide secreted from pancreatic β cells; it acts as a physiological amplifier of
glucose-mediated insulin secretion.
Osteocalcin, secreted by osteoblasts, is also involved in the regulation of body energy in that it modulates fat and
glucose metabolism. The aim of this study was to investigate circulating
preptin and
osteocalcin levels and the possible association between them in obese and
overweight adults. A total of 100 obese-
overweight adults and 50 healthy controls matched for age and sex were enrolled in this study. Anthropometric measurements were taken and fasting
glucose,
insulin, homeostasis model assessment of
insulin resistance (HOMA-IR),
lipid profile,
preptin, and
osteocalcin were assessed.
Preptin was significantly higher in obese and
overweight subjects than in controls, whereas
osteocalcin was significantly lower. In multiple regression analysis,
preptin was independently influenced by waist circumference (WC) (β = 3.75, P = 0.03), fasting
insulin (β = 4.77, P = 0.01), HOMA-IR (β = 8.21, P = 0.003), and
osteocalcin (β = -28.41, P = 0.04).
Osteocalcin was independently influenced by body mass index (β = -1.46, P = 0.05), WC (β = -2.04, P = 0.03), fasting
insulin (β = -2.69, P = 0.02), HOMA-IR (β = -0.19, P = 0.006), and
triglyceride (β = -4.54, P = 0.001). In conclusion, elevated serum
preptin and decreased
osteocalcin concentrations, together with
insulin resistance, are associated with
obesity and
overweight. Serum
preptin is also independently associated with
osteocalcin, which may explain, at least in part, the crosstalk between bone and the β cells of the pancreas.