OGTT was performed in 17 healthy adult test persons (9 male and 8 female). Apart from S100B, glucose, free fatty acids, insulin, C-peptide, and cortisol were determined in all samples after an overnight fast (0 h), as well as 1 h and 2 h after ingestion of 75 g glucose.
Mean S100B concentrations decreased about 20% during the first hour after glucose ingestion (P < 0.001). This decrease of S100B levels was not related to the declining morning peak of cortisol. However, the decrease of serum-S100B 1 h after glucose ingestion correlated inversely with the respective changes of serum-insulin (r = 鈭?.484, P = 0.049) and serum-C-peptide (r = 鈭?.570, P = 0.017).
Our study suggests an inverse correlation between insulin secretion and S100B release after a standardized OGTT. Additional experiments, including the administration of insulin and the measurement of other food intake-related factors are important to ascertain an insulin-regulated S100B release in vivo. To improve comparability between clinical studies assessing conditions with rather mild changes of serum S100B, blood should be taken in a more standardized way (e.g., after fasting overnight).