GCG and hypertensive disorder: Only the history of hypertension and smoking were correlated with significantly lower levels of GLP-1 as compared with normotensive (60.1 ± 20.075 vs. 26.78 ± 5.75) and non-smokers (58.27 ± 17.13 and 22.68 ± 4.413 pmol/L, p < 0.01 and p < 0.04, respectively), but no correlation was found between GLP-1 levels and any of the clinical and laboratory parameters.