The roles of ghrelin/agouti-related protein/peptide YY signal pathway in gastric bypass operation for type 2 diabetes

Abstract

Objective To study the roles of ghrelin, agouti-related protein (AGRP) and peptide YY(PYY) signal in treatment of type 2 diabetes mellitus by gastric bypass operation. Methods Twenty adult SD rats were used to establish the model of type 2 diabetes mellitus, and divided into 2 groups: No operation group (NO, n=10) and Roux-en-Y gastric bypass operation group (RYGB, n=10), and another ten adult rats were used as the Normal Control group (NC, n=10). The RYGB group were performed operation after the rat model of type 2 diabetes mellitus were established successfully. The blood were separately collected to examine ghrelin, blood sugar, cholesterol and triglyceride before and after operation, and we monitored the consumption of food and water everyday. The hypothalamus tissues were collected at the 4th week after operation to examine the expression of AGRP and PYY mRNA. Results At the 4th week after operation, the blood sugar dropped to (6.18±0.77) mmol/L, Triglycerides dropped to (2.45±0.23) mmol/L; Cholesterol dropped to (2.07±0.22) mmol/L and the consumption of food, water of RYGB group were nearly down to normal level. The level of ghrelin dropped to (410.60±58.33) ng/L, AGRP mRNA dropped to 0.80±0.13 in hypothalamus were lower than NO group after operation, the level of PYY mRNA rised to 1.60±0.25 were significantly increased (P<0.05). Conclusion We can conclude that the situation of type 2 diabetes mellitus can be controlled by Roux-en-Y gastric bypass operation. Ghrelin may regulate the energy metabolism of type 2 diabetes mellitus via AGRP and PYY signals. Our results suggest that the roles of ghrelin, AGRP and PYY signals may play an important role in the control of type 2 diabetes mellitus after Roux-en-Y gastric bypass operation. Key words: Ghrelin; Agouti-related protein; Peptide YY; Gastric bypass operation; Type 2 diabetes mellitus