title: Capsiate improves glucose metabolism by improving insulin sensitivity better than capsaicin in diabetic rats.
abstract: Red peppers and red pepper paste are reported to have anti-obesity, analgesic and anti-inflammatory effects in animals and humans due to the capsaicin in red pepper. We investigated whether consuming capsaicin and capsiate, a nonpungent capsaicin analogue, modifies glucose-stimulated insulin secretion, pancreatic β-cell survival and insulin sensitivity in 90% pancreatectomized (Px) diabetic rats, a moderate and non-obese type 2 diabetic animal model. Px diabetic rats were divided into 3 treatment groups: 1) capsaicin (Px-CPA), 2) capsiate (Px-CPI) or 3) dextrose (Px-CON) and provided high fat diets (40 energy % fat) containing assigned components (0.025% capsaicin, capsiate, or dextrose) for 8 weeks. Both capsaicin and capsiate reduced body weight gain, visceral fat accumulation, serum leptin levels and improved glucose tolerance without modulating energy intake in diabetic rats. In comparison to the control, both capsaicin and capsiate potentiated first and second and phase insulin secretion during hyperglycemic clamp. Both also increased β-cell mass by increasing proliferation and decreasing apoptosis of β-cells by potentiating insulin/IGF-1 signaling. However, only capsiate enhanced hepatic insulin sensitivity during euglycemic hyperinuslinemic clamp. Capsiate reduced hepatic glucose output and increased triglyceride accumulation in the hyperinsulinemic state and capsiate alone significantly increased glycogen storage. This was related to enhanced pAkt→PEPCK and pAMPK signaling. Capsaicin and capsiate reduced triglyceride storage through activating pAMPK. In conclusion, capsaicin and capsiate improve glucose homeostasis but they differently enhance insulin sensitivity in the liver, insulin secretion patterns, and islet morphometry in diabetic rats. Capsiate has better anti-diabetic actions than capsaicin.
authors.affiliation: Food Functional Research Division, Korean Food Research Institutes, Sungnam 463-746, Korea.
authors.forename: Dae Young
authors.initials: DY
authors.lastname: Kwon
authors.forename: Youg Sup
authors.initials: YS
authors.lastname: Kim
authors.forename: Shi Yong
authors.initials: SY
authors.lastname: Ryu
authors.forename: Mi-Ran
authors.initials: MR
authors.lastname: Cha
authors.forename: Gyu Hwan
authors.initials: GH
authors.lastname: Yon
authors.forename: Hye Jeong
authors.initials: HJ
authors.lastname: Yang
authors.forename: Min Jung
authors.initials: MJ
authors.lastname: Kim
authors.forename: Sunna
authors.initials: S
authors.lastname: Kang
authors.forename: Sunmin
authors.initials: S
authors.lastname: Park
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D002211:Capsaicin / Q000031:analogs & derivatives* / Q000494:pharmacology; D002470:Cell Survival; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy / Q000378:metabolism*; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy / Q000378:metabolism; D015309:Glucose Clamp Technique; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D007328:Insulin / Q000097:blood / Q000378:metabolism; D007333:Insulin Resistance; D050417:Insulin-Secreting Cells / Q000187:drug effects / Q000378:metabolism; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D001786:Blood Glucose; D007004:Hypoglycemic Agents; D007328:Insulin; C470213:capsiate; D002211:Capsaicin