Melatonin inhibits the regulation of hypothalamo-pituitary-adrenal axis in diabetic rats / 第二军医大学学报

ABSTRACT

Objective: To study the effect of melatonin (Mel) , a potent antioxidant, on the oxidative stress and the activity of hypothalamo-pituitary-adrenal axis in diabetic rats. Methods: Male SD rats were assigned to the following 4 groups normal control (treated with 2% ethyl alcohol lavage[ NC, n=6 ]), diabetes mellitus control (treated with 2% ethyl alcohol lavage [DM, n=7]), diabetes mellitus model group 1 (treated with Mel lavage [10 mg · kg-1 d-1, DM+Mell, n=61), diabetes mellitus model group 2 (treated with Mel lavage [0. 2 mg · kg-1 · d-1 , DM+Me2, n=61). Diabetes in DM group, DM+Mell group and DM+Mel2 group was induced by intraperitoneal injection of streptozotacin (65mg/kg). Blood glucose, body weight and adrenal gland weight/body weight(AW/BW) were determined in the 4 groups 12 weeks later; malondialdehyde (MDA) was examined with visible spectrophotometry; blood total cholesterol (TC) and triglyceride (TG) were examined with enzymology method; blood corticotrophin-releasing hormone (CRH), adreno-corticotrophic hormone(ACTH) and corticosterone(CORT) were examined with radioimmune method. Results: Blood glucose, MDA , TC, TG, CRH, ACTH, CORT and AW/BW in DM group were significantly higher than those in NC group (P<0.01); and the body weight of rats in DM group were significantly lower those of NC group(P<0.01). Compared with DM group, DM+Mel1 and DM+Mel2 group had a significantly lower blood glucose, MDA TC, TG and AW/BW (P<0.01 or Pbody weight (P<0.01). Blood CRH, ACTH and CORT were markedly decreased in DM+Mel2 group(P<0.01); blood CORT were markedly decreased in DM+Mel2 group (P<0.05); blood CRH and ACTH in DM+Mel2 group had no significant changes.

Conclusion:

Mel may lower the oxidase activity, improve metabolic disorder of glucose and fat, and inhibit the activity of hypothalamo- pituitary- adrenal axis in diabetic rats, exerting protective effect on diabetic rats.