Losartan may prevent the elevation of plasma glucose, corticosterone and catecholamine levels induced by chronic stress.
BACKGROUND
Stress is a stimulus that activates the hypothalamic pituitary adrenal (HPA) axis and sympathetic nervous system (SNS). Increased activity of the SNS causes to increment or impairment in blood pressure, heart rate, body temperature and plasma glucose and adreno- corticotrophic hormone (ACTH) levels. Angiotensin II (Ang II), which is a product of the renin-angiotensin system (RAS), is an important factor affecting the activity of the SNS and responses to stress. We suggest that the blockade of Ang II may be worthwhile in the prevention and treatment of diabetes mellitus and cardiovascular diseases affected by stress. Therefore, we investigated the effects of immobilisation stress on blood glucose, norepinephrine (NE), epinephrine (E) and corticosterone levels and the effects of an Ang II receptor antagonist, losartan, on these parameters.


METHODS
The rats were kept in small cylindrical cages for 60 min/day for 10 consecutive days to perform chronic immobilisation stress. Losartan (10 mg/kg) was given daily by gavage to Losartan (L) and Losartan + Chronic Stress (L+CS) groups. Control (C) and Chronic Stress (CS) groups received an equal volume of saline daily by gavage for 10 days. After the last stress regimen, blood samples were collected for plasma glucose, NE, E and corticosteroid measurements.


RESULTS
Plasma glucose, NE, E and corticosterone levels in the CS Group increased significantly compared with the C group. In Group L+CS, the plasma glucose, NE, E and corticosterone levels decreased significantly vs. Group CS. In Group L there was no significant difference vs. Group C.


CONCLUSIONS
It can be speculated that chronic blockade of RAS may decrease the excess sympathetic responses to stress in cardiovascular diseases and prevent the likely development of Type II diabetes mellitus.
Istanbul Faculty of Medicine, Department of Pharmacology and Clinical Pharmacology, Istanbul University, Capa, Turkey. yagiz@istanbul.edu.tr
Yağiz
Y
Uresin
Bahar
B
Erbas
Mehmet
M
Ozek
Elif
E
Ozkök
Ali Osman
AO
Gürol
D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001786:Blood Glucose / Q000187:drug effects*; D002908:Chronic Disease; D003345:Corticosterone / Q000097:blood; D004837:Epinephrine / Q000097:blood; D006943:Hyperglycemia / Q000097:blood / Q000188:drug therapy* / Q000209:etiology; D019808:Losartan / Q000494:pharmacology*; D008297:Male; D009638:Norepinephrine / Q000097:blood; D051381:Rats; D017208:Rats, Wistar; D012149:Restraint, Physical; D013312:Stress, Physiological / Q000097:blood / Q000150:complications / Q000188:drug therapy*
D000959:Antihypertensive Agents; D001786:Blood Glucose; D019808:Losartan; D003345:Corticosterone; D009638:Norepinephrine; D004837:Epinephrine