Lipopolysaccharide reverses adrenocorticotrophic hormone-induced hypertension in the rat.
Lipopolysaccharide (LPS) was used to stimulate nitric oxide (NO) release and investigate the effect of endogenous NO on adrenocorticotrophic hormone (ACTH)-induced hypertension in rats. After preliminary studies to determine the appropriate dose of LPS, 40 male Sprague-Dawley rats were treated with ACTH (200 microg/kg/day, s.c.) or saline (sham) for 8 days and then given a single dose of LPS (10 mg/kg, i.p.) or saline. ACTH treatment was continued for a further 5 days. Systolic blood pressure (SBP) was measured daily using the tail cuff method. Results were expressed as the mean +/- SEM. ACTH treatment significantly increased SBP (from 105 +/- 3 to 129 +/- 4 mmHg; p<0.05), whereas saline had no effect on SBP. The ACTH-induced increase in SBP was reversed by LPS injection (from 125 +/- 6 to 102 +/- 7 mmHg; p<0.05). SBP was also decreased in sham + LPS-treated rats compared with that of sham + saline-treated rats (p<0.05), but the SBP change in response to LPS was greater in ACTH-treated than in sham-treated rats (-23 vs. -8 mmHg; p<0.05). These data are compatible with the notion that reduced NO availability plays a role in ACTH-induced hypertension.
Zhang
Yi
Y
High Blood Pressure Research Unit, John Curtin School of Medical Research, Australian National University, Canberra, Australia.
Schyvens
Christopher G
CG
McKenzie
Katja U S
KU
Morris
Brian J
BJ
Whitworth
Judith A
JA
D000324:Adrenocorticotropic Hormone / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D006973:Hypertension / Q000139:chemically induced / Q000188:drug therapy* / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
D008070:Lipopolysaccharides; D009569:Nitric Oxide; D000324:Adrenocorticotropic Hormone