Mechanisms in the pressor effects of hepatic portal venous fatty acid infusion.
Portal venous infusion of oleate solution has pressor effects. We have examined efferent mechanisms, measured the response to sustained infusion, and determined the effect of linoleate. Eight conscious animals received concurrent infusions of prazosin or vehicle with portal venous infusion of oleate. Oleate alone increased mean arterial pressure from 109.0 +/- 4.1 to 123.0 +/- 5.8 mmHg (P = 0.02), whereas no increase in blood pressure occurred when oleate was infused with prazosin. In 10 rats, concurrent infusion of losartan had no effect on the pressor activity of portal oleate infusion. Twenty-two animals received portal oleate or vehicle as a continuous infusion for 7 days. Mean arterial pressure (126.1 +/- 2.0 vs. 107.8 +/- 2.6 mmHg, P < 0.001) and heart rate (383 +/- 5 vs. 366 +/- 5, P = 0.0257) were increased in oleate-infused animals. No differences in plasma fatty acids, glucose, insulin, pressor hormones, liver enzymes, or in vitro arterial pressor responsiveness were observed. Portal venous infusion of linoleate increased arterial pressure by 12.2 +/- 3.2 mmHg (P = 0.033). These results indicate that alpha-adrenergic activity is necessary for the acute pressor effects of portal oleate, that sustained portal oleate infusion results in persistent blood pressure elevation, and that other long-chain fatty acids besides oleate have pressor effects.
Grekin
R J
RJ
Endocrinology Section, Veterans Affairs Medical Center, Ann Arbor, Michigan, USA.
Dumont
C J
CJ
Vollmer
A P
AP
Watts
S W
SW
Webb
R C
RC
D000109:Acetylcholine / Q000494:pharmacology; D000450:Aldosterone / Q000097:blood; D057911:Angiotensin Receptor Antagonists; D000818:Animals; D001713:Biphenyl Compounds / Q000008:administration & dosage / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology*; D003345:Corticosterone / Q000097:blood; D004837:Epinephrine / Q000097:blood; D005230:Fatty Acids, Nonesterified / Q000097:blood; D006339:Heart Rate / Q000187:drug effects; D006973:Hypertension / Q000139:chemically induced / Q000503:physiopathology; D007093:Imidazoles / Q000008:administration & dosage / Q000494:pharmacology*; D007262:Infusions, Intravenous; D008099:Liver / Q000502:physiology* / Q000503:physiopathology; D019808:Losartan; D008297:Male; D009638:Norepinephrine / Q000097:blood; D019301:Oleic Acid / Q000008:administration & dosage / Q000494:pharmacology*; D010656:Phenylephrine / Q000494:pharmacology; D011169:Portal Vein / Q000502:physiology*; D011224:Prazosin / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012083:Renin / Q000097:blood; D012701:Serotonin / Q000494:pharmacology; D012969:Sodium Fluoride / Q000494:pharmacology; D013777:Tetrazoles / Q000008:administration & dosage / Q000494:pharmacology*; D013997:Time Factors
D057911:Angiotensin Receptor Antagonists; D001713:Biphenyl Compounds; D005230:Fatty Acids, Nonesterified; D007093:Imidazoles; D013777:Tetrazoles; D010656:Phenylephrine; D019301:Oleic Acid; D012701:Serotonin; D000450:Aldosterone; D012969:Sodium Fluoride; D012083:Renin; D019808:Losartan; D000109:Acetylcholine; D003345:Corticosterone; D009638:Norepinephrine; D011224:Prazosin; D004837:Epinephrine