Dissociated effects of corticotropin-releasing factor on acid secretion and blood flow.
Peripherally administered corticotropin-releasing factor (CRF) inhibits gastric acid secretion in the rat via unknown mechanisms. Because intravenous CRF can produce marked systemic hypotension, the hypothesis that its antisecretory effect is due to a reduction in gastric mucosal blood flow (MBF) was tested. Corpus MBF was measured by hydrogen gas clearance in fasted, urethan-anesthetized rats. CRF (15 nmol.kg-1.h-1 iv) had no significant effect on MBF but significantly decreased systemic blood pressure (BP) by 21.8 +/- 3.4%. This dose of CRF significantly decreased acid secretion stimulated by 40 micrograms.kg-1.h-1 pentagastrin iv but did not decrease MBF despite a 30.3 +/- 2.3% decrease in BP. To avoid the confounding effect of systemic hypotension on MBF, close gastric intra-arterial infusions were performed. CRF (1.7 nmol/h ia) had no effect on BP and did not increase MBF. CRF (3.4 nmol/h ia) slightly decreased BP without modifying MBF. In contrast, histamine (200 micrograms/h ia) significantly increased MBF by 58 +/- 11%. We conclude that 1) the peripheral antisecretory effect of CRF is not related to a decrease in MBF, 2) the maintenance of MBF during CRF-induced hypotension is not due to a direct vasodilator effect of CRF on the gastric microvasculature.
Research and Medical Services, West Los Angeles, Veterans Administration Medical Center, California 90073.
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Leung
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Guth
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D005744:Gastric Acid / Q000378:metabolism*; D005753:Gastric Mucosa / Q000098:blood supply* / Q000187:drug effects / Q000502:physiology; D006632:Histamine / Q000494:pharmacology; D008297:Male; D010418:Pentagastrin / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values; D012039:Regional Blood Flow / Q000187:drug effects; D014655:Vascular Resistance / Q000187:drug effects
D006632:Histamine; D003346:Corticotropin-Releasing Hormone; D010418:Pentagastrin