Gastrointestinal histamine and histamine formation capacity after gastric irradiation in mice.
Mice were exposed to a single dose of 9 or 15 Gy of X rays directed to the stomach. Histamine and histamine formation capacity (HFC) in the oxyntic region of the stomach were assayed at regular intervals for 7 weeks. After 9 Gy, mean gastric mural histamine fell to 61% of the control value (p less than 0.01) 7 days after irradiation while HFC rose to 172% (p less than 0.05). Both histamine and HFC returned to control values within 2 weeks after irradiation. With 15 Gy, on Day 7, histamine fell to 46% (p less than 0.01) and HFC rose to 260% (p less than 0.05). Histamine concentration remained low (less than half of the control value) while HFC returned to normal. These dose-dependent changes in histamine were observed neither elsewhere in the gut nor in the circulating blood. Further groups of mice were exposed to 3, 6, 9 or 15 Gy to the stomach, with gastric histamine and HFC assayed on Day 7. Histamine concentration was inversely related to dose (r = -0.59, p less than 0.001) and HFC was directly dose dependent (r = 0.52, p less than 0.001). These results suggest that irradiation of the stomach may reduce gastric histamine without inducing a general histamine release. The depletion of the gastric histamine store may explain the inhibitory effect of irradiation of the stomach on gastric acid secretion.
Man
W K
WK
Department of Surgery, Royal Postgraduate Medical School, Hammersmith Hospital, London.
Li
S K
SK
Spencer
J
J
Baron
J H
JH
Michalowski
A S
AS
D000818:Animals; D002262:Carboxy-Lyases / Q000378:metabolism*; D003106:Colon / Q000378:metabolism; D004307:Dose-Response Relationship, Radiation; D004386:Duodenum / Q000378:metabolism; D004947:Esophagus / Q000378:metabolism; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism; D006632:Histamine / Q000378:metabolism*; D006640:Histidine Decarboxylase / Q000378:metabolism*; D007082:Ileum / Q000378:metabolism; D051379:Mice; D008815:Mice, Inbred Strains; D013270:Stomach / Q000528:radiation effects*; D013997:Time Factors
D006632:Histamine; D002262:Carboxy-Lyases; D006640:Histidine Decarboxylase