Exposure to ionizing radiation modifies circulating gastrin levels and gastrointestinal endocrine cell densities in the rat.
OBJECTIVE
Gastrointestinal functions, controlled partly by gut peptides, are disturbed by ionizing radiation exposure. The effect of whole-body irradiation on circulating gastrin levels, densities of gastrointestinal endocrine cells and gastric acid secretion was investigated.


METHODS
Rats were exposed to 2 or 6 Gy gamma-radiation. They were killed 3 or 7 days later and compared with shams. Plasma gastrin and basal acid output were measured. Endocrine cells were identified by argyrophilia or immunohistochemistry and their densities estimated.


RESULTS
Radiation exposure significantly increased gastrinaemia and gastric acid output at the times studied (p<0.05-p<0.001). Endocrine cells displayed different sensitivities to irradiation. In the gastric mucosa, a 6 Gy dose induced a decrease in fundic argyrophil cell, antral gastrin and somatostatin cell densities, always accentuated 7 days after irradiation, while in the intestinal mucosa it induced an increase, with highest values often at 7 days post-irradiation (p<0.01-p<0.001). This was true for neurotensin cells in the jejunum and ileum, substance P cells in ileum and enteroglucagon cells in the descending colon.


CONCLUSIONS
Whole-body irradiation in rats significantly alters plasma gastrin levels, and several gut endocrine cell densities. This has repercussions on hormonal function, such as that exerted on acid secretion, and may explain gastrointestinal dysfunction observed following radiation exposure.
Lehy
T
T
Unité INSERM 10 de Gastroentérologie, IFR 02 Cellules Epithéliales, Hôpital Bichat-Claude Bernard, Paris, France.
Dessirier
V
V
Attoub
S
S
Bado
A
A
Griffiths
N M
NM
Linard
C
C
D000818:Animals; D019858:Enteroendocrine Cells / Q000166:cytology*; D005720:Gamma Rays; D005750:Gastric Juice / Q000378:metabolism; D005753:Gastric Mucosa / Q000166:cytology*; D005755:Gastrins / Q000097:blood*; D005768:Gastrointestinal Hormones / Q000096:biosynthesis*; D004763:Glucagon-Like Peptides / Q000378:metabolism; D007413:Intestinal Mucosa / Q000166:cytology*; D008297:Male; D009496:Neurotensin / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013373:Substance P / Q000378:metabolism; D014916:Whole-Body Irradiation
D005755:Gastrins; D005768:Gastrointestinal Hormones; D013373:Substance P; D009496:Neurotensin; D004763:Glucagon-Like Peptides