AJP - Gastrointestinal and Liver Physiology, Vol 256, Issue 2 328-G334, Copyright © 1989 by American Physiological Society
Bombesin ingestion stimulates epithelial digestive cell proliferation in suckling rats
F. Puccio and T. Lehy
Unite de Recherche de Gastroenterologie, Institut National de la Sante et de la Recherche Medicale U. 10, Hopital Bichat, Paris, France.
The characterization of a bombesin-like peptide in the breast milk of some
mammals might suggest that this peptide may influence, in part, the
postnatal development of the digestive tract. To test this hypothesis, our
experiments investigated whether oral administration of bombesin affects
epithelial progenitor cell proliferation in digestive organs of suckling
and weaned rats. Four series of pups were given bombesin diluted in milk
(20 micrograms/kg, 3 times daily) or milk alone, for 5 days during either
the first, second, third, or fourth week of life. Pups were killed after
[3H]thymidine pulse labeling. DNA labeling and mitotic indices were
estimated in the oxyntic, antral, colonic mucosae, and exocrine pancreas.
In all tissues examined, oral bombesin significantly increased over control
values the two cell proliferative parameters studied during the suckling
period (P less than 0.05 to P less than 0.001). In bombesin-treated rats,
maximal stimulation of these parameters occurred in the second week of
life. This effect of oral bombesin on the cell kinetics disappeared in all
tissues after weaning. This study confirms the growth-promoting effect of
bombesin observed on the digestive system of the neonatal rat after
subcutaneous administration of the peptide and shows that bombesin, when
given orally to suckling rats, is sufficiently resistant to proteolysis to
enable it to exert a stimulatory effect on digestive cell proliferation.
However, our findings as such do not prove that milk bombesin-like peptide
has a physiological influence on the developing gastrointestinal tract and
pancreas.
