AJP - Gastrointestinal and Liver Physiology, Vol 243, Issue 6 469-G474, Copyright © 1982 by American Physiological Society
Mucosal gastrin receptor. VIII. Sex-related differences in binding
L. R. Johnson, W. Peitsch and K. Takeuchi
The purpose of the current study was to determine whether gastrin binding
differed between the sexes and, if so, to ascertain the factors
responsible. Male and female rats were killed at various times from 15 to
60 days after birth. Binding capacities in male and female rats were equal
until puberty. By day 40 there were significantly more receptors present in
males than females. Females had 2.4 fmol receptor/mg prot by day 40, and
this value remained constant into adulthood. In male rats the number of
receptors continued to increase to 4.0 fmol/mg prot at day 60. Castration
did not significantly decrease the number of receptors in male rats.
Ovariectomy, however, increased the number of receptors in female rats to a
value not significantly different from male controls. Ovariectomized
females consumed more food and had higher serum gastrin levels. If
ovariectomized rats were pair fed to the level of intact females, the
number of receptors and serum gastrin levels decreased over those present
in ovariectomized rats fed ad libitum but still remained significantly
higher than those in intact females. Adrenalectomy of ovariectomized
females caused a further increase in receptor number.
