AJP - Endocrinology and Metabolism, Vol 248, Issue 1 80-E88, Copyright © 1985 by American Physiological Society
PGE2 binding, synthesis, and distribution in hen oviduct
G. Asboth, H. Todd, M. Toth and F. Hertelendy
Prostaglandin E2 (PGE2) bound specifically to particulate fractions
prepared from the vagina and uterus (shell gland) portions of the hen
oviduct in a time and temperature dependent fashion. Scatchard analysis
indicated a single class of high-affinity binding sites in the vagina (Kd
congruent to 1 nM), whereas the myometrium exhibited two kinds of binding
site populations (Kd1 congruent to 1 nM, Kd2 congruent to 20 nM). It is
suggested that these binding sites represent specific PGE2 receptors
mediating the effects of PGE2 in oviductal smooth muscle. Vaginal
particulate fractions produced approximately four times more prostanoids
from [3H]-arachidonate than did uterine preparations. In the presence of
epinephrine both tissues synthesized mainly thromboxane (TxB2), PGE2, and
significantly less prostaglandin F2 alpha (PGF2 alpha). Addition of
glutathione (GSH) or cytosol prepared from the oviduct markedly increased
the yield of PGE2 at the expense of TxB2. Of the five morphologically
discrete regions of the oviduct the vagina, infundibulum, and uterus
contained the highest amounts of PGE and PGF, whereas the magnum and
isthmus portions contain the least. TxB2 and 6-keto PGF1 alpha could not be
detected in significant quantities in either region. These studies support
the notion that PGE2 play a key role in the physiology of oviposition.
