AJP - Regulatory, Integrative and Comparative Physiology, Vol 232, Issue 3 124-R127, Copyright © 1977 by American Physiological Society
Prolactin and fetal osmoregulation: water transport across isolated human amnion
E. A. Leontic and J. E. Tyson
The addition of human or ovine prolactin to the fetal side of the human
amnion is associated with a latent decrease in membrane permeability. The
specificity of this effect of prolactin is observed when equimolar
concentrations of human placental lactogen and human growth hormone were
used in place of ovine prolactin and failed to influence water transport.
Likewise, the extracellular transport of p-aminohippurate across human
amnion was unaffected by the addition of ovine prolactin. Tritiated water
transport under these circumstances, however, remained impaired. The
addition of antibody to ovine prolactin completely blocked the effect of
this polypeptide on membrane permeability. Permeability to tritiated water
remained unchanged when synthetic arginine vasopressin was added to the
fetal side of the amnion. The results imply an active role for prolactin on
water transport across human amnion. Moreover, the latent period between
the addition of the polypeptide and its subsequent influence on
permeability suggests a biologic effect of this hormone. That this effect
is related to ion transfer remains to be shown.
