AJP - Endocrinology and Metabolism, Vol 251, Issue 1 27-E31, Copyright © 1986 by American Physiological Society
Rat visceral yolk sac: a target for parathyroid hormone action
B. Gugi, C. Silve and M. Garabedian
The stimulation of cAMP production by parathyroid hormone [human
PTH-(1-34)] in fetal membranes was studied over the last 9 days of
pregnancy in the rat. PTH significantly stimulated cAMP production in the
placental and capsular parts of the visceral yolk sac at all days studied.
In contrast PTH stimulated cAMP production in the amnion only at days 14
and 17 and had no effect in the maternal and fetal sides of the placenta
nor in the parietal yolk sac before it degenerated (day 14). The
biochemical characteristics of PTH-stimulated cAMP production in visceral
yolk sac are similar to those reported in other systems: a) maximal
stimulation was obtained with 1.2 X 10(-7) M hPTH-(1-34) and 50%
stimulation achieved by 2-3 X 10(-8) M; and b) the antagonist
[Nle8,Nle18,Tyr34] bovine PTH-(3-34) amide competitively inhibited the
stimulation of cAMP production by hPTH-(1-34). These results strongly
suggest that the rat visceral yolk sac is a target organ for PTH during the
last 9 days of pregnancy.
