Kooh S W
Can J Physiol Pharmacol. 1980 Aug;58(8):934-9. doi: 10.1139/y80-142.
Responsiveness of the sheep fetus to parathyroid hormone (PTH) infusion was studied in the unanesthetized fetus in situ and the results were compared with those obtained in the newborn lamb, PTH, 0.5 USP U/min per kilogram body weight was infused intravenously to four sheep fetuses in utero (gestational age 127-141 days) and 10 newborn lambs (1-20 days of age). PTH infusion increased plasma Ca in the fetus and the PTH-induced hypercalcemia increased plasma calcitonin although the maternal levels of Ca and calcitonin did not change. In the fetus, as well as in the newborn lamb, PTH decreased the percentage tubular reabsorption of phosphate (TRP) and increased urinary excretion of cAMP. These results indicate that the sheep fetus has developed the target organ responsiveness to PTH and a normal calcitonin secretory mechanism by the last trimester of gestation.
在未麻醉的原位绵羊胎儿中研究了其对甲状旁腺激素（PTH）输注的反应性，并将结果与新生羔羊的结果进行了比较。以0.5 USP U/（分钟·千克体重）的剂量将PTH静脉输注到4只子宫内的绵羊胎儿（妊娠127 - 141天）和10只新生羔羊（1 - 20日龄）体内。PTH输注使胎儿血浆钙升高，且PTH诱导的高钙血症使血浆降钙素升高，尽管母体的钙和降钙素水平未发生变化。在胎儿以及新生羔羊中，PTH均降低了肾小管对磷酸盐的重吸收百分比（TRP）并增加了尿中环磷酸腺苷（cAMP）的排泄。这些结果表明，绵羊胎儿在妊娠晚期已发育出对PTH的靶器官反应性和正常的降钙素分泌机制。
