Response of shell-less cultured chick embryos to exogenous parathyroid hormone and 1,25-dihydroxycholecalciferol

Abstract

Chick embryos maintained in shell-less culture up to a total age of 14 days and 11-day-old embryos developed in ovo were injected either with 20 USP units parathyroid hormone or with 200 pmol 1,25-dihydroxycholecalciferol. In all cases, a significant increase in the concentration of calcium in blood was observed. Since in the cultured embryos the shell is absent, no calcium can reach the embryo through the chorioallantoic membrane; the present results are thus interpreted as meaning that both parathyroid hormone and 1,25-dihydroxycholecalciferol can produce their effect by acting on target organs other than the chorioallantoic membrane.