The long term goal of this laboratory is to define the cellular mechanisms responsible for controlling the concentration of calcium in both the intracellular and extracellular milieu. In the shorter term, our purpose is to elucidate the mechanisms by which calcium is transported into organisms through cells. Specifically, we have focussed our attention on the active transport mechanisms that move calcium across epithelial cells in the embryonic chick chorioallantoic membrane CAM and the small intestine of rat and chick. BIBLIOGRAPHIC REFERENCES: Coleman, J.R. Electron Probe Studies of Calcium Transport. Proc. XI Conference Microbeam Analysis Society, pp. 58A-58H (1976). Terepke, A.R., J.R. Coleman, H.J. Armbrecht and T. Gunter. Transcellular Calcium Transport. Symp. Soc. Exp. Biol. In: Calcium in Biological Systems, edited by C.J. Duncan, Cambridge University Press (1976), pp. 117-140.