Water Transport in the Cloaca of Lizards: Active or Passive?

Science  16 Oct 1970:
Vol. 170, Issue 3955, pp. 324-326
DOI: 10.1126/science.170.3955.324


The withdrawal of water from the lizard cloaca can be a passive process resulting from the colloidal osmotic pressure of the plasma proteins. The forces necessary to withdraw water from lizard urine, the forces prevailing within the cloaca in vivo, and the counterbalancing of these forces by a protein solution placed in the cloaca all are in accord with this hypothesis.