Countercurrent exchange of progesterone and antipyrine between human utero-ovarian vessels, and of antipyrine between the femoral vessels in the cat.

The utero-ovarian vein and ovarian artery in surgical specimens were cannulated and perfused in a countercurrent manner with isotonic, buffered solutions, fortified on the venous side with progesterone or radiolabelled methylantipyrine. Both substances were gradually transferred from the vein into the artery in the majority of the experiments while albumin was not exchanged. The results point to the existence of a countercurrent exchange mechanism in the human ovarian pedicle. Hardly detectable amounts of methylantipyrine were transferred from femoral vein to artery in the cat.