GRAFTS OF OVARIAN MEDULLARY TISSUE IN THE RABBIT

SUMMARY It has been suggested that oocytes may develop from cells in the ovarian medulla. In order to test this hypothesis autografts of ovarian medulla were transplanted to various sites in fifty-five sexually mature rabbits. Tissue was recovered in only eighteen instances, but even these grafts were reduced in size. No oocytes were seen. In a further ten animals it was shown that grafts of cortical tissue persisted after medullary grafts had disappeared. It is concluded that medullary tissue cannot survive in the absence of the ovarian cortex. Five animals from which medullary tissue was recovered had uteri which were not as atrophic as the uteri of spayed controls. It is suggested that ovarian medullary tissue may secrete oestrogen, but that this capacity is soon lost in the absence of the follicular apparatus.