Cortisone-Induced Congenital Cleft Palate in Rabbits¹

WHEN pregnant mice were treated with large doses of cortisone they frequently resorbed their litters (Fainstat, 1951a). Subresorptive doses of cortisone were given and a variety of congenital defects was present among the newborn. Cleft palate was the most frequently visible gross defect. Greatly reduced birth-weights and a very high incidence of stillbirths were evident. The response to cortisone treatment, as measured by the incidence of cleft palate, was markedly influenced by the genetic makeup of the animals, since well-defined differences between mice of different strains were observed in response to identical cortisone treatment (Fraser and Fainstat, 1951; Fainstat, 1953; Fraser, Fainstat and Kalter, 1953). To learn whether the above phenomena occur only in the mouse, or whether they could apply to other mammals, the following parallel experiments were performed with rabbits. materials and methods Cortisone acetate3 was injected intramuscularly into the quadriceps in daily doses of 25 and 30 mg. for 4 consecutive days.