The biochemical growth and development of the palate, maxilla, mandible and tongue in the New Zealand white rabbit

Seventy-two female New Zealand white rabbits were divided into six groups and killed with Nembutal at 17.0, 17.5, 18.0, 18.5, 19.0 and 19.5 days postconception. The foetuses were removed; the palates, maxilla, mandibles and tongues were dissected from each foetus, weighed and pooled; DNA, RNA and protein were determined in each pooled sample. The results showed three distinct patterns of development. The mandible and maxilla showed similar developmental patterns, while the palate and tongue each showed their own distinct pattern. The palate showed a remarkable rise in protein/DNA at day 18.0, the time corresponding to palatal closure in our rabbits. Further such studies may elucidate the role that relative growth rates of these tissues plays in the aetiology of cleft palate.