Catch-up growth in the rat skull after retardation during the suckling period.

In rats whose growth was restricted by rearing in large litters the skull was less affected than the spine and the brain case less than the face. No sex difference was apparent during undernutrition but on subsequent rehabilitation females had caught up to controls in four out of five skull measurements within 4 weeks and by the end of the experiment the skulls of the neonatally undernourished females were the same size and shape as the controls. In the case of males, however, the skull of the undernourished rats never attained the same width as the controls.