POSTNATAL MORPHOGENESIS OF SHEEP THYROID GLANDS RAISED IN DIFFERENT NATURAL AREAS.

Abstract

The present results, considered with results of other investigations of the effects of thyroid hormone deficiency in fetal and newborn mammals, indicate that hypothyroidism impairs somatic growth, delays bone growth and maturation, delays cell growth and replication in the CNS, and inhibits CNS myelination. The critical period for these effects varies in different species. In the rat this period is postnatal, whereas in the sheep it extends into the third trimester of pregnancy.