Endocrine Cytodifferentiation of the Rat Fetal Testis

Growth of the fetus involves not only increase in the number of cells or in weight of the body, it is actually accompanied with functional differentiation of new cell types at definite developmental periods. This is especially obvious when endocrine glands are considered. These glands undergo first a local embryogenesis, before the day they enter physiologically into play and release appreciable amounts of hormones. Their cells acquire then characteristics of endocrine activity. The mechanisms responsible for the initial differentiation and sudden functional activation are still unknown. Endocrine and Biochemical Development of the Fetus and Neonate