Quarterly Journal of Microscopical Science, Vol s2-78, 329-366, Copyright © 1935 by Company of Biologists

Memoirs: The Development of the Adrenal Gland of the Mouse

¹ University of Liverpool

1. The cortical anlage is constituted from the mesenchyme at about the 12th day of embryonic life.

2. The medullary anlage is constituted at about the 13th day of embryonic life from the anlage of the sympathetic nervous system and lies closely adpressed to the cortical anlage.

3. At about the 14th day sympatho-chromaffin elements migrate from the closely adpressed sympathetic nervous mass into the cortical anlage and form irregularly arranged ‘nests’ in its substance.

4. Between 16 and 18 days of foetal life part of the cortical substance has differentiated by becoming less eosinophil and is destined to form the adult permanent cortex.

5. By the day of birth the sympatho-chronianin elements are concentrated at the centre of the gland and are beginning to metamorphose into medullary cells.

The undifferentiated eosinophil cortical tissue now forms a layer immediately outside the medulla and interlocking with the medullary tissue.

The less eosinophil tissue now shows the first distinct signs of the arrangement characteristic of the adult glomerular and fasciculate zones.

6. After birth, in both sexes, the interlocking zone increases, attaining its maximum at about 21 days in the male but continuing to increase in the female, so that at about 25 days there is a distinct sex difference.

The three zones of the adult cortex are distinguishable in both sexes by 25 days the glomerulosa, zona fasciculata, and zona reticularis.

The reticular zone is distinctly a product of the zona fasciculata and not of the interlocking eosinophil zone.

7. At 80 days in the male degeneration of the interlocking zone has begun in the female the zone is still increasing. The male reticular zone is now very clearly developed but that of the female has remained at the 25-days condition.

8. At 35 days in the male degeneration of the interlocking zone has become well established. In the female this zone attains its maximum development at about this period.

9. By 56 days in the male the degeneration of the interlocking zone is complete, leaving a connective tissue capsule between the medulla and the well-marked zona reticularis of the permanent cortex. (The female is not discussed beyond 35 days.) 10. The interlocking zone of the adrenal of the mouse (X-zone of Miller) is shown to be probably homologous with the boundary zone of man and of the cat.