Effect of hypophysectomy on the volume and ultrastructure of zona glomerulosa in rat adrenal

The zona glomerulosa was examined at various times after hypophysectomy. There was no detectable change 2 days after hypophysectomy. However by 7 days, the width of the zona glomerulosa became significantly larger in spite of an absolute decrease in its volume. No alterations in ultrastructure were discernible at this time, although giant mitochondria were seen in the adjacent zona fasciculata cells. By 30 days there was a much wider zona glomerulosa and a restoration of its volume to that found in controls. Many glomerulosa cells were hypertrophic. The Golgi apparatus was enlarged and many vesicles were associated with peripheral cisternae. After 30 days a few intramitochondrial tubules were observed.