STUDIES ON POSTNATAL-GROWTH OF RAT ADRENAL-CORTEX

  • 1 January 1977
    • journal article
    • research article
    • Vol. 123  (FEB) , 147-156
Abstract
In the male rat the volumes of the several zones of the adrenal cortex were measured using a point-counting technique at various ages. The resulting growth curves were fitted by the Gompertz method, and the specific growth rate calculated for each zone at 14 days of age. At 14 days the flash labeling index was measured in contiguous bands each 3 cells in thickness across the cortex; maximum indices were found in the outer cortical layers. Calculations of the birth rate for each zone were compared with the growth rates. In the zone glomerulsa, the birth rate exceeded the growth rate, giving a cell migration rate of 4 cells/1000 cells per h. In the zona reticularis there was a net cell gain of 5 cells/1000 cells per h; in this zone, for every 100 cells born by cell division, nearly 2000 were added by cell migration. The results support the migration hypothesis of adrenocortical cytogenesis.