Some histological observations on postnatal growth of rat adrenal gland with advancing age (a HRLM study)
2004
Mughal, I.A. (Independent Medical Coll., Faisalabad (Pakistan)) | Qureshi, A.S. | Tahir, M.S.
The present work elucidates postnatal cytological changes in the adrenal gland with regard to their cortical zones, cell count, nuclear size and lipid contents with advancing age. Thirty six litter mates of 9, 11, 13, 15, 17 and 19 days of age (postnatal) were used by dividing into six groups. Adrenals were dissected free, fixed in glutaraldehyde, post fixed in osmic acid and then stained with 1 % toluidine blue solution to study under the light microscope. The adrenal gland which is surrounded by a well developed fibrous capsule, showed a decrease in connective tissue fibers with a steady increase in capsular cells from day 9 to 19. The capsule showed a decrease in the mitotic activity with advancing, age. The cortical tissue showed three cortical zones, i.e., zona glomerulosa, zona fasciculata and zona reticularis. The zona lomerulosa was well developed. The radial columns in zona fasciculata and zona reticularis became more distinct on 13th day onwards. The medullary cells in groups were found to invade from capsular region to the zona glomerulosa and then to zona fasciculata. Predominance of dark cells over the light cells was observed in all groups. There was an overall little increase in size of the inner zones, which might be attributed to the disappearance of many of the medullary cells. The intracellular lipid content in the zona glomerulosa was significant. In the zona fasciculata, the lipid content was little with very meager amount in the juxtamedullary portion too. The medulla appeared distinctly on day 9 of postnatal life covering a larger area. There was predominance of dark cells over the light cells in the medulla throughout the study. It is concluded that functional zonation which characterizes the cortex of the adult rat extends back to neonatal period and that the cells in both the zona glomerulosa and fasciculata actively secret in the infant adrenal.
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