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The morphological effects of dexamethasone on the pituitary–adrenal axis of the rat—a quantitative study
Author(s) -
McNicol Anne M.,
Kubba M. A.,
Stewart C. J. R.
Publication year - 1988
Publication title -
the journal of pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.964
H-Index - 184
eISSN - 1096-9896
pISSN - 0022-3417
DOI - 10.1002/path.1711540211
Subject(s) - dexamethasone , endocrinology , medicine , pituitary gland , hormone
Abstract Adult Sprague–Dawley rats received a daily intraperitoneal injection of dexamethasone (100 or 200 μg/kg) for 2 or 6 weeks. Quantitative assessment of the anterior pituitary corticotroph population was performed using the stereological measurement of volume density ( V v ). An indirect assessment of corticotroph function was also made, based on adrenal weight and histology. Adrenal changes were consistent with dose‐related inhibition of corticotroph function in all dexamethasone‐treated animals. Immunopositive corticotrophs were easily identified and in no treatment group was corticotroph V v significantly less than in the appropriate vehicle‐injected control group. In male animals, there was a significant increase ( P <0·05) in V v with 100 μg/kg at both 2 and 6 weeks. These results suggest that it is possible to produce inhibition of corticotroph function by the administration of such doses of dexamethasone without causing a significant reduction in the anterior pituitary corticotroph population. This may be related to the mode of negative feedback of such a regime.