THE EFFECT OF PERINATAL DEXAMETHASONE ON THE PITUITARY CORTICOTROPHS AND FOLLICULOSTELLATE CELLS IN RATS: IMMUNOHISTOCHEMICAL AND ULTRASTRUCTURAL STUDY
Tarek A. El-Ghamrawy and Laila A. Rashed*
Anatomy and *Biochemistry departments, Faculty of Medicine, Cairo University
Glucocorticoids (GCs) were used in obstetric practice to advance the maturation of the foetal lungs in conditions of preterm birth. They had early and long-term effects on their delivered babies. The objective of this study was to disclose the late effect of perinatal administration of dexamethasone on the morphology of the offspring pituitary corticotrophs and folliculostellate (FS) cells. This was performed by using immunohistochemical and ultrastructural studies. Gene expression of Annexin-1, which is a mediator of FS cells, was also performed. Seventy offspring rats were used in this study. They were divided into three groups: control, prenatal and neonatal ones. Prenatal group included those offsprings whose mothers received dexamethasone in drinking water on days 16-19 of pregnancy. Neonatal group included those whose mothers received dexamethasone in the first week after delivery during lactation. After weaning they were isolated till adulthood and their pituitary glands were studied. Both prenatal and neonatal dexamethasone treatment produced long-term changes in the offsprings. In the prenatal group, the corticotrophs showed a decrease in ACTH immunoexpression and secretory granules in the cell. Also the number of cells was reduced. In the neonatal group the corticotroph number increased and the secretory activity of the cells was regained. The FS cell S100 protein decreased in the two treated groups. There was a significant reduction in prenatal and neonatal level of Annexin-1 gene expression but more in the prenatal group. Further studies including gender differences within the offsprings and on other pituitary trophic cells to show the changes in response to the stress induced by GCs are recommended in the future.