Subcellular localisation of VEGF in different pituitary cells. Changes of its expression in oestrogen induced prolactinomas |
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Authors: | Jorge Humberto Mukdsi Ana Lucía De Paul Silvina Gutiérrez Félix Daniel Roth Agustín Aoki Alicia Inés Torres |
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Institution: | (1) Centro de Microscopía Electrónica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, C.P. 362, X5000 HRA Córdoba, Argentina |
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Abstract: | Summary Vascular endothelial growth factor (VEGF) is an important angiogenic factor in the pituitary gland. The objective of this
study was to unveil the VEGF subcellular localisation in different pituitary cell types and to evaluate changes in its expression
at different time intervals after oestrogen stimulation. A relevant feature demonstrated was the identification of this cytokine
in the nucleus and cytoplasm of lactotrophs, somatotrophs and gonadotrophs, as well as in follicle-stellate cells of male
rats. Oestrogen treatment increased the number of VEGF immunopositive cells and its expression detected differentially by
western blot in both nucleus and cytoplasm of pituitary cells when compared to the control. At ultrastructural level VEGF
appeared associated with nucleolus and euchromatin involving a possible internal autocrine loop. In lactotrophs, the predominant
cell of the tumour, VEGF was immunodetected in RER, Golgi complex, and vesicular organelles, supporting further the association
with an auto-paracrine effect exerted by VEGF. The nucleus/cytoplasm ratio of VEGF revealed a prevalent accumulation of VEGF
in the cytoplasm. The presence of VEGF in the nucleus may probably be associated with a translocation to this cell compartment.
This study demonstrated a cytoplasmic and nuclear immunolocalisation of VEGF in normal and tumoural adenohypophyseal cells.
In the course of prolactinoma development, the oestrogen stimulated VEGF expression in tumoural cells, promoting a vascular
adaptation which contributes to growth and progression of the tumour. |
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Keywords: | VEGF oestrogen prolactinoma ultrastructure immunocytochemistry |
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