Prolactin, EGFR, vimentin and α-actin profiles in elderly rat prostate subjected to steroid hormonal imbalance

• The prolactin could be activated in an androgen and estrogen independent pathway.
• The changed EGFR immunolocalization in senile animals could contribute to proliferative process.
• The stromal reactivity could be considered as potentiator of the prostatic alterations.

The aim of this study was to characterize and relate the prolactin (PR), epidermal growth factor receptor (EGFR), α-actin and vimentin immunoreactivity in the prostate of elderly rats subjected to steroid hormonal imbalance. Senile and young rats were divided into the young group (YNG), the senile group (SE), the castrated group (CAS), the estrogen-deficient group (ED), the castrated + estrogen group (CASE), and the estrogen-deficient + androgen group (EDTEST). PR and EGFR increased in the estrogen and androgen ablation groups. In addition, EGFR influenced the immunolocalization by changing it from the prostatic stroma to the epithelium in elderly rats. Hormone ablation in elderly rats, not only related to androgen but also estrogen, led to increased stromal EGFR immunolocalization. The α-actin pattern decreased in the groups with estrogenic imbalance. Moreover, vimentin increased in the senile and estrogen deficient group. To conclude, we can suggest that EGFR contributed towards the proliferative process in the prostate, by means however, of different mechanisms, considering the androgenic and estrogenic pathways. Also, our results indicated that prolactin could be activated not only in an androgen-independent pathway but also in an estrogen independent pathway. Finally, PR and vimentin immunolocalization increase, in the prostatic stroma in the group showing estrogenic ablation, could be one of the factors which contribute to the reactive stroma formation.

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