Direct effects of oestradiol on growth and morphology of the Dunning R3327H prostatic carcinoma.

Male Copenhagen x Fischer F1 rats were implanted with Dunning R3327H prostatic carcinoma, castrated when the tumours became palpable and were then treated with testosterone, testosterone in combination with oestradiol or oestradiol alone for four weeks. Treatment with oestradiol produced the smallest tumours. The testosterone-stimulated growth of tumours was inhibited by oestradiol. The adenocarcinoma was moderately to well-differentiated. Morphometric analysis of the composition of the tumours showed that oestradiol stimulated tumour stroma and inhibited glandular epithelium. These effects were produced concomitantly with decreased overall tumour growth. Testosterone stimulated all cell types of the tumour.