Résumé : We have established organ cultures of human prostate in vitro analysis of the hormone responsiveness of prostatic carcinoma. The influence of dihydrotestosterone (DHT), the epidermal growth factor (EGF) and prolactin (PRL) was assessed on the proliferation rate of 30 benign human prostatic hyperplasias (BPH) maintained for 48 hours as short-term primary cultures. The influence exerted by the EGF, the DHT and the PRL on the BPH cell proliferation was characterized by adding these compounds alone or in combination to the culture media. The proliferation rate was assessed by means of histo-autoradiographical nuclear labeling with triated thymidine. The results show that of the DHT, EGF and PRL, the first two induced a statistically significant increase in the cell proliferation rate in a proportion of BPH significantly higher than the proportion of BPHs whose cell proliferation was increased significantly by the PRL. Furthermore, the PRL was able to antagonize the EGF-induced stimulatory effect on the BPH glandular cell proliferation rate. Lastly, the EGF- and PRL-mediated effects on the BPH glandular cell proliferation correlated with each other, while the DHT-mediated did not correlate with either the PRL- or the EGF-mediated effects. This model of organ, culture provide a basis for developing a method for in vitro testing of the individual hormone and drug responsiveness of a prostatic carcinoma.