Prostatic weights, 5alpha-reductase, and arginase activities were utilized as indexes for the effects of prolactin in short-term experiments in intact, hypophysectomized or castrated rats. Experiments were performed in which a dose-related response in the above parameters was obtained with testosterone administration in castrated mature and immature rats in order to evaluate the effects of simultaneously administered prolactin. This approach was necessitated by the failure of prolactin alone to affect the parameters listed in intact, castrated or hypophysectomized rats. It was shown that ovine prolactin may have an enhancing effect on the prostatic weight, 5alpha-reductase, and arginase activities, but that this effect is neither consistent nor striking when compared to that of testosterone.. Nevertheless, it is still possible that the long-term effects of prolactin, even if they are only of an enhancing quality, may play an important role in normal prostatic physiology and in abnormal states.

Testosterone (T), dihydrotestosterone (DHT) and prolactin (HPr) levels were determined in normal males and females, in patients with benign prostatic hypertrophy (BPH) and in clinically stable patients with prostatic carcinoma (CAP), intact and orchiectomized. CAP patients were either untreated or on different modalities of therapy. The HPr levels were higher in prostatic cancer patients, in BPH patients, and in subjects on estrogen therapy. No significant differences were found between controls or patients treated with 5-Fu plus Cytoxan. The T and DHT levels were decreased in all noncontrol subjects. The levels of DHT in intact, untreated CAP patients or those receiving 5-FU plus Cytoxan were significantly higher than in BPH patients. Based on these observations, it appears that HPr could be involved with T and DHT in a feedback control role, especially in BPH. The alterations in these hormone levels in CAP treated or untreated patients are in marked contrast and must be evaluated further.

The alkaline phosphatase isoenzymes in 105 patients with stage D carcinoma of the prostate who entered the National Prostatic Cancer Study were analyzed and these values were correlated to clinical response. Only patients with at least 3 measurements of alkaline phosphatase were evaluated. In 91% of patients with metastatic bone disease, bone alkaline phosphatase was elevated. Those patients with higher pre-treatment levels of alkaline phosphatase generally showed a poorer response to therapy. The results of alkaline phosphatase isoenzyme estimation indicate that these biological markers may be used in the evaluation of patients with metastatic prostatic cancer to predict and monitor their response to chemotherapy. The evaluation of bone and liver alkaline phosphatase isoenzymes in earlier stages also may be valuable.

The response and duration of survival were evaluated for patients with stage D relapsing prostatic cancer who were randomized to cyclophosphamide (cytoxan), 5-fluorouracil (5-FU) or standard therapy, or to subsequent chemotherapies. The chemotherapies on initial randomization were superior to the standard therapy in the number of responders and duration of response. Survival was longer for responders (stable or partial regression) on chemotherapy by comparison to responders (stable only) on standard therapy. The survival for patients receiving initial and crossover chemotherapy was significantly improved for patients who responded to therapy. Chemotherapy of advanced relapsing stage D prostatic cancer is more beneficially treated by specific chemotherapy as shown in this randomized study.