Effect of melatonin-free pineal extract on acid phosphatase activity in the testosterone-treated, castrated rat

The effect of a melatonin-free pineal extract on acid phosphatase activity in the prostate of castrated and testosterone-treated rat was studied. Prostatic acid phosphatases in the mature rat are lysosomal and secretory, the former being inhibited by tartrate. Castration induces a decrease in the secretory phosphatases and an increase in the lysosomal ones with a subsequent increase in the tartrate-induced inhibition index. The specific activity of total acid phosphatase also rises. Administration of the pineal extract in the first 4 post-surgical days did not have a significant effect, but when it was prolonged to 7 days, it partially inhibited the effect of castration on prostatic acid phosphatase. Administration of testosterone to the castrated rat in the first 4 post-castration days, partially compensated the prostatic alterations, owing to the fact that the prostate is under the control of androgenic hormones. Administration of both pineal extract and testosterone in the first 4 post-castration days partially inhibited the effect of testosterone. The equillibrating role of the melatonin-free pineal extract and its effect in relation to the amount of time lapsed from surgery is discussed.