ACCESSORY MAMMALIAN REPRODUCTIVE GLANDS 



379 



two years. Normal adult dogs were found 

 to secrete 0.1 to 0.2 ml. of prostatic fluid per 

 hour without external stimulation. Follow- 

 ing the administration of pilocarpine, the 

 canine prostate secreted as much as four 

 times its weight of fluid (60 ml.) in one 

 hour. The amount of secretion obtained in 

 response to a standard dose of pilocar- 

 pine remained relatively constant for three 

 months or more, and bore no direct relation- 

 ship to the weight of the gland. The volume 

 and composition of the fluid varied with the 

 time and intensity of the cholinergic stimu- 

 lus. Huggins (1947c) found that, after a 

 single intravenous injection of pilocarpine, 

 the volume and the content of total pro- 

 tein, certain enzymes (acid phosphatase, fS- 

 glucuronidase and fibrinogenase ) , and cit- 

 rate were maximal in the first 15 minutes, 

 then declined progressively in three succeed- 

 ing quarter-hour periods. But the chloride 

 content always rose initially from the low 

 values of the resting secretion and reached 

 maximal levels after the first 15-minute 

 period. If the drug was administered intra- 

 muscularly, maximal values for total pro- 

 tein and citrate were found in the first pe- 

 riod, whereas those for the volume and 

 enzyme content were higher in the second 

 and third periods. It was concluded from 

 experiments involving the repeated intra- 

 venous injection of pilocarpine that acid 

 phosphatase and fibrinogenase were defi- 

 nitely secreted and not simply washed out 

 of the gland. However, a "washing out" 

 process does occur after an initial stimulus 

 with respect to total protein and citrate 

 levels. 



It was observed by Huggins, Masina, 

 Eichelberger and Wharton (1939) that in- 

 fectious diseases {e.g., pyelonephritis, dis- 

 temper) often decreased the volume of 

 stimulated fluid. This effect seemed to be 

 due to inhibition of the hypophysis, because 

 it could be overcome by injection of gonado- 

 trophin. Soon after castration (7 to 23 days) 

 the secretion ceased and was restored by the 

 administration of testosterone propionate. 

 Androgens also initiated secretion in imma- 

 ture animals. In castrate dogs maintained on 

 testosterone, neither adrenalectomy nor re- 

 moval of the thyroid and parathyroid glands 

 affected the rate of prostatic secretion. 

 Huggins (1947c) observed that in normal 



Fig. 6.5. The canine prostatic isolation operation. 

 The connection of the prostatic urethra with the 

 bhulder has been severed and the prostatic secre- 

 tion is collected by way of the penis. (From C. 

 Huggins and J. L. Sommer, J. Exper. Med., 97, 663- 

 680, 1953.) 



animals, secretion was unaffected by in- 

 jection of either progesterone or desoxy- 

 corticosterone. 



Cystic hyperplasia of the prostate occurs 

 in many senile dogs. The volume of fluid 

 secreted by such hypertrophied glands in 

 response to pilocarpine was smaller than 

 that obtained from young adult animals 

 (Huggins and Clark, 1940). 



Injection of diethylstilbestrol into normal 

 adult dogs abolishes prostatic secretion. Ad- 

 ministration of gonadotrophin restores se- 

 cretion in such estrogen treated animals, 

 which suggests that the primary effect of 

 estrogens under these conditions is on the 

 hypophysis (Huggins, 1947c). Estrogens 

 also antagonize the stimulatory effects of 

 injected androgens. In castrate dogs re- 

 ceiving testosterone, injection of large doses 

 of diethylstilbestrol decreases the output of 

 prostatic fluid to very low levels (Huggins 



