380 



PHYSIOLOGY OF GONADS 



and Clark, 1940). The neutralization of 

 androgen action by estrogens in this situa- 

 tion is pronounced but not complete. Thus 

 the acid phosphatase activity of prostatic 

 fluid collected from animals treated with 

 both testosterone propionate and diethyl- 

 stilbestrol is of the same order of magnitude 

 as that of normal secretion, despite the fact 

 that the volume of the secretion is ex- 

 tremely low (Huggins, 1947c). The ratio 

 of diethylstilbestrol recjuired to antagonize 

 maximally the action of testosterone was 

 found to be about 1 : 25. In dogs with either 

 normal or cystic prostate glands, injection 

 of amounts of estrogen sufficient to decrease 

 prostatic secretion leads to shrinkage of the 

 prostate. Large doses of estrogen cause the 

 canine prostate gland to enlarge ; the dorsal 

 segment undergoes squamous metaplasia 

 and the ventral lobe becomes atrophic 

 (Huggins and Clark, 1940; Huggins, 1947c). 

 If both estrogen and androgen are adminis- 

 tered simultaneously, the dorsal region be- 

 comes squamous and the ventral portion of 

 the gland retains its columnar epithelium, 

 although the volume of the prostatic secre- 

 tion may be drastically reduced. 



Fig. 6.6. The c-anine prostatic translocation op- 

 eration. (From C. Huggins and J. L. Sommer, J. 

 Exper. Med., 97, 663-680, 1953.) 



2. Prostatic Translocation Operation 



Huggins and Sommer (1953) transposed 

 the prostate gland of the dog from its natu- 

 ral position to the perineum, as depicted in 

 Figure 6.6. This procedure permitted the 

 size of the prostate to be measured in the 

 living animal, and provided prostatic fluid 

 quite uncontaminated with other material. 

 Pilocarpine was used as a secretory stimu- 

 lus. Using this technique, Huggins and Som- 

 mer found that the effects of androgens and 

 estrogens on prostatic size and secretion 

 were similar to those obtained with dogs 

 that had undergone the prostatic isolation 

 operation. 



C. CHEMICAL COMPOSITION OF THE 

 GLANDULAR SECRETIONS 



Electrolytes. Water is the main constit- 

 uent of prostatic and seminal vesicle secre- 

 tions and of seminal plasma, all of which 

 are approximately iso-osmotic with respect 

 to blood serum. The vesicular secretion is 

 usually more alkaline than the prostatic se- 

 cretion and has a higher dry weight, mainly 

 because it contains more protein. The elec- 

 trolyte content of the secretions varies 

 widely between different species (Huggins, 

 1945; Mann, 1954a). In general, sodium is 

 the main cation, although this is not true of 

 boar vesicular secretion which is very rich 

 in potassium. Chloride tends to be the main 

 anion in those species whose accessory gland 

 secretions do not contain large amounts of 

 citrate. In this connection it is instructive 

 to compare the resting prostatic fluid of 

 man, and the pilocarpine-stimulated pros- 

 tatic fluid of the dog (Huggins, 1945, 1947c). 

 The human secretion has a much greater 

 citrate and calcium content, and a much 

 smaller chloride level than the correspond- 

 ing canine fluid, although the total concen- 

 tration of osmotically active substances is of 

 the same order of magnitude in both secre- 

 tions. 



Zinc. Berti'aiid and X'hidesco (1921 » found 

 large amounts of zinc in human semen. The 

 highest concentration of zinc is present in 

 the first fraction of the ejaculate, which is 

 largely prostatic secretion (Mawson and 

 Fischer, 1953). In the rat, the zinc content 

 of the dorsolateral prostate is especially 

 lii<i;li (.Mawson and Fisclicr, 1951 ). After in- 



