378 



PHYSIOLOGY OF GONADS 



has not been achieved for purely technical 

 reasons. The use of "split ejaculates" has 

 given some insight into the glandular origin 

 of various conii)oncnts of the seminal 

 plasma, but this techniciue does not provide 

 uncontaminated secretions from any one 

 gland. However, in the last two decades ex- 

 tensive analyses of the chemical and enzy- 

 matic constituents of the individual secre- 

 tions stored in the accessory glands, and of 

 the whole seminal plasma, have been per- 

 formed. The levels of many of these sub- 

 stances and enzymes are dependent on an- 

 drogenic hormones. These findings have 

 provided a basis for sensitive chemical 

 methods for the bioassay of androgens. 

 Moreover, knowledge of the biosynthesis of 

 these substances by the accessory glands 

 may point to the primary biochemical locus 

 of action of androgenic steroids. This chemi- 

 cal approach to the study of the accessory 

 glands has received great impetus from the 

 pioneer studies of Thaddeus Mann. 



The secretions of the accessory glands of 

 many species are a repository for huge 

 Cjuantities of substances which are present 

 only in trace amounts in other tissues and 

 body fluids. It is obvious that the seminal 

 plasma must provide an ionically balanced 

 and nutritive milieu suitable for the sur- 

 vival of sperm in the vagina and uterus. 

 Certain substances secreted by one or more 

 of the accessory glands, e.g., fructose, un- 

 doubtedly serve as a source of energy for 

 the sperm. However, there is no evidence 

 that any component of mammalian seminal 

 plasma, or any one of the accessory glands, 

 is absolutely indispensable for fertility. Ar- 

 tificial insemination is successful in some 

 mammals if sperm from the epididymis are 

 diluted in a suital)ly prepared medium, 

 placed in a female in the correct stage of the 

 estrous cycle, and deposited in a region of 

 th(; female tract where there is maximal 

 opiiortunity for their successful ascent. Re- 

 moval of the coagulating glands in guinea 

 l)igs (Engle, 1926b) , or dorsolateral prostate 

 (Gunn and Gould, 1958) in rats does not 

 prevent insemination and fertilization. Blan- 

 dau (1945) extirpated the seminal vesicles 

 and coagulating glands of rats and found 

 that when these males were mated there was 

 no copulation plug and, evidently as a re- 

 sult, the spermatozoa did not penetrate the 



vaginal canals of the females. Thus the se- 

 cretions of the coagulating gland and semi- 

 nal vesicles in the rat assist the transport 

 of sperm in the female. 



The following section will consider the 

 output and composition of the secretions, 

 and their hormonal regulation, primarily 

 from a chemical standpoint, rather than in 

 relation to the anatomy and embryology of 

 the structures from which they originate. 



B. VOLUMETRIC (STUDIES OF SECRETION 



1. Prostatic Isolation Operation 



Volumetric studies of the secretion of 

 canine prostatic fluid have yielded great in- 

 sight into the factors which determine the 

 functional activity of male accessory glands. 

 The dog is devoid of both seminal vesicles 

 and bulbo-urethral glands, and if the urine 

 is suitably deviated, practically pure pros- 

 tatic secretion can be collected from the 

 urethra. Eckhard (1863) ligated the neck 

 of the bladder of dogs and obtained pros- 

 tatic fluid by urethral catheterization. This 

 technique was used by a number of investi- 

 gators to study the secretory activity of the 

 i:)rostate gland (Mislawsky and Bormann, 

 1899; Sergijewsky and Bachromejew, 1932; 

 Winkler, 19311. A superior modification of 

 the operation was introduced by Farrell 

 (1931, 1938; Farrell and Lyman, 1937). The 

 output of prostatic fluid was increased 

 greatly either by electrical stimulation of 

 the nervus erigens or by the injection of 

 cholinergic drugs such as pilocarpine. These 

 early prostatic isolation operations suffered 

 from the signal disadvantage that, for 

 technical reasons, they permitted only brief 

 experiments. 



In 1939, Huggins, Masina, Eichelberger 

 and Wharton developed a simple surgical 

 procedure which enabled frequent collection 

 of canine prostatic secretion over long 

 l)eriods of time. The original technique was 

 modified slightly by Huggins and Sommer 

 (1953) and is depicted in Figure 6.5. The 

 bladdei' is separated from the prostate 

 gland, the urine voided through a supra- 

 l)ubic canula, and the animals circumcised. 

 Healing was complete within one week after 

 surgery, and the animals were maintained in 

 good health. Prostatic fluid could be col- 

 lected at fre(iucnt intervals for as long as 



