ACCESSORY MAMMALIAN REPRODUCTIVE GLANDS 



395 



tate tissues. Awapara (1952a. bl reported 

 that the ahmine (but not aspartic) trans- 

 aminase activities of the ventral prostate 

 gland of the rat were decreased by castra- 

 tion, and increased by testosterone therapy. 



Rudolph and Starnes (1954) studied the 

 water distribution in the rat accessory 

 glands. The extracellular water in normal 

 seminal vesicles and prostates was 13.8 per 

 cent and 8.5 per cent, respectively. The 

 corresj^onding values in castrate animals 

 were 37.0 per cent and 31.8 per cent. The 

 growth of the glands which resulted from 

 treatment with testosterone was accom- 

 panied by a greater increase in the intra- 

 cellular water than in extracellular water. 

 Rudolph and Samuels (1949) provided evi- 

 dence that changes in the water content of 

 seminal vesicles induced by treatment of 

 castrate rats with testosterone did not \)re- 

 cede metabolic changes (e.g., fructose syn- 

 thesis) in this tissue. 



The pronounced effects of androgen ad- 

 ministration in vivo on the metabolism and 

 enzymatic activity of the accessary glands 

 cannot be mimicked by the addition of an- 

 drogens in vitro. Dirscherl, Breuer and 

 Scheller (1955) reported that low levels of 

 testosterone stimulated the respiration of 

 mouse seminal vesicles if the control respi- 

 ration was low. But others have found that 

 the respiration and glycolysis of male ac- 

 cessory glands are uninfluenced by the di- 

 rect addition of androgens /// I'itro except 

 at high concentrations (>5 X 10~^ m), at 

 which testosterone is inhibitory (Bern, 

 1953; McDonald and Latta, 1954, 1956; An- 

 drewes and Taylor, 19551. According to 

 Farnsworth (1958), the direct addition of 

 testosterone to prostate tissue impedes cit- 

 rate synthesis to a greater extent than oxy- 

 gen consumption. Williams-Ashman (1954) 

 found that the in vitro addition of testos- 

 terone did not affect the activity of a num- 

 ber of respiratory and glycolytic enzymes 

 in the rat A-entral prostate gland. 



The mechanism of action of androgenic 

 hormones at a molecular level is not known. 

 There is no evidence that androgens are di- 

 rectly involved in the large changes in the 

 activity of some enzyme systems in acces- 

 sory glands which follow the administration 

 or deprivation of these hormones. Recent 

 studies wliich indicate that minute concen- 



trations of certain steroid hormones can 

 stimulate the transfer of hydrogen between 

 pyridine nucleotides by isolated enzyme 

 systems deserve further comment. A soluble 

 enzyme in human placenta catalyzes an 

 estradiol- 17y8-dependent exchange of hy- 

 drogen between TPNH and DPN (Talalay 

 and Williams-Ashman, 1958). There is evi- 

 dence in favor of the hypothesis (Talalay, 

 Hurlock and Williams-Ashman, 1958; Tala- 

 lay and Williams-Ashman, 1960) that es- 

 tradiol- 17^ transports hydrogen in this re- 

 action by undergoing reversible oxidation 

 to estrone: 



Estrone + TPNH + H+ ^ Estradiol-17/3 + TPN 

 EstradioI-17/3 + DPN ^ 



Estrone + DPNH + H+ 

 TPNH + DPN ^ TPN + DPNH 



Hagerman and Villee (1959), however, 

 believe that estradiol- 17/;^ and estrone me- 

 diate transhydrogenation between TPXH 

 and DPN by a mechanism which does not 

 involve oxido-reduction of the steroids. 

 Hurlock and Talalay (1958) showed that 

 a soluble 3a-hydroxysteroid dehydrogenase 

 isolated from rat liver catalyzes hydrogen 

 transfer between pyridine nucleotides in the 

 presence of catalytic levels of androsterone 

 and some other 3a-hydroxysteroids. In this 

 instance also, it seems that the steroids act 

 in a coenzyme-like manner by undergoing 

 alternate oxidation and reduction. However, 

 biologically inactive steroids such as etio- 

 cholan-3a-ol-17-one are even more active 

 than androgenic substances such as an- 

 ch'osterone in this isolated enzyme system. 

 Hurlock and Talalay (1959) reported that 

 the particle-bound 3a- and 11^-hydroxy- 

 steroid dehydrogenases of rat liver react at 

 comparable rates with both TPX and DPN, 

 and they suggest that these dehydrogenases 

 might function as transhydrogenases in the 

 presence of their appropriate steroid sub- 

 strates. The hydroxy steroid dehydrogenases 

 for which there is direct or circumstantial 

 evidence for their ability to function as 

 transhydrogenases are localized either in 

 the microsomes (endoplasmic reticulum) or 

 in the soluble cell sap. Other enzymes that 

 catalyze the transfer of hydrogen between 

 pyridine nucleotides are bound to the mito- 

 chondria of many animal tissues (Stein, 



