ACCESSORY MAMMALIAN REPRODUCTIVE GLANDS 



375 



with only the most medioventral part of the 

 male prostate ; the lobes are bilateral or uni- 

 lateral, with the right the preferred side; 

 each lobe has a single duct which opens into 

 the urethra. The incidence of female pros- 

 tates varies markedly in different strains, 

 and can be increased by selective inbreed- 

 ing, w^iich also increases the occurrence of 

 bilateral compared with unilateral lobes. 

 The frequency of female prostates was in- 

 creased in the Wistar stock from 28 to 99 

 per cent, but when selective inbreeding was 

 stopped, the frequency declined. 



In young untreated female rats, the pros- 

 tate, when present, develops a histologic 

 structure identical with that of the male 

 homologue, but at about 6 weeks of age the 

 epithelium undergoes regression (Price, 

 1939; Mahoney, 1940) and becomes histo- 

 logically well developed again only during 

 pregnancy and lactation (Burrill and 

 Greene, 1942; Price, 1942). Thus, the fe- 

 male prostate of the rat is not only homolo- 

 gous with a part of the ventral prostate of 

 the male on the basis of embryologic devel- 

 opment, but during early postnatal devel- 

 opment and in periods of pregnancy and 

 lactation it resembles its male homologue 

 histologically (Fig. 6.46). In addition, it is 

 functionally equivalent (see Section II) to 

 the male ventral prostate in the secretion 

 of citric acid (Price, Mann and Lutwak- 

 Mann, 1949). 



Brambell and Davis (1940) found large, 

 well developed prostate glands in every one 

 of 104 female African mice, Mastonujs 

 erythroleucus Temm. These glands consist 

 of paired lobes, each draining into the 

 urethra by a single duct. They resemble the 

 ventral prostate of the male in position, 

 shape, and histologic structure. On the ba- 

 sis of this evidence it was concluded that 

 the female glands are the homologues of the 

 male ventral prostate. In some cases, the 

 female prostates are nearly as large as their 

 male homologues and are actively secre- 

 tory. Brambell and Davis correlated hyper- 

 trophy and secretory activity with the lu- 

 teal phase of the cycle and gestation. 



Female prostate glands have also been de- 

 scribed in the field mouse, Apodemns syl- 

 vaenms sylvaticus. Raynaud (1942, 1945) 

 found bilobed prostates in 51 immature and 



adult females collected in the vicinity of 

 Vabre (Tarn) and in 3 females from three 

 other regions of France. However, the lobes 

 were macroscopically visible in only 10 fe- 

 males; in all others, the glands were identi- 

 fied in histologic preparations. There w^as 

 great variability in histologic structure, but 

 a well developed epithelium showing secre- 

 tory activity was found during pregnancy 

 and lactation. Raynaud established that the 

 female prostate is homologous with a part 

 of the male ventral prostate. He concluded 

 that there is a probability that bilobed fe- 

 male prostates exist normally in all females 

 of Apodemus sylvaticus. 



The prostate glands in adult female field 

 voles, Microtiis arvalis P., are considered 

 homologous with the ventral lobes and part 

 of the lateral lobes of the male prostate 

 (Delost, 1953a, b). The lobes in the female 

 are lateral in position in part of the gland, 

 but in other regions they completely sur- 

 round the urethra. The structure is identical 

 with that of the ventral prostate of the male. 

 The epithelium appears secretory in normal 

 adult females, and during gestation this ac- 

 tivity is intense. 



Bilobed female prostates were found in 

 the 37 adult cottontail rabbits examined by 

 Elschlepp (1952). They lie on the dorsal 

 wall of the vagina (Fig. 6.4) and are simi- 

 lar histologically to the prostate of the male. 

 The glands are larger in pregnant than in 

 nonpregnant females and contain more se- 

 cretion. 



In summary, well developed female pros- 

 tate glands are present in immature and 

 adult females of many species. They may 

 occur as ventral, lateral, or dorsal lobes; the 

 lobes may be unilateral or consistently bi- 

 lateral; their occurrence may be sporadic 

 or reach an incidence of 100 per cent; they 

 are found both in laboratory strains and in 

 wild populations. The genetic studies of 

 Witschi and his collaborators show that the 

 incidence in rodents can be increased by 

 selective inbreeding. In certain populations 

 of wild rodents the character has become 

 established. A striking example of this is the 

 presence of large prostates in all female 

 Masto)7iys erythroleucus. The secretory ac- 

 tivity of the glands seems to be controlled 

 mainly by ovarian androgens (sec Section 



