BIOLOGY OF SPERMATOZOA 



735 



in iiiucus collected after ovulation. No cy- 

 clical changes, however, were found by 

 Bergman and Werner (1950) in carbohy- 

 drate hydrolysates of cervical mucus, which, 

 when tested chromatographically, showed 

 the presence of galactose, mannose, fucose, 

 and hexosamine. 



A recent investigation of cervical mucus 

 from the cow (Gibbons, 1959a) has demon- 

 strated the presence of glucose, glycogen, 

 protein, alkaline phosphatase, lysozyme, an- 

 tagglutin, and common inorganic ions. Iso- 

 lation and relative purification of mucoid, 

 prepared from bovine mucin, show that it 

 changes in physical consistency with phases 

 of the cycle; molecular configuration, as de- 

 termined by sedimentation, viscosity, and 

 flow-birefringence measurements, is altered 

 and is probably due to changes in state of 

 liydration (Gibbons and Glover, 19591. 

 Chemically, bovine mucoid consists of about 

 75 per cent carbohydrate and 25 per cent 

 amino acid residues and resembles human 

 blood-group substances (Glover, 1959b). 



The presence of glucose and hydrolyzable 

 l)olysaccharide in cervical mucus suggests 

 the availability of metabolic substrate for 

 the spermatozoa, but the utilization of these 

 energy sources can only be conjectured. 

 Moricard, Gothie and Belaisch (1957) have 

 indicated that inorganic S^^ is apparently 

 taken up by human sperm from cervical 

 mucus, but the significance of this uptake 

 cannot at present be evaluated. 



Many investigators have attempted to 

 correlate cyclical changes in cervical mucus 

 with capacity for sperm progression, in vitro 

 (Fig. 13.9). Maximal penetration by human 

 sperm, observed in capillary tubes, occurs 

 in estrogenic cervical secretion when the 

 mucus is most copious and least viscous 

 (Lamar, Shettles and Delfs, 1940; Gutt- 

 macher and Shettles, 1940; Shettles, 1940; 

 Pommerenke, 1946; Leeb and Ploberger, 

 1959). Very little or no penetration is ob- 

 served in pre-ovulatory or postovulatory 

 mucus. Just before menstruation penetra- 

 l)ility sharply increases, a change probably 

 correlated with the premenstrual rise in 

 circulating estrogen. During pregnancy, cer- 

 vical mucus is only slightly penetrable, 

 although the endocervical glands are hyper- 

 active at this time (Guttmacher and Shet- 



tles, 1940; Atkinson, Shettles and Engle, 

 1948). Postmenopausal mucus is relatively 

 impenetrable by spermatozoa, but after ade- 

 quate estrogenic administration, a mucus is 

 secreted which is characteristic of that of the 

 ovulatory phase. Ovariectomized women or- 

 dinarily produce a scant, viscous mucus 

 which is increased upon estrogen administra- 

 tion (Moricard, 1936; Abarbanel, 1946, 1948; 

 Pommerenke and Viergiver, 1946). It has 

 been claimed (Gary, 1943), although not 

 confirmed, that mucous secretion in women 

 is enhanced by orgasm and that this facili- 

 tates sperm penetration. 



These studies on sperm, in vitro, have in a 

 general way largely confirmed the earlier 

 work of Sjovall ( 1938 ) , whose investigations 

 of sperm penetration through the guinea pig 

 cervix were mainly confined to observations 

 in vivo. The penetration of sperm through 

 the cervical mucus, in vitro, however, is at 

 best only an approximation to the normal 

 process of insemination and cervical trans- 

 port, and the meaning of these carefully 

 compiled results is not easy to assess. Their 

 full significance must await further correla- 

 tion between sperm migration in vitro and 

 transit in situ. Certain evidence, indeed, 

 tends to suggest that the condition of the 

 cervical mucus in women may be of rela- 

 tively little importance in sperm transport. 

 In the series of 51 women studied by Ruben- 

 stein, Strauss, Lazarus and Hankin (1951), 

 spermatozoa were found to have passed rap- 

 idly through the cervix at all stages of the 

 cycle. No particulars were given concerning 

 the condition of the cervical mucus, the pre- 

 surgical coital history of the patients, or the 

 possible effect of the operation (hysterec- 

 tomy) on sperm transport. Their re])ort, 

 however, seems to conflict with many of the 

 above-cited observations in vitro which in- 

 dicate that sperm migration is limited to the 

 ovulatory phase of the cycle. 



2. The Uterotubal Junction 



The speed of sperm transport through the 

 upper genital tract is in general so rapid 

 that in only two species, the rat and rabbit, 

 is the junction between the uterus and the 

 oviduct stressed in current literature as be- 

 ing an obstacle to sperm migration (Braden, 

 1953). Yet, for almost half a century, de- 



