BIOLOGY OF EGGS AND IMPLANTATION 



825 



the fimbriated end contained lipid droplets. 

 It is interesting as noted earlier that in the 

 rat no histochemical changes could be dem- 

 onstrated during the various phases of the 

 estrous cycle. In the sheep an acid muco- 

 polysaccharide is secreted by the oviduct 

 most profusely at the time of ovulation 

 (Hadek, 1955). Amylase is present in the 

 .secretions of the oviducts of man, cow, rab- 

 bit, and sheep in concentrations above that 

 found in homologous sera. The significance 

 of the relatively high concentrations of this 

 enzyme in relation to the reproductive proc- 

 ess is not clear (McGeachin, Hargan, Potter 

 and Daus, 1958). 



In man glycogen occurs not only in the 

 ciliated cells but also in the nonciliated epi- 

 thelia. Even though it is impossible to draw 

 a firm conclusion regarding the correlation 

 of glycogen in tubal epithelium with the 

 menstrual cycle, it is generally believed that 

 the maximal amount is present during the 

 follicular phase (Fawcett and Wislocki, 

 1950). 



It is generally assumed that the luminal 

 fluids of the oviducts and cornua undergo 

 cyclic changes, not only in amounts se- 

 creted, but also in their chemical composi- 

 tion. Such assumptions are based on very 

 tenuous evidence; actually these fluids have 

 received very little attention primarily be- 

 cause of the problems in obtaining ade- 

 quate samples and in correlating the chemi- 

 cal and physical characteristics of the tract 

 fluids with the endocrinologic and histo- 

 chemical activity of the cells forming the 

 stroma. With the development of a method 

 for the volumetric collection of tubal fluid 

 <Clewe and Mastroianni, 1960; Mastroi- 

 anni. Beer, Shah and Clewe, 1960), accurate 

 information with respect to the cjuantity 

 and nature of the secretion may now be ob- 

 tained. In the meantime we are dependent 

 on the reports by Bishop (1956a, c) and 

 Olds and Van Demark (1957a, b) who 

 have recently summarized and extended the 

 information available on the composition 

 and endocrine control of luminal fluids in 

 the female genital tracts of the rabbit and 

 cow. 



Observations on hydrogen ion concen- 

 trations of the fluids within the periovarial 

 sac, the dilated ampullae, and uterine cor- 



nua in the rat have revealed that the fluids 

 of the periovarial sac and oviduct have a 

 pH of approximately 8.05 ± 0.18, whereas 

 the mean pH of the cornual fluid is 7.74 ± 

 0.12 (Blandau, Jensen and Rumery, 1958). 

 The fluids from the reproductive tract were 

 significantly more basic than the peritoneal 

 fluids. The results from biochemical studies 

 on tubal fluid and ligation experiments re- 

 veal clearly that tubal fluid is the product 

 of the oviduct itself and that contributions 

 from the peritoneal cavity or uterus are 

 either minimal or absent. Much more in- 

 formation is necessary to learn the nature of 

 the molecular species present in the fluids of 

 the reproductive tract. Free electrophoretic 

 patterns of the cornual fluids of rats in heat 

 demonstrate the presence of four major 

 components in low concentrations. The lead- 

 ing major component has mobility values 

 somewhat faster than albumen and the re- 

 maining components have mobilities within 

 the range of normal serum proteins. Studies 

 of cornual fluids by paper electrophoresis, 

 however, suggest that the distribution of the 

 proteins is not the same as in rat serum 

 (Junge and Blandau, 1958). Previous ob- 

 servations on the washings of a sheep's ovi- 

 duct examined 45 to 60 minutes after death 

 showed a |)H of 6 to 6.4 during the diestrum 

 and 6.8 to 7.0 during estrus and the metes- 

 trum (Hadek, 1953). The pH of the uterine 

 fluids in cattle has been reported as ranging 

 from 5.8 to 7.0 with very minor changes 

 during the cycle (Sergin, Kuznecov, Koz- 

 lova and Nesmejanova, 1940). 



Respiratory differences between the epi- 

 thelium of the ampulla and the infundibu- 

 lum of the human oviduct have been studied 

 by Kneer, Burger and Simmer (1952) and 

 Mastroianni, Winternitz and Lowi (1958). 

 They found an increase in the respiratory 

 rate of botii segments during the follicular 

 phase, but not during the secretory phase. 

 During all phases of the cycle the oxygen 

 consumption of the epithelium of the am- 

 indla was consistently higher than that of 

 the epithelium of the infundibulum. Bishop 

 (1956b) measured oxygen tension in the 

 lumen of the rabbit oviduct by electrochem- 

 ical techniques and found that the luminal 

 environment is aerobic and that the oxygen 

 tension is in equilibrium with that of the 



