Further studies were conducted to define an indispensable role of uterine bicarbonate secretion at pre-implantation for the success of blastocyst implantation. The in vitro implantation experiments showed that only when cultured in bicarbonate-containing medium, the blastocysts exhibited normal rate of attachment and outgrowth level. The forskolin-induced endometrial bicarbonate secretion measured by the Isc on pregnant day 4 was almost abolished by CA inhibitor acetazolamide. The efflux of intracellular bicarbonate, measured by intracellular pH-sensitive dye, was blocked by CFTR inhibitor, NPPB, and SLC26a6 inhibitor, DIDS, indicating their involvement in mediating uterine bicarbonate secretion. / In conclusion, the present findings have demonstrated an important role of CFTR in formation of optimal uterine fluid, in terms of both volume and composition, which is crucial for various reproductive events occurring in the uterus. Deviation from the normal uterine fluid composition and volume due to defects in CFTR function or abnormal regulation under pathological conditions, such as CF and genital bacteria infection, probably leads to infertility. The information obtained may provide insight into regulatory mechanism underlying fertility and infertility, as well as the rationale for development of treatment methods for female infertility and new strategies for female contraception. (Abstract shortened by UMI.) / The last part of the study was to demonstrate possible cause of infertility by disturbance of uterine fluid dynamic due to abnormal expression of CFTR using a model of uterine Chlamydia (C.) trachomatis infection, the most common infection-related sterility with the underlying cause unexplained. Uterine C. trachomatis infection induced up-regulated expression of CFTR with enhanced electrolyte and fluid transport as demonstrated by the increase in the cAMP-dependent Isc and uterine wet weight with obvious fluid accumulation in the lumen at diestrus stage, during which the endometrium normally undergoes a series of changes preparing for blastocyst implantation with minimum CFTR expression and uterine fluid volume. The abnormal uterine fluid accumulation upon uterine C. trachomatis infection significantly reduced implantation rate in uterine C. trachomatis infection mouse model. / The present study was aimed to elucidate the cellular and molecular mechanisms underlying the CFTR-related reproductive events in physiological and pathological conditions by using a variety of techniques, including RT-PCR, Western blot, intracellular and extracellular pH measurements, and the short-circuit current (Isc) measurement, in conjunction with mouse primary culture of endometrial cells and blastocyst, as well as several animal models including CF mouse, mouse uterine infectious model and overyectomized (OVX) mouse, etc. / We first examined dynamic changes in uterine bicarbonate secretion, as indicated by bicarbonate-dependent forskolin-induced Isc and epithelial surface pH measurement, and the expression profile of candidate genes and proteins known to be involved in bicarbonate secretion throughout the estrous cycle in mouse uterus. The results showed that the maximum mRNA and protein levels of CFTR, SLC26a6, carbonic anhydrase (CA)2 and CA12 were observed at proestrus stage and/or estrus stages. Luminal surface pH measured by 5-N-hexadecanoyl-aminofluorescein (HAF) showed that the basal endometrial epithelial surface pH at estrus stage was significantly higher than that in diestrus, which could be reduced significantly by CFTR inhibitor DPC, SLC26a6 inhibitor 4',4'-Diisothiocyanostilbene-2',2' Disulfonic Acid (DIDS) and CA suppressor acetazolamide. In the ovariectimized (OVX) mice and primary culture of endometrial cells, estrogen could induce up-regulation of CFTR, SLC26a6, CA2 and CA12 expression with corresponding increase in the bicarbonate-dependent Isc, suggesting a novel role of estrogen in regulating uterine bicarbonate secretion. / He, Qiong. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3247. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 163-176). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.