Archive for the ‘Ovarian’ Category

Before serum proteins reach the follicular antrum, several additional cellular layers must be crossed. Beyond the endothelium, blood proteins must traverse the theca interna, a layer composed of fibroblast-like, steroid-secreting, and transitional cells. Regulation of permeability of this layer could be similar to that of the vascular endothelium, in which intracellular microfilaments aid in contraction […]

These studies support the possibility that negatively charged proteins of intermediate size could traverse the endothelial cells only if there were a decrease in the net negative charge of the microvessel walls. It is therefore interesting that an increased blood flow appears to result in a decrease in negative surface charge at the luminal endothelial […]

Anatomical considerations indicate that translocation of a serum protein to the follicular antrum requires its passage through the following structures: 1) the capillary endothelium of the ovarian vasculature, 2) the theca interna, 3) the basement membrane, and 4) the membrana granulosa. It is possible that selectivity and permeability properties of the barrier could reside within […]

Earlier studies provided evidence that the blood-follicle barrier was located at the level of the ovarian microvasculature and demonstrated that it was freely permeable to most molecules below 70-300 kDa. Surprisingly, however, it was also shown that molecules of the lal family could enter the follicular fluid only after an ovulatory surge of gonadotropin. Thus, […]

Because administration of hCG was unable to stimulate the trans-barrier flux of IgG anionized with succinic anhydride, citraconylation was performed under conditions that blocked a smaller number of the lysine residues (—25%), producing a molecule similar in size and net negative charge to Ial. This anionized IgG molecule possessed a net negative charge (pi -6.3-6.5; […]

Cationization of Ial Promoted Its Entry into the Developing Follicle Previous studies have determined that Ial is necessary for stabilization of the cumulus extracellular matrix and for optimal ovulation. However, Ial has been found to enter developing follicles only after hCG administration or a natural ovulatory surge (Fig. 1C). To test the hypothesis that charge […]

Animal Experiments Mice received i.p. injections of 5 IU eCG. Forty-eight hours later, the mice received injections via the tail vein of 250-300 (xg of the following proteins in 150-|xl total volumes: cationized lal, rabbit IgG, anionized rabbit IgG, BSA, human a2-M, or cationized a2-M. Permeability of the blood-follicle barrier increases with the administration of […]

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