Archive for the ‘Epididymis by Testicular’ Category


DISCUSSION(8)

Since multiple РЕАЗ-binding motifs (5′-AGGAAG-3′) are present in promoter IV of the rat GGT gene , and PEA3 can bind to promoter IV of the rat GGT gene, it is proposed that PEA3 is involved in the transactivation of expression of GGT mRNA-IV in the rat initial segment. The DNA-binding and transactivation activity of PEA3 has been shown to be under the regulation of TPA, a tumor promoter, and growth factors including bFGF via a ras-raf-MAPK (mitogen-activated protein kinase) signal transductional pathway. In the present study, TPA and bFGF were found to regulate GGT catalytic activity and GGT protein level in the initial segment following EDL (Figs. 5-8). Since a-ra/and c-ra/-l have also been shown to be present in the initial segment, we hypothesize that a signal transduction pathway (bFGF—> bFGFR—>raf—>MAPK—»PEA3—>GGT mRNA-IV) is involved in regulation of the expression of GGT mRNA-IV, GGT catalytic activity, and GGT protein level in the rat initial segment. Further studies are underway to test this hypothesis. buy prednisone

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  • Considering increasing water absorption along the epididymal duct , the bFGF level in the epididymal lumen would be increased from the initial segment to the cauda. However, in the present study the bFGF protein level appeared to remain unchanged in the lumen from the proximal epididymal region to the distal epididymal region (Fig. 10A). An explanation for this result is that the luminal bFGF-like protein could have been reabsorbed from the initial segment to the caput and from caput to cauda via a receptor-mediated endocytosis pathway. Evidence to support this includes the presence of a bFGF receptor in the initial segment (unpublished results) and the increasing level of the 43-kDa bFGF-like protein in the homogenate from the initial segment to the cauda (Fig. 10B). Another possibility is that the 43-kDa bFGF-like protein could be hydrolyzed and degraded by proteases within the epididymal duct, resulting in the decrease of this protein in the lumen from the initial segment to the cauda. asthma inhalers

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  • DISCUSSION(6)

    Basic FGF-like proteins of 16 and 43 kDa were present in RTF and in the luminal fluid from various epididymal regions of the rat (Figs. 9 and 10). These results suggest that the 43-kDa and 16-kDa bFGF-like proteins in the initial segment could originate from the testis. Previous studies have shown that testicular factors (luminal fluid and spermatozoa) are depleted in the initial segment following 3-day EDL. In this study, the 43-kDa bFGF-like protein was not detected in the homogenate from the initial segment after 3-day EDL (Fig. 10, С and D). birth control pills

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  • Indeed, GGT protein level in the 3-day-EDL initial segment also returned to the sham value after bFGF treatment (Fig. 6). Basic FGF-like proteins were also shown to be present in rRTF and the initial segment (Figs. 9 and 10), and the level of bFGF-like protein decreased in the initial segment after 3-day EDL (Fig. 10C). These results suggest that effects of rRTF on GGT catalytic activity and GGT protein level in the 3-day-EDL initial segment are at least partially due to the presence of bFGF-like proteins. buy diabetes drugs

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  • DISCUSSION(4)

    Since oRTF contains growth factors and a number of growth factors are produced by the testis, it seems possible that growth factors could be candidates in RTF for factors that regulate GGT catalytic activity and GGT protein level in the initial segment. Possible candidates include bFGF and EGF, for several reasons: 1) both growth factors are produced by testis [32—40], 2) both bFGF and EGF activity have been observed in homogenates of human and/or bovine epididymis, 3) bFGF gene is expressed in the young rat epididymis, and 4) EGF receptor is present in mouse and monkey epididymis.

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  • Because of limited sources of rRTF, oRTF preparations were used to determine which factors in RTF were responsible for regulating GGT catalytic activity and protein level. Results showed that both charcoal-extracted oRTF and no-ABP oRTF recovered GGT catalytic activity and protein level in the initial segment following EDL (Figs. 3 and 4). As almost no ABP is present in no-ABP oRTF, and limited amounts of testosterone were present in charcoal-extracted oRTF and no-ABP oRTF, the recovery of GGT catalytic activity and GGT protein level in the 3-day-EDL initial segment by charcoal-extracted oRTF and no-ABP oRTF (Figs. 3 and 4) is probably not due to ABP or testosterone in these preparations. Buy Asthma Inhalers Online

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  • DISCUSSION(2)

    However, our results showed that GGT catalytic activity decreased by only about 20% 3-14 days after EDL as compared to the sham control value (Fig. 1). Even though the percentage of the decrease in GGT catalytic activity after EDL is in agreement with a previous report , it seems that GGT mRNA-IV plays only a partial role in maintaining normal GGT catalytic activity in the initial segment. This result also suggests that the other two forms of GGT mRNAs, which are expressed in the initial segment and whose expression is not under the regulation of testicular factors , are translated into protein for maintaining high GGT catalytic activity. In the caput and corpus regions, the decrease of GGT catalytic activity could be due to the decreased expression of GGT mRNA-II and GGT mRNA-III after EDL . In the cauda region, no changes in GGT catalytic activity and GGT mRNA expression were observed following EDL. buy ortho tri-cyclen

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  • The expression pattern of GGT catalytic activity along the rat epididymal duct in this study confirms previous observations that proximal regions of the rat epididymis have higher GGT catalytic activity than the distal regions . The values of GGT catalytic activity in the caput and cauda regions are also in agreement with previous reports . The decrease of GGT catalytic activity in the initial segment following 3 days of EDL (Fig. 1) is probably due to decreased GGT protein level (Fig. 2). buy ortho tri-cyclen online

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