Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.6.1 (sulfatase)
 3,205 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To gain further information on the biological role of the high amounts of conjugated estrone (E1S) secreted by the bovine placenta, an in vitro assay system was developed to measure oestrogen sulfotransferase (OST) and oestrogen sulfatase (OS) activities in caruncular and cotyledonary homogenates and the respective subcellular fractions. Placental tissue was obtained from 150 (n = 3), 220 (n = 4), 240 (n = 3) and 270 days (n = 3) pregnant and parturient cows (n = 4). 3H-E1 and 3H-E1S served as substrates and 4-nitrophenyl sulfate potassium salt was used as a competitive inhibitor to block OS when testing for OST activity. OST-activity did not change during pregnancy and parturition and was higher (p < 0.001) in cotyledonary than in caruncular tissue with mean conversions (median) of 61.8% and 41.6% after 30 min of homogenate incubation. On a subcellular level OST-activity was clearly associated with the cytosol. OS-activity was higher (p < 0.001) in caruncular than in cotyledonary homogenates; it was constant during pregnancy (median of conversion: 88.0% and 66.4%, resp.), but was significantly decreased (p < 0.05) at parturition (median of conversion: 48.1% and 30.6%, resp.). On a subcellular level in both the cotyledon and the caruncle highest OS-activities were detected in the microsomal and the mitochondrial fractions. The decreased placentomal OS-activities in parturient cows are inconsistent with a substantial role of OS in the prepartal increase of free oestrogens. These results also suggest that bovine placental oestrogens may largely exert their action locally within the placentomes during most time of gestation as the enzymes catalyzing sulfoconjugation (i.e. inactivation of free oestrogens) and desulfation (i.e. activation of conjugated oestrogens) are expressed in close proximity to each other. In this respect the finding of oestrogen receptors in caruncular stromal cells is of particular interest.
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PMID:Investigations on the activity of bovine placental oestrogen sulfotransferase and -sulfatase from midgestation to parturition. 1150 54

Apart from estrone-3-sulfate (E1S) the bovine placenta produces progesterone (P4), though the corpus luteum is the major source of P4 responsible for maintaining pregnancy. So far the biological function of placental steroids in cattle is largely unknown. However, since the local availability of free estrone (E1) in the placenta seems to be controlled by sulfatase and sulfotranferase, the hypothesis was developed that placental estrogens and P4 might act as local regulatory factors. To test for such a function placentomes from 150, 220, 240, 270 days (D) pregnant and parturient cows were screened immunohistochemically for progesterone and estrogen receptors (PR, ER). PR were found at all stages in the caruncle in stromal cells and capillary pericytes but only at parturition in arterial walls. Percentage of PR-positive caruncular stromal cells (CSC) increased (P<0.05) from 51.8+/-2.6% at D150 to 58.9+/-1.8% at parturition. ER were detected in CSC, caruncular epithelial (CE) cells and in caruncular capillary pericytes. Mean percentage of ER-positive CSC decreased from 39.0+/-5.9% in pregnant cows to 17.5+/-8.3% at parturition (P<0.05). In CE all cells exhibited positive signals with the exception of those immediately surrounding large primary chorionic villi. Proliferation was assessed immunohistochemically by determining the percentage of Ki67-antigen positive cells. Highest values (P<0.001) were obtained for CE (58.0-68.3%), followed by the trophoblast (23.3-25.4%), CSC (10.6-45.3%) and the stroma of the chorionic villi (2.9-10.5%). A transient depression of proliferation in CSC between D150-270 (P<0.05) paralleled local estrogen tissue concentrations. The results suggest that placental estrogens and P4 are important factors controlling caruncular growth, differentiation and function.
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PMID:The bovine placenta; a source and target of steroid hormones: observations during the second half of gestation. 1214 47