BIOCHEMICAL REGULATION OF ESTRADIOL BINDING IN HUMAN ENDOMETRIUM.
Item
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Title
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BIOCHEMICAL REGULATION OF ESTRADIOL BINDING IN HUMAN ENDOMETRIUM.
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Identifier
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AAI8409383
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identifier
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8409383
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Creator
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BLUMENTHAL, ROSALYN DIANE.
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Contributor
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Erlio Gurpide
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Date
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1984
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Language
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English
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Publisher
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City University of New York.
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Subject
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Biology, Animal Physiology
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Abstract
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The addition of molybdate to intact or homogenized cells of the endometrial adenocarcinoma line, HEC-1, or to homogenates of normal endometrium during incubation with 3H-estradiol at 4C caused significant increases in specific cytoplasmic E2 binding. The effects of molybdate appear to involve activation of E2 binding rather than protection from destabilization of binding. Fractionation of cell homogenates and recombination of subfractions revealed that molybdate (MoO4=) requires cytosolic factors as well as factors associated with the cell membrane to exert its effect. The addition of ATP, GTP or cGMP to homogenates of Human Endometrial Cancer (HEC) cells, normal or neoplastic endometrium, increased E2 binding to levels comparable to those obtained by addition of MoO4=. In contrast, the addition of cAMP lowered E2 binding and counteracted the effects of MoO4=, ATP, GTP and cGMP. The binding sites generated by the addition of cGMP were found to sediment in the 8S and 4S regions of low salt glycerol gradients. The effects of ATP and GTP were elicited only in the presence of cell membrane factors, whereas both cyclic nucleotides exert their respective effects when added directly to cytosol. It is hypothesized that MoO4=, ATP and GTP affect specific estrogen binding primarily by increasing the cGMP concentration through processes involving a plasma membrane bound guanylate cyclase. The cNMP effects were rapid, reaching completion in < 15 minutes in the presence of Mg('++), Mn('++) or Ca('++). Changes in estrogen binding (EB) levels were not observed if cNMPs were added to ATP depleted cytosol but responsiveness to the cNMPs was restored upon addition of exogenous ATP.;Fluctuations in estrogen binding by HEC cells in culture have been correlated with rapid changes in the ratio of the levels of cAMP/cGMP. In addition, the increases in EB induced by molybdate have been inversely related to changes in the cAMP/cGMP ratio.;The ATP requirement for cNMP activity and the pattern of dependence on divalent cation concentrations suggest that cGMP and cAMP effects on EB may be mediated by the action of cyclic nucleotide dependent protein kinases.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
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Program
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Biomedical Sciences
