1,720,996 research outputs found
Studio sull'attività degli enzimi di difesa contro i derivati citotossici dell'ossigeno durante lo sviluppo fetale in epatociti di ratto
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The simultaneous exposition of galactose and mannose-specific receptors on rat liver macrophages is developmentally regulated.
No full textHormonal control of "tissue" transglutaminase induction during programmed cell death in frog liver.
No full textIn this study, we show that sex hormones (testosterone, estradiol, and progesterone) act as physiological modulators of programmed cell death (PCD) during the frog liver involution observed postvitellogenesis. PCD in parenchymal cells is paralleled by the specific induction of the "tissue" transglutaminase (tTG) gene. tTG protein specifically accumulates in hepatocytes showing the morphological features of apoptosis. The hormone-dependent increase of both PCD and tTG was reproduced in ovariectomized frogs. Treatment of castrated animals with testosterone, estradiol, and progesterone inhibited the induction of both tTG and PCD, thus indicating that in vivo the drop in the circulating sex hormone is the signal favoring the involution phase of the maternal frog liver after mating. Although an affinity-purified polyclonal antibody raised against mammalian transglutaminase reacts in frog liver with a 55- to 60-kDa protein, concomitant with the onset of PCD, tTG cleavage products were detected, suggesting a proteolytic processing of the enzyme protein. These results represent the first evidence indicating that the physiological involution occurring postvitellogenesis of frog liver takes place by programmed cell death and that this, together with the concomitant induction of tTG gene expression, is regulated by sex hormones
Hormonal control of 'tissue' transglutaminase induction during programmed cell death in frog liver
No full textIn this study, we show that sex hormones (testosterone, estradiol, and progesterone) act as physiological modulators of programmed cell death (PCD) during the frog liver involution observed postvitellogenesis. PCD in parenchymal cells is paralleled by the specific induction of the "tissue" transglutaminase (tTG) gene. tTG protein specifically accumulates in hepatocytes showing the morphological features of apoptosis. The hormone-dependent increase of both PCD and tTG was reproduced in ovariectomized frogs. Treatment of castrated animals with testosterone, estradiol, and progesterone inhibited the induction of both tTG and PCD, thus indicating that in vivo the drop in the circulating sex hormone is the signal favoring the involution phase of the maternal frog liver after mating. Although an affinity-purified polyclonal antibody raised against mammalian transglutaminase reacts in frog liver with a 55- to 60-kDa protein, concomitant with the onset of PCD, tTG cleavage products were detected, suggesting a proteolytic processing of the enzyme protein. These results represent the first evidence indicating that the physiological involution occurring postvitellogenesis of frog liver takes place by programmed cell death and that this, together with the concomitant induction of tTG gene expression, is regulated by sex hormones
'Tissue' transglutaminase release from apoptotic cells into extracellular matrix during human liver fibrogenesis
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