Hormonal Control of “Tissue” Transglutaminase Induction during Programmed Cell Death in Frog Liver

摘要: Abstract In 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 specific induction “tissue” transglutaminase (tTG) gene. tTG protein specifically accumulates hepatocytes showing morphological features apoptosis. The hormone-dependent increase both was reproduced ovariectomized frogs. Treatment castrated animals with testosterone, progesterone inhibited PCD, thus indicating vivo drop circulating hormone signal favoring phase maternal after mating. Although an affinity-purified polyclonal antibody raised against mammalian reacts a 55- to 60-kDa protein, concomitant onset cleavage products were detected, suggesting proteolytic processing enzyme protein. These results represent first evidence occurring postvitellogenesis takes place this, together gene expression, regulated hormones.