Rats were implanted subcutaneously with silastic capsules containing 10 mg 17-β-estradiol. After 30, 60 and 120 days, their pituitary weights and plasma PRL levels were found to increase significantly. The administra...Rats were implanted subcutaneously with silastic capsules containing 10 mg 17-β-estradiol. After 30, 60 and 120 days, their pituitary weights and plasma PRL levels were found to increase significantly. The administration of β-estradiol also produced a marked rise of PRL mRNA concentrations in the rat total RNA, but the sharper rise of serum PRL levels indicates that estradiol not only promotes transcription of prolactin gene, but also improves the efficiency of translation of the transcription product.展开更多
Although many previous studies have suggested that estrogen functions as a cytoprotective agent under oxidative stress conditions, the underlying mechanism by which this effect is exerted remains to be elucidated. Thi...Although many previous studies have suggested that estrogen functions as a cytoprotective agent under oxidative stress conditions, the underlying mechanism by which this effect is exerted remains to be elucidated. This study assessed the effects of estradiol-17β （E2） （10^-8s M） on hypoxia-induced cell injury and its related signaling in primary cultured chicken hepatocytes. Hypoxic conditions were found to augment the level of DNA damage and to reduce cell viability and the level of [^3H]-thymidine incorporation, and these phenomena were prevented through treatment with E2. Hypoxia also increased caspase-3 expression, but showed no evidence of an influence on the expression of Bcl-2. However, E2 induced an increase in the level of Bcl-2 expression under hypoxic conditions and reduced the level of caspase-3 expression. The effects of E2 on Bcl-2 and caspase expression were blocked by ICI 182780 （E2 receptor （ER） antagonist, 10＂7 M）. In addition, hypoxia resulted in an increase in the intracellular reactive oxygen species （ROS） generated. These effects were blocked by E2, but not by E2-BSA and ICI 182780. Hypoxia also activated p38 mitogen-activated protein kinase （MAPK）, c-JUN N-terminal kinase/stress-activated protein kinase （JNK/SAPK） and nuclear factor-kB （NF-kB）. These effects were blocked by E2, but not by ICI 182780. The inhibition of p38 MAPK and JNK/SAPK blocked NF-kB activation. In conclusion, E2 was found to protect against hypoxia-induced cell injury in chicken hepatocytes through ER-mediated upregulation of Bcl-2 expression and through reducing the activity of ROS-dependent p38 MAPK, JNK/ SAPK and NF-kB.展开更多
Objective: To study the inhibition effects of estrogen on the production of corticotropin-releasing hormone in human placental cells. Methods: Primary cultured placental cells were treated by ICI182, 780, a complete E...Objective: To study the inhibition effects of estrogen on the production of corticotropin-releasing hormone in human placental cells. Methods: Primary cultured placental cells were treated by ICI182, 780, a complete ER antagonist , and Tamoxifen, an ERa-mixed agonist/antagonist and ERβ antagonist for 24 h. The supernatant was havested for the radioimmunoassay of CRH. Results: 17β-estradiol inhibited the secretion of corticotropin-releasing hormone in human placental (P<0.05). ICI182, 780 stimulated the secretion of corticotropin-releasing hormone in human placental (P<0.05). Conclusion: Estrogen represses the synthesis and secretion of corticotropin-releasing hormone in human placental, which is possibly mediated by ERa.展开更多
Objective To explore the potential mechanism of breakthrough bleeding associated with progestin with in vitro methods.Methods The isolation and culture of human endometrial endothelial cells(HEECs)was performed with t...Objective To explore the potential mechanism of breakthrough bleeding associated with progestin with in vitro methods.Methods The isolation and culture of human endometrial endothelial cells(HEECs)was performed with the method established in our laboratory.The content and activity of urokinase-type plasminogen activator(uPA)and the content of plasminogen activator inhibitor-1(PAI-1)in cell supernatants after incubated with different concentrations of progesterone(0-5 μmol/L)and 17β-estradiol(0,0.1,or 1 nmol/L)were measured by method of ELISA.Apoptosis rate of HEECs was measured by flow cytometry.Viable cell count was measured by MTT.Results The increased level of progesterone(0.5-5 μmol/L)combined with 17β-estradiol elevated content and activity of uPA while the production of PAI-1 remained unchanged.The apoptosis of HEECs was inhibited along with the increment of total viable cell counts at higher concentrations of progesterone with 17β-estradiol.Conclusion The inhibition of apoptosis and increased content and activity of uPA may contribute to the occurrence of irregular bleeding associated with progestin use to some extent.展开更多
Sprague-Dawley rats were implanted with silastic capsules containing β-estradiol. After 60 days, their pituitary weights, serum prolactin contentsand transcription level of c-myc proto-oncogene were found increasedsi...Sprague-Dawley rats were implanted with silastic capsules containing β-estradiol. After 60 days, their pituitary weights, serum prolactin contentsand transcription level of c-myc proto-oncogene were found increasedsignificantly. It was also found that the anterior pituitary cells proliferatedsignificantly, but their differentiation was suppressed.展开更多
文摘Rats were implanted subcutaneously with silastic capsules containing 10 mg 17-β-estradiol. After 30, 60 and 120 days, their pituitary weights and plasma PRL levels were found to increase significantly. The administration of β-estradiol also produced a marked rise of PRL mRNA concentrations in the rat total RNA, but the sharper rise of serum PRL levels indicates that estradiol not only promotes transcription of prolactin gene, but also improves the efficiency of translation of the transcription product.
文摘Although many previous studies have suggested that estrogen functions as a cytoprotective agent under oxidative stress conditions, the underlying mechanism by which this effect is exerted remains to be elucidated. This study assessed the effects of estradiol-17β （E2） （10^-8s M） on hypoxia-induced cell injury and its related signaling in primary cultured chicken hepatocytes. Hypoxic conditions were found to augment the level of DNA damage and to reduce cell viability and the level of [^3H]-thymidine incorporation, and these phenomena were prevented through treatment with E2. Hypoxia also increased caspase-3 expression, but showed no evidence of an influence on the expression of Bcl-2. However, E2 induced an increase in the level of Bcl-2 expression under hypoxic conditions and reduced the level of caspase-3 expression. The effects of E2 on Bcl-2 and caspase expression were blocked by ICI 182780 （E2 receptor （ER） antagonist, 10＂7 M）. In addition, hypoxia resulted in an increase in the intracellular reactive oxygen species （ROS） generated. These effects were blocked by E2, but not by E2-BSA and ICI 182780. Hypoxia also activated p38 mitogen-activated protein kinase （MAPK）, c-JUN N-terminal kinase/stress-activated protein kinase （JNK/SAPK） and nuclear factor-kB （NF-kB）. These effects were blocked by E2, but not by ICI 182780. The inhibition of p38 MAPK and JNK/SAPK blocked NF-kB activation. In conclusion, E2 was found to protect against hypoxia-induced cell injury in chicken hepatocytes through ER-mediated upregulation of Bcl-2 expression and through reducing the activity of ROS-dependent p38 MAPK, JNK/ SAPK and NF-kB.
基金Supported by National Natural Science Foundation of China(No.39870300)
文摘Objective: To study the inhibition effects of estrogen on the production of corticotropin-releasing hormone in human placental cells. Methods: Primary cultured placental cells were treated by ICI182, 780, a complete ER antagonist , and Tamoxifen, an ERa-mixed agonist/antagonist and ERβ antagonist for 24 h. The supernatant was havested for the radioimmunoassay of CRH. Results: 17β-estradiol inhibited the secretion of corticotropin-releasing hormone in human placental (P<0.05). ICI182, 780 stimulated the secretion of corticotropin-releasing hormone in human placental (P<0.05). Conclusion: Estrogen represses the synthesis and secretion of corticotropin-releasing hormone in human placental, which is possibly mediated by ERa.
文摘Objective To explore the potential mechanism of breakthrough bleeding associated with progestin with in vitro methods.Methods The isolation and culture of human endometrial endothelial cells(HEECs)was performed with the method established in our laboratory.The content and activity of urokinase-type plasminogen activator(uPA)and the content of plasminogen activator inhibitor-1(PAI-1)in cell supernatants after incubated with different concentrations of progesterone(0-5 μmol/L)and 17β-estradiol(0,0.1,or 1 nmol/L)were measured by method of ELISA.Apoptosis rate of HEECs was measured by flow cytometry.Viable cell count was measured by MTT.Results The increased level of progesterone(0.5-5 μmol/L)combined with 17β-estradiol elevated content and activity of uPA while the production of PAI-1 remained unchanged.The apoptosis of HEECs was inhibited along with the increment of total viable cell counts at higher concentrations of progesterone with 17β-estradiol.Conclusion The inhibition of apoptosis and increased content and activity of uPA may contribute to the occurrence of irregular bleeding associated with progestin use to some extent.
文摘Sprague-Dawley rats were implanted with silastic capsules containing β-estradiol. After 60 days, their pituitary weights, serum prolactin contentsand transcription level of c-myc proto-oncogene were found increasedsignificantly. It was also found that the anterior pituitary cells proliferatedsignificantly, but their differentiation was suppressed.
