<abstract>Ageing in man is associated with a decline in testosterone following changes in the hypothalamo-pituitary testicular axis. This may offset the physiologic equilibrium between oestrogen and androgen and...<abstract>Ageing in man is associated with a decline in testosterone following changes in the hypothalamo-pituitary testicular axis. This may offset the physiologic equilibrium between oestrogen and androgen and at some point when the ratio of free testosterone to oestradiol reaches a critical level, the oestrogenic gonadotropin suppressive effect predominates with decreased release of FSH and LH. Adding to this endocrinal complexity is the continued peripheral conversion to oestradiol through aromatisation. Although the androgen deficiency is not the sole cause for impotence in the elderly, there is a gradual decrease in nocturnal penile tumescence (NPT) and spontaneous morning erections with ageing. Despite the age related increase in oestrogen levels, the information on the pathophysiological role of the 'female hormone' in erectile dysfunction has been scanty. Together with our identification of oestrogen receptors within the penile cavernosum, we have delineated dysfunctional changes on male erection mediated by oestradiol. These findings parallel the recent concerns over environmental oestrogens on fertility declines in young men. Oestrogenic activity is also present in plants and thereby in human diet. These phytoestrogens are structurally and functionally similar to oestradiol and more potent than the environmental oestrogenic chemicals such as organochlorine and phenolic compounds. Thus in the light of growing concerns of possible compromising effects on sexuality by endogenous and environmental oestrogens, we are faced with the scientific need to delineate their role on the mechanism of male erectile pathway in health and disease for clinical correlates and prognostics.展开更多
To study the effects of oestrogcn on ischemia-induced neurogenesis in the hippocampal dentate gyms, thirty-two adult male rats were randomly divided into four groups： the control surgery group with eestrogen administ...To study the effects of oestrogcn on ischemia-induced neurogenesis in the hippocampal dentate gyms, thirty-two adult male rats were randomly divided into four groups： the control surgery group with eestrogen administration （SE）, the control surgery group with normal saline administration （SN）, the middle cerebral artery occlusion （MCAO） group with oestrogen administration （ME） and the MCAO group with normal saline administration （MN）. The MCAO rats were occluded for 90 rain by an intraluminal filament and then recirculated. After 1, 3, 12, 24 and 28 h of MCAO, the rats of the four groups were killed to investigate the infarct volume, apoptosis and neurogenesis. The cerebral infarct volume in the ME group was significantly smaller than that of the MN group （P 〈 0.05）. No significant cell loss was seen in the dentate gyms. Cerebral ischemia led to increased neurogenosis, which is independent of cell death in the ipsilateral dentate gyrus（P 〈 0.05）. BrdU-pesitive cells in the ipsilateral dentate gyms of the ME group were significantly increased when compared with those of the MN group（P 〈 0.05）. In the SE group, BrdU-positive cells in both the ipsilateral and contralateral dentate gyms, were increased when compared with those of the SN group （ P 〈 0.05 ）. We concluded that ocstregen plays an important role in neurogenesis, which is independent of ischemia-induced by MCAO in the hippocampal dentate gyms of rats.展开更多
The androgen receptor （AR） plays a critical role in prostate cancer development and progression. This study aimed to use a computerized docking approach to examine the interactions between the human AR and phytooest...The androgen receptor （AR） plays a critical role in prostate cancer development and progression. This study aimed to use a computerized docking approach to examine the interactions between the human AR and phytooestrogens （genistein, daidzein, and flavone） and xeno-oestrogens （bisphenol A, 4-nonylphenol, dichlorodiphenyl trichloroethane [DDT], diethylstilbestrol [DES]）. The predicted three-dimensional structure of AR and androgens was established using X-ray diffraction. The binding of four xeno-oestrogens and three phyto-oestrogens to AR was analysed. The steroids estradiol and dihydrotestosterone （DHT） were used as positive controls and thyroxine as negative control. All the ligands shared the same binding site except for thyroxine. The endogenous hormones DHT and 17β-oestradiol showed the strongest binding with the lowest affinity energy （〈 -10 kcal mol-1）. All three phyto- oestrogens and two xeno-oestrogens （bisphenol A and DES） showed strong binding to AR. The affinities offlavone, genistein, and daidzein were between -8.8 and -8.5 kcal mol 1, while that of bisphenol A was -8.1 kcal mol-l and DES -8.3 kcal mol-1. Another two xeno-oestrogens, 4-nonylphenol and DDT, although they fit within the binding domain of AR, showed weak affinity （-6.4 and -6.7 kcal mol 1, respectively）. The phyto-oestrogens genistein, daidzein and flavone, and the xeno-oestrogens bisphenol A and DES can be regarded as androgenic effectors. The xenooestrogens DDT and 4-nonylphenol bind only weakly to AR.展开更多
AIM To evaluate sex differences and the effects of oestrogen administration in rat gastric mucosal defence.METHODS Sex differences in gastric mucus thickness and accumulation rate, absolute gastric mucosal blood flow ...AIM To evaluate sex differences and the effects of oestrogen administration in rat gastric mucosal defence.METHODS Sex differences in gastric mucus thickness and accumulation rate, absolute gastric mucosal blood flow using microspheres, the integrity of the gastric mucosal epithelium in response to a chemical irritant and the effects of oestrogen administration on relative gastric mucosal blood flow in an acute setting was assessed in an in vivo rat experimental model. Subsequently, sex differences in the distribution of oestrogen receptors and calcitonin gene related peptide in the gastric mucosa of animals exposed to oestrogen in the above experiments was evaluated using immunohistochemistry.RESULTS The absolute blood flow in the GI-tract was generally higher in males, but only significantly different in the corpus part of the stomach (1.12 ± 0.12 m L/min·g in males and 0.51 ± 0.03 m L/min·g in females) (P = 0.002). After removal of the loosely adherent mucus layer the thickness of the firmly adherent mucus layer in males and females was 79 ± 1 μm and 80 ± 3 μm respectively. After 60 min the mucus thickness increased to 113 ± 3 μm in males and 121 ± 3 μm in females with no statistically significant difference seen between the sexes. Following oestrogen administration(0.1 followed by 1 μg/kg·min), mean blood flow in the gastric mucosa decreased by 31% [68 ± 13 perfusion units (PFU)] in males which was significantly different compared to baseline(P = 0.02). In females however, mean blood flow remained largely unchanged with a 4% (5 ± 33 PFU) reduction. The permeability of the gastric mucosa increased to a higher level in females than in males (P = 0.01) after taurocholate challenge. However, the calculated mean clearance increase did not significantly differ between the sexes [0.1 ± 0.04 to 1.1 ± 0.1 m L/min·100 g in males and 0.4 ± 0.3 to 2.1 ± 0.3 m L/min·100 g in females(P = 0.065)]. There were no significant differences between 17β-Estradiol treated males (mean ratio of positive staining ± SEM)(0.06 ± 0.07) and females(0.11 ± 0.11) in the staining of ERα (P = 0.24). Also, there were no significant differences between 17β-Estradiol treated males (0.18 ± 0.21) and females (0.06 ± 0.12) in the staining of ERβ (P = 0.11). Finally, there were no significant differences between 17β-Estradiol treated males (0.04 ± 0.05) and females (0.11 ± 0.10) in the staining of CGRP(P = 0.14).CONCLUSION Gastric mucosal blood flow is higher in male than in female rats and is reduced in male rats by oestrogen administration.展开更多
Background Recent studies have suggested that estrogens are involved in normal and abnormal prostate growth, though their exact role is still controversial. Oestrogens exert inhibitory and stimulatory effects on prost...Background Recent studies have suggested that estrogens are involved in normal and abnormal prostate growth, though their exact role is still controversial. Oestrogens exert inhibitory and stimulatory effects on prostate gland, but the expression of oestrogen receptor-α （ERα） and oestrogen receptor-β （ERβ） in malignant prostate tissue remains unresolved. We determined ERa and ERβ in prostate cancer and investigated the relationship between expression of ER and pathological features of prostate carcinoma. Methods Thirty-two cases of prostate cancer, 12 cases of normal prostate tissue and 32 cases of benign prostate hyperplasia were analyzed for the expression of ERa and ERβ using semiquantitative, reverse transcription polymerase chain reaction （RT-PCR） and the products sequenced. Results Comparisons of the normal, hyperplastic and tumour prostate tissues indicated an overexpression of ERa in tumour specimens （P〈0.01）. However, the expression of ERβ significantly reduced in tumour tissues compared with normal and hyperplastic specimens （P〈0.01）, suggesting that severe pathological features of prostate cancer were associated with lower ERβ expression. Spearman analysis showed negative correlation between ERβ expression and tumour stage, grade （-0.67, -0.43, respectively, both P〈0.05）, and a positive correlation between ERα expression and tumour stage, grade （0.51, 0.57, respectively, both P〈0.01）. Our analysis also showed that hormone refractory, prostate cancer, compared with hormone dependent, prostate cancer, displayed a decreased expression of ERβ （P〈0.01） and an increased expression of ERa. Conclusions ERα and ERβ may play important roles in the development of prostate cancer. The decrease in ERβ expression is associated with higher Gleason grade tumours and prostate cancer with higher metastatic potential. The loss of ERβ could be one of the key processes leading to uncontrolled growth of prostate epithelial cells.展开更多
Objective:To investigate the potential of N-acetylcysteine(NAC)and zinc sulphate(ZnSO_(4))in mitigating reproductive dysfunction caused by di-2-ethylhexyl phthalate(DEHP)in rats and to understand the underlying mechan...Objective:To investigate the potential of N-acetylcysteine(NAC)and zinc sulphate(ZnSO_(4))in mitigating reproductive dysfunction caused by di-2-ethylhexyl phthalate(DEHP)in rats and to understand the underlying mechanisms,specifically oxidative stress and sex hormone receptor activity.Methods:Thirty-five male Wistar rats were randomly divided into five equal groups(n=7 per group).Group 1 was administered 0.5 mL of distilled water and served as the control group.Group 2 was given only DEHP(750 mg/kg/day),while group 3,4 and 5 were given DEHP(750 mg/kg/day)plus NAC(100 mg/kg/day),DEHP(750 mg/kg/day)plus ZnSO_(4)(0.5 mg/kg/day),and DEHP(750 mg/kg/day)plus NAC(100 mg/kg/day)as well as ZnSO_(4)(0.5 mg/kg/day),respectively.All treatments lasted for 21 days.Samples were obtained after the rats were sacrificed,and hormones levels in the serum and markers of oxidative stress in the testicles were analyzed using the enzyme-linked immunosorbent assay.The amount of androgen receptors in the testicles was determined by immunohistochemistry,and the susceptibility of testosterone and DEHP to bind to androgen receptor and 5α-reductase was determined by molecular docking studies.Results:DEHP decreased reproductive hormones,testicular antioxidant enzymes,increased malondialdehyde levels,and negatively impacted histology of the pituitary and testes.NAC or ZnSO_(4) treatment showed a marked improvement in testicular antioxidant status and hormone levels,as well as a positive effect on the histology of the pituitary and testes.The combination of both treatments appeared to be more effective.The affinity of DEHP to bind to androgen receptors may lead to disruption of androgen receptor signaling,which can further result in dysfunction of hormones related to androgen.However,NAC is more likely to form stronger binding interactions with follicle stimulating hormone and luteinizing hormone receptors,as well as gonadotropin-releasing hormone receptors,when compared to DEHP.Conclusions:The possibility that NAC and ZnSO_(4) could downregulate DEHP-induced sex hormone changes is suggested by their potential to reduce toxicity.展开更多
文摘<abstract>Ageing in man is associated with a decline in testosterone following changes in the hypothalamo-pituitary testicular axis. This may offset the physiologic equilibrium between oestrogen and androgen and at some point when the ratio of free testosterone to oestradiol reaches a critical level, the oestrogenic gonadotropin suppressive effect predominates with decreased release of FSH and LH. Adding to this endocrinal complexity is the continued peripheral conversion to oestradiol through aromatisation. Although the androgen deficiency is not the sole cause for impotence in the elderly, there is a gradual decrease in nocturnal penile tumescence (NPT) and spontaneous morning erections with ageing. Despite the age related increase in oestrogen levels, the information on the pathophysiological role of the 'female hormone' in erectile dysfunction has been scanty. Together with our identification of oestrogen receptors within the penile cavernosum, we have delineated dysfunctional changes on male erection mediated by oestradiol. These findings parallel the recent concerns over environmental oestrogens on fertility declines in young men. Oestrogenic activity is also present in plants and thereby in human diet. These phytoestrogens are structurally and functionally similar to oestradiol and more potent than the environmental oestrogenic chemicals such as organochlorine and phenolic compounds. Thus in the light of growing concerns of possible compromising effects on sexuality by endogenous and environmental oestrogens, we are faced with the scientific need to delineate their role on the mechanism of male erectile pathway in health and disease for clinical correlates and prognostics.
文摘To study the effects of oestrogcn on ischemia-induced neurogenesis in the hippocampal dentate gyms, thirty-two adult male rats were randomly divided into four groups： the control surgery group with eestrogen administration （SE）, the control surgery group with normal saline administration （SN）, the middle cerebral artery occlusion （MCAO） group with oestrogen administration （ME） and the MCAO group with normal saline administration （MN）. The MCAO rats were occluded for 90 rain by an intraluminal filament and then recirculated. After 1, 3, 12, 24 and 28 h of MCAO, the rats of the four groups were killed to investigate the infarct volume, apoptosis and neurogenesis. The cerebral infarct volume in the ME group was significantly smaller than that of the MN group （P 〈 0.05）. No significant cell loss was seen in the dentate gyms. Cerebral ischemia led to increased neurogenosis, which is independent of cell death in the ipsilateral dentate gyrus（P 〈 0.05）. BrdU-pesitive cells in the ipsilateral dentate gyms of the ME group were significantly increased when compared with those of the MN group（P 〈 0.05）. In the SE group, BrdU-positive cells in both the ipsilateral and contralateral dentate gyms, were increased when compared with those of the SN group （ P 〈 0.05 ）. We concluded that ocstregen plays an important role in neurogenesis, which is independent of ischemia-induced by MCAO in the hippocampal dentate gyms of rats.
基金This study was supported by Ministry of Science and Technology （No. 2010DFA31430）, the National Natural Science Foundation of China （No. 30871301, 30700827）, Ministry of Education of China （No. 108047）, Jilin Provincial Science ＆ Technology Department （No. 20070719, 20080731, 200905116）. We thank Mr Michael Hoyt, who critically read and revised our manuscript.
文摘The androgen receptor （AR） plays a critical role in prostate cancer development and progression. This study aimed to use a computerized docking approach to examine the interactions between the human AR and phytooestrogens （genistein, daidzein, and flavone） and xeno-oestrogens （bisphenol A, 4-nonylphenol, dichlorodiphenyl trichloroethane [DDT], diethylstilbestrol [DES]）. The predicted three-dimensional structure of AR and androgens was established using X-ray diffraction. The binding of four xeno-oestrogens and three phyto-oestrogens to AR was analysed. The steroids estradiol and dihydrotestosterone （DHT） were used as positive controls and thyroxine as negative control. All the ligands shared the same binding site except for thyroxine. The endogenous hormones DHT and 17β-oestradiol showed the strongest binding with the lowest affinity energy （〈 -10 kcal mol-1）. All three phyto- oestrogens and two xeno-oestrogens （bisphenol A and DES） showed strong binding to AR. The affinities offlavone, genistein, and daidzein were between -8.8 and -8.5 kcal mol 1, while that of bisphenol A was -8.1 kcal mol-l and DES -8.3 kcal mol-1. Another two xeno-oestrogens, 4-nonylphenol and DDT, although they fit within the binding domain of AR, showed weak affinity （-6.4 and -6.7 kcal mol 1, respectively）. The phyto-oestrogens genistein, daidzein and flavone, and the xeno-oestrogens bisphenol A and DES can be regarded as androgenic effectors. The xenooestrogens DDT and 4-nonylphenol bind only weakly to AR.
文摘AIM To evaluate sex differences and the effects of oestrogen administration in rat gastric mucosal defence.METHODS Sex differences in gastric mucus thickness and accumulation rate, absolute gastric mucosal blood flow using microspheres, the integrity of the gastric mucosal epithelium in response to a chemical irritant and the effects of oestrogen administration on relative gastric mucosal blood flow in an acute setting was assessed in an in vivo rat experimental model. Subsequently, sex differences in the distribution of oestrogen receptors and calcitonin gene related peptide in the gastric mucosa of animals exposed to oestrogen in the above experiments was evaluated using immunohistochemistry.RESULTS The absolute blood flow in the GI-tract was generally higher in males, but only significantly different in the corpus part of the stomach (1.12 ± 0.12 m L/min·g in males and 0.51 ± 0.03 m L/min·g in females) (P = 0.002). After removal of the loosely adherent mucus layer the thickness of the firmly adherent mucus layer in males and females was 79 ± 1 μm and 80 ± 3 μm respectively. After 60 min the mucus thickness increased to 113 ± 3 μm in males and 121 ± 3 μm in females with no statistically significant difference seen between the sexes. Following oestrogen administration(0.1 followed by 1 μg/kg·min), mean blood flow in the gastric mucosa decreased by 31% [68 ± 13 perfusion units (PFU)] in males which was significantly different compared to baseline(P = 0.02). In females however, mean blood flow remained largely unchanged with a 4% (5 ± 33 PFU) reduction. The permeability of the gastric mucosa increased to a higher level in females than in males (P = 0.01) after taurocholate challenge. However, the calculated mean clearance increase did not significantly differ between the sexes [0.1 ± 0.04 to 1.1 ± 0.1 m L/min·100 g in males and 0.4 ± 0.3 to 2.1 ± 0.3 m L/min·100 g in females(P = 0.065)]. There were no significant differences between 17β-Estradiol treated males (mean ratio of positive staining ± SEM)(0.06 ± 0.07) and females(0.11 ± 0.11) in the staining of ERα (P = 0.24). Also, there were no significant differences between 17β-Estradiol treated males (0.18 ± 0.21) and females (0.06 ± 0.12) in the staining of ERβ (P = 0.11). Finally, there were no significant differences between 17β-Estradiol treated males (0.04 ± 0.05) and females (0.11 ± 0.10) in the staining of CGRP(P = 0.14).CONCLUSION Gastric mucosal blood flow is higher in male than in female rats and is reduced in male rats by oestrogen administration.
文摘Background Recent studies have suggested that estrogens are involved in normal and abnormal prostate growth, though their exact role is still controversial. Oestrogens exert inhibitory and stimulatory effects on prostate gland, but the expression of oestrogen receptor-α （ERα） and oestrogen receptor-β （ERβ） in malignant prostate tissue remains unresolved. We determined ERa and ERβ in prostate cancer and investigated the relationship between expression of ER and pathological features of prostate carcinoma. Methods Thirty-two cases of prostate cancer, 12 cases of normal prostate tissue and 32 cases of benign prostate hyperplasia were analyzed for the expression of ERa and ERβ using semiquantitative, reverse transcription polymerase chain reaction （RT-PCR） and the products sequenced. Results Comparisons of the normal, hyperplastic and tumour prostate tissues indicated an overexpression of ERa in tumour specimens （P〈0.01）. However, the expression of ERβ significantly reduced in tumour tissues compared with normal and hyperplastic specimens （P〈0.01）, suggesting that severe pathological features of prostate cancer were associated with lower ERβ expression. Spearman analysis showed negative correlation between ERβ expression and tumour stage, grade （-0.67, -0.43, respectively, both P〈0.05）, and a positive correlation between ERα expression and tumour stage, grade （0.51, 0.57, respectively, both P〈0.01）. Our analysis also showed that hormone refractory, prostate cancer, compared with hormone dependent, prostate cancer, displayed a decreased expression of ERβ （P〈0.01） and an increased expression of ERa. Conclusions ERα and ERβ may play important roles in the development of prostate cancer. The decrease in ERβ expression is associated with higher Gleason grade tumours and prostate cancer with higher metastatic potential. The loss of ERβ could be one of the key processes leading to uncontrolled growth of prostate epithelial cells.
文摘Objective:To investigate the potential of N-acetylcysteine(NAC)and zinc sulphate(ZnSO_(4))in mitigating reproductive dysfunction caused by di-2-ethylhexyl phthalate(DEHP)in rats and to understand the underlying mechanisms,specifically oxidative stress and sex hormone receptor activity.Methods:Thirty-five male Wistar rats were randomly divided into five equal groups(n=7 per group).Group 1 was administered 0.5 mL of distilled water and served as the control group.Group 2 was given only DEHP(750 mg/kg/day),while group 3,4 and 5 were given DEHP(750 mg/kg/day)plus NAC(100 mg/kg/day),DEHP(750 mg/kg/day)plus ZnSO_(4)(0.5 mg/kg/day),and DEHP(750 mg/kg/day)plus NAC(100 mg/kg/day)as well as ZnSO_(4)(0.5 mg/kg/day),respectively.All treatments lasted for 21 days.Samples were obtained after the rats were sacrificed,and hormones levels in the serum and markers of oxidative stress in the testicles were analyzed using the enzyme-linked immunosorbent assay.The amount of androgen receptors in the testicles was determined by immunohistochemistry,and the susceptibility of testosterone and DEHP to bind to androgen receptor and 5α-reductase was determined by molecular docking studies.Results:DEHP decreased reproductive hormones,testicular antioxidant enzymes,increased malondialdehyde levels,and negatively impacted histology of the pituitary and testes.NAC or ZnSO_(4) treatment showed a marked improvement in testicular antioxidant status and hormone levels,as well as a positive effect on the histology of the pituitary and testes.The combination of both treatments appeared to be more effective.The affinity of DEHP to bind to androgen receptors may lead to disruption of androgen receptor signaling,which can further result in dysfunction of hormones related to androgen.However,NAC is more likely to form stronger binding interactions with follicle stimulating hormone and luteinizing hormone receptors,as well as gonadotropin-releasing hormone receptors,when compared to DEHP.Conclusions:The possibility that NAC and ZnSO_(4) could downregulate DEHP-induced sex hormone changes is suggested by their potential to reduce toxicity.
