The objective of the present study was to investigate the effects of genistein and equol on 3β-hydroxysteroid de- hydrogenase （3β-HSD） and 17β-hydroxysteroid dehydrogenase 3 （17β-HSD3） in human and rat testis ...The objective of the present study was to investigate the effects of genistein and equol on 3β-hydroxysteroid de- hydrogenase （3β-HSD） and 17β-hydroxysteroid dehydrogenase 3 （17β-HSD3） in human and rat testis microsomes. These enzymes （3β-HSD and 17β-HSD3）, along with two others （cytochrome P450 side-chain cleavage enzyme and cytochrome P450 17α-hydroxylase/17-20 lyase）, catalyze the reactions that convert the steroid cholesterol into the sex hormone testosterone. Genistein inhibited 3β-HSD activity （0.2 μmol L^-1 pregnenolone） with half-maximal inhibition or a half-maximal inhibitory concentration （IC50） of 87 ± 15 （human） and 636 ± 155 nmol L^-1 （rat）. Genistein＇s mode of action on 3β-HSD activity was competitive for the substrate pregnenolonrge and noncompetitive for the cofactor NAD＋. There was no difference in genistein＇s potency of 3β-HSD inhibition between intact rat Leydig cells and testis microsomes. In contrast to its potent inhibition of 3β-HSD, genistein had lesser effects on human and rat 17β-HSD3 （0.1 μmol L^-1 androstenedione）, with an IC50 〉 100μmol L^-1. On the other hand, equol only inhibited human 3β-HSD by 42%, and had no effect on 3β-HSD and 17β-HSD3 in rat tissues. These observations imply that the ability of soy isoflavones to regulate androgen biosynthesis in Leydig cells is due in part to action on Leydig cell 3β- HSD activity. Given the increasing intake of soy-based food products and their potential effect on blood androgen levels, these findings are greatly relevant to public health.展开更多
11β-hydroxysteroid dehydrogenase type 1 （11β-HSD1） and type 2 （11β-HSD2） are expressed in rat testis, where they regulate the local concentrations of glucocorticoids. Here, we investigated the expression and lo...11β-hydroxysteroid dehydrogenase type 1 （11β-HSD1） and type 2 （11β-HSD2） are expressed in rat testis, where they regulate the local concentrations of glucocorticoids. Here, we investigated the expression and localization of 11β-HSD in rat testis during postnatal development, and the regulation of these genes by luteinizing hormone （LH） and androgens, mRNA and protein levels were analyzed by quantitative real-time-polymerase chain reaction and western blotting, respectively, in testes collected from rats at postnatal day （PND） 7, 14, 21, 35, and 90, and from rats treated with LH, 7α.methyl-19-nortestosterone （MENT） and testosterone at PND 21 and PND 90. Immunohistochemical staining was used to identify the localization of the 11β-HSD in rat testis at PND 7, 14, and 90. We found that 11β-HSD1 expression was restricted to the interstitial areas, and that its levels increased during rat testis development. In contrast, whereas 11β-HSD2 was expressed in both the interstitial areas and seminiferous tubules at PND 7, it was present only in the interstitial areas at PND 90, and its levels declined during testicular development. Moreover, 11β-HSD1 mRNA was induced by LH in both the PND 21 and 90 testes and by MENT at PND 21, whereas 11β-HSD2 mRNA was induced by testosterone and MENT in the PND 21 testis and by LH in the PND 90 testis. In conclusion, our study indicates that the 11β-HSD1 and 11β-HSD2 genes have distinct patterns of spatiotemporal expression and hormonal regulation during postnatal development of the rat testis.展开更多
Type 2 diabetes mellitus is a metabolic disorder of deranged fat, protein and carbohydrate metabolism resulting in hyperglycemia as a result of insulin resistance and inadequate insulin secretion. Although a wide vari...Type 2 diabetes mellitus is a metabolic disorder of deranged fat, protein and carbohydrate metabolism resulting in hyperglycemia as a result of insulin resistance and inadequate insulin secretion. Although a wide variety of diabetes therapies is available, yet limited efficacy, adverse effects, cost, contraindications, renal dosage adjustments, inflexible dosing schedules and weight gain significantly limit their use. In addition, many patients in the United States fail to meet the therapeutic HbA1c goal of 【 7% set by the American Diabetes Association. As such new and emerging diabetes therapies with different mechanisms of action hope to address some of these drawbacks to improve the patient with type 2 diabetes. This article reviews new and emerging classes, including the sodium-glucosecotransporter-2 inhibitors, 11β-Hydroxysteroid dehydrogenase type 1 inhibitors, glycogen phosphorylase inhibitors; protein tyrosine phosphatase 1B inhibitors, G Protein-Coupled receptor agonists and glucokinase activators. These emerging diabetes agents hold the promise of providing benefit of glucose lowering, weight reduction, low hypoglycemia risk, improve insulin sensitivity, pancreatic β cell preservation, and oral formulation availability. However, further studies are needed to evaluate their safety profile, cardiovascular effects, and efficacy durability in order to determine their role in type 2 diabetes management.展开更多
17β-hydroxysteroid dehydrogenase(17β-HSD)type 1 is known as a critical target to block the final step of estrogen production in estrogen-dependent breast cancer.Recent confirmation of the role of dyhydroxytestostero...17β-hydroxysteroid dehydrogenase(17β-HSD)type 1 is known as a critical target to block the final step of estrogen production in estrogen-dependent breast cancer.Recent confirmation of the role of dyhydroxytestosterone(DHT)in counteracting estrogeninduced cell growth prompted us to study the reductive 17β-HSD type 7(17β-HSD7),which activates estrone while markedly inactivatingDHT.The role ofDHTin breast cancer cell proliferation isdemonstratedby its independent suppression of cell growthin the presence of a physiological concentration of estradiol(E2).Moreover,an integral analysis of a large number of clinical samples in Oncomine datasets demonstrated the overexpression of 17β-HSD7 in breast carcinoma.Inhibition of 17β-HSD7 in breast cancer cells resulted in a lower level of E2 and a higher level of DHT,successively induced regulation of cyclinD1,p21,Bcl-2,and Bik,consequently arrested cell cycle in the G0/G1 phase,and triggered apoptosis and auto-downregulation feedback of the enzyme.Such inhibition led to significant shrinkage of xenograft tumors with decreased cancer cell density and reduced 17β-HSD7 expression.Decreased plasma E2 and elevated plasma DHT levels were also found.Thus,the dual functional 17β-HSD7 is proposed as a novel target for estrogen-dependent breast cancer by regulating the balance of E2 andDHT.Thisdemonstrates aconceptual advance on the general belief that the major role of this enzyme is in cholesterol metabolism.展开更多
Endometriosis is a common benign gynecological disorder with an enigmatic etiology and pathogenesis.It affects approximately 10%women of reproductive age.Although its etiology and pathogenesis remain poorly understood...Endometriosis is a common benign gynecological disorder with an enigmatic etiology and pathogenesis.It affects approximately 10%women of reproductive age.Although its etiology and pathogenesis remain poorly understood,it is characterized by the elevated local production of estrogen in the endometriotic tissues.In this paper,we review the mechanisms of estrogen biosynthesis and its regulation in endometriosis.展开更多
文摘The objective of the present study was to investigate the effects of genistein and equol on 3β-hydroxysteroid de- hydrogenase （3β-HSD） and 17β-hydroxysteroid dehydrogenase 3 （17β-HSD3） in human and rat testis microsomes. These enzymes （3β-HSD and 17β-HSD3）, along with two others （cytochrome P450 side-chain cleavage enzyme and cytochrome P450 17α-hydroxylase/17-20 lyase）, catalyze the reactions that convert the steroid cholesterol into the sex hormone testosterone. Genistein inhibited 3β-HSD activity （0.2 μmol L^-1 pregnenolone） with half-maximal inhibition or a half-maximal inhibitory concentration （IC50） of 87 ± 15 （human） and 636 ± 155 nmol L^-1 （rat）. Genistein＇s mode of action on 3β-HSD activity was competitive for the substrate pregnenolonrge and noncompetitive for the cofactor NAD＋. There was no difference in genistein＇s potency of 3β-HSD inhibition between intact rat Leydig cells and testis microsomes. In contrast to its potent inhibition of 3β-HSD, genistein had lesser effects on human and rat 17β-HSD3 （0.1 μmol L^-1 androstenedione）, with an IC50 〉 100μmol L^-1. On the other hand, equol only inhibited human 3β-HSD by 42%, and had no effect on 3β-HSD and 17β-HSD3 in rat tissues. These observations imply that the ability of soy isoflavones to regulate androgen biosynthesis in Leydig cells is due in part to action on Leydig cell 3β- HSD activity. Given the increasing intake of soy-based food products and their potential effect on blood androgen levels, these findings are greatly relevant to public health.
文摘11β-hydroxysteroid dehydrogenase type 1 （11β-HSD1） and type 2 （11β-HSD2） are expressed in rat testis, where they regulate the local concentrations of glucocorticoids. Here, we investigated the expression and localization of 11β-HSD in rat testis during postnatal development, and the regulation of these genes by luteinizing hormone （LH） and androgens, mRNA and protein levels were analyzed by quantitative real-time-polymerase chain reaction and western blotting, respectively, in testes collected from rats at postnatal day （PND） 7, 14, 21, 35, and 90, and from rats treated with LH, 7α.methyl-19-nortestosterone （MENT） and testosterone at PND 21 and PND 90. Immunohistochemical staining was used to identify the localization of the 11β-HSD in rat testis at PND 7, 14, and 90. We found that 11β-HSD1 expression was restricted to the interstitial areas, and that its levels increased during rat testis development. In contrast, whereas 11β-HSD2 was expressed in both the interstitial areas and seminiferous tubules at PND 7, it was present only in the interstitial areas at PND 90, and its levels declined during testicular development. Moreover, 11β-HSD1 mRNA was induced by LH in both the PND 21 and 90 testes and by MENT at PND 21, whereas 11β-HSD2 mRNA was induced by testosterone and MENT in the PND 21 testis and by LH in the PND 90 testis. In conclusion, our study indicates that the 11β-HSD1 and 11β-HSD2 genes have distinct patterns of spatiotemporal expression and hormonal regulation during postnatal development of the rat testis.
文摘Type 2 diabetes mellitus is a metabolic disorder of deranged fat, protein and carbohydrate metabolism resulting in hyperglycemia as a result of insulin resistance and inadequate insulin secretion. Although a wide variety of diabetes therapies is available, yet limited efficacy, adverse effects, cost, contraindications, renal dosage adjustments, inflexible dosing schedules and weight gain significantly limit their use. In addition, many patients in the United States fail to meet the therapeutic HbA1c goal of 【 7% set by the American Diabetes Association. As such new and emerging diabetes therapies with different mechanisms of action hope to address some of these drawbacks to improve the patient with type 2 diabetes. This article reviews new and emerging classes, including the sodium-glucosecotransporter-2 inhibitors, 11β-Hydroxysteroid dehydrogenase type 1 inhibitors, glycogen phosphorylase inhibitors; protein tyrosine phosphatase 1B inhibitors, G Protein-Coupled receptor agonists and glucokinase activators. These emerging diabetes agents hold the promise of providing benefit of glucose lowering, weight reduction, low hypoglycemia risk, improve insulin sensitivity, pancreatic β cell preservation, and oral formulation availability. However, further studies are needed to evaluate their safety profile, cardiovascular effects, and efficacy durability in order to determine their role in type 2 diabetes management.
基金supported by operating grants from Canadian Institutes of Health Research(CIHR,MOP 97917 to S.-X.L.,D.P.,and C.J.D.MOP 89851 to S.-X.L.and D.P.)China Scholarship Council(PhD Fellowship,#2010621032 to X.Q.W.).
文摘17β-hydroxysteroid dehydrogenase(17β-HSD)type 1 is known as a critical target to block the final step of estrogen production in estrogen-dependent breast cancer.Recent confirmation of the role of dyhydroxytestosterone(DHT)in counteracting estrogeninduced cell growth prompted us to study the reductive 17β-HSD type 7(17β-HSD7),which activates estrone while markedly inactivatingDHT.The role ofDHTin breast cancer cell proliferation isdemonstratedby its independent suppression of cell growthin the presence of a physiological concentration of estradiol(E2).Moreover,an integral analysis of a large number of clinical samples in Oncomine datasets demonstrated the overexpression of 17β-HSD7 in breast carcinoma.Inhibition of 17β-HSD7 in breast cancer cells resulted in a lower level of E2 and a higher level of DHT,successively induced regulation of cyclinD1,p21,Bcl-2,and Bik,consequently arrested cell cycle in the G0/G1 phase,and triggered apoptosis and auto-downregulation feedback of the enzyme.Such inhibition led to significant shrinkage of xenograft tumors with decreased cancer cell density and reduced 17β-HSD7 expression.Decreased plasma E2 and elevated plasma DHT levels were also found.Thus,the dual functional 17β-HSD7 is proposed as a novel target for estrogen-dependent breast cancer by regulating the balance of E2 andDHT.Thisdemonstrates aconceptual advance on the general belief that the major role of this enzyme is in cholesterol metabolism.
基金supported in part by grants 81471434(SWG),81530040(SWG),81370695(XSL),and 81671436(XSL)the National Natural Science Foundation of China.
文摘Endometriosis is a common benign gynecological disorder with an enigmatic etiology and pathogenesis.It affects approximately 10%women of reproductive age.Although its etiology and pathogenesis remain poorly understood,it is characterized by the elevated local production of estrogen in the endometriotic tissues.In this paper,we review the mechanisms of estrogen biosynthesis and its regulation in endometriosis.
