Project description:Androgenic steroids are increasingly used for hormone therapy of postmenopausal women and abused as life style drugs and for doping purposes, though knowledge about associated health risks in females is very limited. In order to understand more about short- and long-term androgen effects on a molecular level, we have analyzed hepatic gene expression in female C57BL/6 mice immediately after subcutaneous treatment with testosterone for 3 weeks and after 12 weeks hormone withdrawal using Affymetrix array technology and quantitative real-time RT-PCR. Among about 14,000 genes examined, 48 were up- and 65 genes were downregulated by testosterone after 3-weeks treatment and about 50% of these changes persisted even 12 weeks after testostrone withdrawal. In addition to obvious risks such as induction of hepatocellular carcinomas and virilization of liver metabolism, testosterone induced a series of changes, as e.g. dysregulation of hepatic gene expression due to incomplete conversion of female to male phenotype â in particular downregulation of cytochrom P450 isoforms and sulfotransferases. As a long-term testosterone effect, transcripts emerged in the liver that are normally specific for the exocine pancreas including amylase 2, ribonuclease 1, and several trypsin-, chymotrypsin-, and elastase-like proteases. This transdifferentiation of hepatic to exocrine pancreatic tissue indicates that testosterone can initiate long-lasting differentiation programs, which â once induced â progress even after androgen withdrawal. This may have far-reaching consequences difficult to foresee implying long-term hazards of testosterone-treatment for female health that have not been taken into account yet. Mice were treated with testosterone or sesame oil (vehicle) for three weeks twice a week. Gene expression in the liver was analyzed either directly after treatment or after three weeks of hormone/vehicle withdrawal. For each of these four groups, three individual mice were used as biological replicates.

Project description:Population based studies have established that androgen deficiency in males correlates with type 2 diabetes, visceral adiposity, and metabolic syndrome. Androgen therapy has been investigated as a possible treatment regime to combat these disorders. However, the molecular mechanism of androgen effects on these diseases still remain poorly understood. The zucker diabetic fatty (ZDF) rat, containing a mutation in the leptin receptor, is a well-investigated model of obesity and type 2 diabetes. Male rats are characterized as androgen deficient and spontaneously develop obese, hyperlipidemia, hyperglycemia and hyperinsulinemia. In this study, we used ZDF male rats as a model of metabolic syndrome to investigate the effects of testosterone administration on the development of the metabolic conditions. Methods: Male ZDF rats at six week of age were randomly divided into two groups and administered testosterone undecanoate(TU) or vehicle alone every three days for three weeks. After three weeks, overnight fasted blood glucose and insulin concentrations were significantly higher and glucose tolerance and insulin sensitivity were impaired in TU treated ZDF rats compared to vehicle controls. Moreover, increased serum triglycerides and VLDL were observed in TU treated rats. To further explore the observed metabolic changes in TU treated ZDF rats, whole-genome microarray analysis were performed on isolated liver mRNA. Results: Array analysis revealed that many hepatic lipogenic genes were increased in male ZDF rat livers treated with TU. Interestingly, SREBP-1c, a key transcriptional activator of lipogenic genes and PGC-1 , an activator of SREBP-1c were induced while small heterodimer partner, a transcriptional inhibitor of lipogenic genes was suppressed by TU treatment. Exploring signaling pathways for these effects, we observed that the hepatic activated forms of STAT3 and AMPK, two known inhibitors of hepatic lipogenesis, were decreased in TU treated rat. Moreover, we observed that DHT could block the induction of STAT3 and AMPK phosphorylation in treated primary human hepatocytes. Preliminarily, in the leptin receptor positive zucker diabetic lean male rats, we observed that TU treatment has an oppose effect on the hepatic lipogenic genes, suggesting that hepatic leptin signaling may influence androgen signaling. Further insight into the relationship between androgen deficiency and the leptin system may help improve treatment of the metabolic syndrome. Population based studies have established that androgen deficiency in males correlates with type 2 diabetes, visceral adiposity, and metabolic syndrome. Androgen therapy has been investigated as a possible treatment regime to combat these disorders. However, the molecular mechanism of androgen effects on these diseases still remain poorly understood. The zucker diabetic fatty (ZDF) rat, containing a mutation in the leptin receptor, is a well-investigated model of obesity and type 2 diabetes. Male rats are characterized as androgen deficient and spontaneously develop obese, hyperlipidemia, hyperglycemia and hyperinsulinemia. In this study, we used ZDF male rats as a model of metabolic syndrome to investigate the effects of testosterone administration on the development of the metabolic conditions. Two-condition experiment. (1) lean ZDF rats (control) vs. lean ZDF rats (testosterone treated). (2) obese ZDF rats (control) vs. obese ZDF rats (testosterone treated). Biological replicates: 4 control replicates, 4 treated replicates.

Project description:Population based studies have established that androgen deficiency in males correlates with type 2 diabetes, visceral adiposity, and metabolic syndrome. Androgen therapy has been investigated as a possible treatment regime to combat these disorders. However, the molecular mechanism of androgen effects on these diseases still remain poorly understood. The zucker diabetic fatty (ZDF) rat, containing a mutation in the leptin receptor, is a well-investigated model of obesity and type 2 diabetes. Male rats are characterized as androgen deficient and spontaneously develop obese, hyperlipidemia, hyperglycemia and hyperinsulinemia. In this study, we used ZDF male rats as a model of metabolic syndrome to investigate the effects of testosterone administration on the development of the metabolic conditions. Methods: Male ZDF rats at six week of age were randomly divided into two groups and administered testosterone undecanoate(TU) or vehicle alone every three days for three weeks. After three weeks, overnight fasted blood glucose and insulin concentrations were significantly higher and glucose tolerance and insulin sensitivity were impaired in TU treated ZDF rats compared to vehicle controls. Moreover, increased serum triglycerides and VLDL were observed in TU treated rats. To further explore the observed metabolic changes in TU treated ZDF rats, whole-genome microarray analysis were performed on isolated liver mRNA. Results: Array analysis revealed that many hepatic lipogenic genes were increased in male ZDF rat livers treated with TU. Interestingly, SREBP-1c, a key transcriptional activator of lipogenic genes and PGC-1 , an activator of SREBP-1c were induced while small heterodimer partner, a transcriptional inhibitor of lipogenic genes was suppressed by TU treatment. Exploring signaling pathways for these effects, we observed that the hepatic activated forms of STAT3 and AMPK, two known inhibitors of hepatic lipogenesis, were decreased in TU treated rat. Moreover, we observed that DHT could block the induction of STAT3 and AMPK phosphorylation in treated primary human hepatocytes. Preliminarily, in the leptin receptor positive zucker diabetic lean male rats, we observed that TU treatment has an oppose effect on the hepatic lipogenic genes, suggesting that hepatic leptin signaling may influence androgen signaling. Further insight into the relationship between androgen deficiency and the leptin system may help improve treatment of the metabolic syndrome. Population based studies have established that androgen deficiency in males correlates with type 2 diabetes, visceral adiposity, and metabolic syndrome. Androgen therapy has been investigated as a possible treatment regime to combat these disorders. However, the molecular mechanism of androgen effects on these diseases still remain poorly understood. The zucker diabetic fatty (ZDF) rat, containing a mutation in the leptin receptor, is a well-investigated model of obesity and type 2 diabetes. Male rats are characterized as androgen deficient and spontaneously develop obese, hyperlipidemia, hyperglycemia and hyperinsulinemia. In this study, we used ZDF male rats as a model of metabolic syndrome to investigate the effects of testosterone administration on the development of the metabolic conditions.

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Testosterone-induced persistent dysregulations and transdifferentiation to exocrine pancreas in the female liver

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