Androgen receptor CAG and GGN repeat polymorphisms influence performance in boys and girls.

BACKGROUND: Shorter CAG and GGN androgen receptor (AR) repeat polymorphisms are associated with stronger androgen signaling, and therefore, could influence lean mass and exercise performance during growth. METHODS: Physical fitness and body composition were measured by standardized procedures and the length of CAG and GGN repeats was determined by PCR and fragment analysis in 152 boys (11.5±2.6 years; Tanner ≤5) and 116 girls (10.1±3.2 years; Tanner ≤5). Individuals were grouped as CAG short (CAGS) if harboring repeat lengths of ≤21 and CAG long (CAGL) if CAG >21. Moreover, subjects were grouped as GGN short (GGNS) if harboring repeat lengths of ≤23 and GGN long (GGNL) if GGN>23. RESULTS: No significant differences in anthropometrics and body composition were observed between either CAGS and CAGL groups and GGNS and GGNL groups. Boys harboring CAGS completed the 300-meter test faster than their CAGL counterparts. Moreover, girls from the GGNL group showed a significant higher VO2max than those in the GGNS group. CONCLUSIONS: In summary, carrying a short allele of the androgen receptor CAG repeat polymorphism is associated to higher anaerobic performance in boys, whereas long alleles of androgen receptor GGN polymorphisms are associated to higher aerobic capacity in girls.

ANDROGEN RECEPTOR CAG AND GGN REPEAT POLYMORPHISMS AND BONE MASS IN BOYS AND GIRLS.

INTRODUCTION: the human androgen receptor (AR) gene possesses two trinucleotide polymorphic repeats, (CAG and GGN) that affect the amount of AR protein translated. In this study, we genotyped these polymorphic tracts in a representative sample of Caucasian children (Tanner ≤ 5), 152 boys (11.5 } 2.6 yrs) and 116 girls (10.1 } 3.2 yrs) from Spain and investigated their association with bone mass. METHODS: the length of CAG and GGN repeats was determined by PCR and fragment analysis. Body composition was assessed by dual energy x-ray absorptiometry (DXA). Individuals were grouped as CAG short (CAGS) if harboring repeat lengths of ≤ 21 and CAG long (CAGL) if CAG > 21. Moreover, subjects were grouped as GGN short (GGNS) if harboring repeat lengths of ≤ 23 and GGN long (GGNL) if GGN > 23. RESULTS: in boys, significant differences in height, body mass, whole body bone mineral density (BMD) and content (BMC), upper extremities BMC, lower extremities BMC, femoral neck BMD, Ward's triangle BMC and BMD and lumbar spine BMD were observed between CAGS and CAGL groups (P < 0.05). Thus, upper extremities BMD differed between GGNS and GGNL groups. After adjusting for confounding variables, only upper extremities BMD between GGNS and GGNL groups remained significant (P < 0.05). No differences were observed in girls in any measured site in relation to either CAG or GGN polymorphisms length. CONCLUSIONS: our results support the hypothesis that longer alleles of the AR CAG and GGN polymorphisms are associated with increased bone mass in prepubertal boys.

Introducción: el gen humano del receptor de androgenos (AR) posee dos repeticiones polimorficas de trinucleotidos (CAG y GGN) que afectan a la cantidad de proteina AR traducida. En este estudio, genotipamos esos tractos polimorficos en una muestra representativa de ninos caucasicos espanoles (Tanner ≤ 5), compuesta por 152 ninos (11.5 } 2.6 anos) y 116 ninas (10.1 } 3.2 anos) e investigamos su asociacion con la masa osea. Métodos: la longitud de las repeticiones CAG y GGN se determino mediante PCR y analisis de fragmentos. La composicion corporal se midio mediante absorciometria dual de rayos X (DXA). Los participantes fueron agrupados como CAG cortos (CAGS) si poseian una longitud de repeticiones ≤ 21 y CAG largos si esta era > 21. Ademas, los participantes se agruparon como GGN cortos (GGNS) si poseian una longitud de repeticiones ≤ 23 y GGN largos (GGNL) si esta era > 23. Resultados: en los ninos se encontraron diferencias en talla, peso corporal, densidad mineral osea (BMD) y contenido mineral oseo (BMC) del cuerpo entero, BMC de las extremidades superiores e inferiores, BMD del cuello del femur, BMC y BMD del triangulo de Ward's y BMD de la espina lumbar entre los grupos CAGS y CAGL (P < 0,05). Ademas, el BMD de las extremidades superiores fue significativamente diferente entre los grupos GGNS y GGNL. Tras ajustar por variables confusoras, la unica diferencia que se mantuvo significativa fue la del BMD en las extremidades superiores entre los grupos GGNS y GGNL (P < 0,05). No se observaron diferencias entre los grupos CAG y GGN y la masa osea en las ninas. Conclusiones: nuestros resultados apoyan la hipotesis de que los alelos largos de los polimorfismos CAG y GGN del AR estan asociados con una mayor masa osea en ninos prepuberes.

Androgen receptor CAG and GGN repeat polymorphisms and bone mass in boys and girls / Polimorfismos CAG y GGN del gen del receptor de andrógenos y masa ósea en niños y niñas

Introduction: the human androgen receptor (AR) gene possesses two trinucleotide polymorphic repeats, (CAG and GGN) that affect the amount of AR protein translated. In this study, we genotyped these polymorphic tracts in a representative sample of Caucasian children (Tanner ≤5), 152 boys (11.5±2.6 yrs) and 116 girls (10.1±3.2 yrs) from Spain and investigated their association with bone mass. Methods: the length of CAG and GGN repeats was determined by PCR and fragment analysis. Body composition was assessed by dual energy x-ray absorptiometry (DXA). Individuals were grouped as CAG short (CAGS) if harboring repeat lengths of ≤21 and CAG long (CAGL) if CAG >21. Moreover, subjects were grouped as GGN short (GGNS) if harboring repeat lengths of ≤23 and GGN long (GGNL) if GGN >23. Results: in boys, significant differences in height, body mass, whole body bone mineral density (BMD) and content (BMC), upper extremities BMC, lower extremities BMC, femoral neck BMD, Ward’s triangle BMC and BMD and lumbar spine BMD were observed between CAGS and CAGL groups (P<0.05). Thus, upper extremities BMD differed between GGNS and GGNL groups. After adjusting for confounding variables, only upper extremities BMD between GGNS and GGNL groups remained significant (P<0.05). No differences were observed in girls in any measured site in relation to either CAG or GGN polymorphisms length. Conclusions: our results support the hypothesis that longer alleles of the AR CAG and GGN polymorphisms are associated with increased bone mass in prepubertal boys (AU)

Introducción: el gen humano del receptor de andrógenos (AR) posee dos repeticiones polimórficas de trinucleótidos (CAG y GGN) que afectan a la cantidad de proteína AR traducida. En este estudio, genotipamos esos tractos polimórficos en una muestra representativa de niños caucásicos españoles (Tanner ≤5), compuesta por 152 niños (11.5±2.6 años) y 116 niñas (10.1±3.2 años) e investigamos su asociación con la masa ósea. Métodos: la longitud de las repeticiones CAG y GGN se determinó mediante PCR y análisis de fragmentos. La composición corporal se midió mediante absorciometría dual de rayos X (DXA). Los participantes fueron agrupados como CAG cortos (CAGS) si poseían una longitud de repeticiones ≤21 y CAG largos si esta era >21. Además, los participantes se agruparon como GGN cortos (GGNS) si poseían una longitud de repeticiones ≤23 y GGN largos (GGNL) si esta era >23. Resultados: en los niños se encontraron diferencias en talla, peso corporal, densidad mineral ósea (BMD) y contenido mineral óseo (BMC) del cuerpo entero, BMC de las extremidades superiores e inferiores, BMD del cuello del fémur, BMC y BMD del triángulo de Ward’s y BMD de la espina lumbar entre los grupos CAGS y CAGL (P<0,05). Además, el BMD de las extremidades superiores fue significativamente diferente entre los grupos GGNS y GGNL. Tras ajustar por variables confusoras, la única diferencia que se mantuvo significativa fue la del BMD en las extremidades superiores entre los grupos GGNS y GGNL (P<0,05). No se observaron diferencias entre los grupos CAG y GGN y la masa ósea en las niñas. Conclusiones: nuestros resultados apoyan la hipótesis de que los alelos largos de los polimorfismos CAG y GGN del AR están asociados con una mayor masa ósea en niños prepúberes (AU)

Transition to androgen-independence in prostate cancer.

Prostate carcinoma is the most frequently diagnosed malignancy and the second leading cause of death as a result of cancer in men in the western countries. Withdrawal of androgens or the peripheral blockage of androgen action remain the critical therapeutic options for the treatment of advanced prostate cancer. However, after initial regression, most of the prostate cancers become androgen-independent and progress further, with eventual fatal outcome. Understanding the mechanisms of transition to androgen independence and tumor progression in prostate cancer is critical to finding new ways to treat aged patients that are ineligible for conventional chemotherapy. A large number of different molecular mechanisms might be responsible for the transition to androgen-independence. Many of these involve the androgen receptor (AR) and its signalling pathways, but they might also include genetic changes that affect several genes, which results in the activation of oncogenes or the inactivation of tumor suppressor genes. Here, we discuss the most recent and relevant findings on androgen resistance in prostate cancer in order provide a comprehensive interpretation of the clinical behaviour of tumors at molecular levels.

Evaluation of acute hepatotoxic effects exerted by environmental estrogens nonylphenol and 4-octylphenol in immature male rats.

Nonylphenol (NP) and 4-Octylphenol (4OP) have shown estrogenic properties both in vivo and in vitro. Researchers have known for years that estrogens induce a wide number of hepatotoxic actions in rodents. In order to study the acute hepatic effects exerted by NP and 4OP on rat liver the following endpoints were evaluated: relative liver weight (RLW), morphology, cell cycle and ploidy status, monooxygenase enzymes content and levels of both, cytosolic estrogen receptor (cER) and microsomal binding sites for estrogens (mEBS). Immature male Sprague-Dawley rats were injected intraperitoneally (i.p.) with 60 mg/kg of NP or 4OP for 1, 5 or 10 days. Despite the fact that RLW of the animals was not modified but any treatment, the histopathological study revealed the presence of an increase in the percentage of both, mitotic activity and Ki-67-labeling index (LI) in the livers from animals treated with alkylphenols in absence of any degenerative lesion. Furthermore, all the livers from alkylphenols-treated groups showed the presence of abnormal mitosis and c-mitosis. Although the levels of both, cER and cytochrome P450 (Cyt. P450) were not affected by any treatment, concentration of the mEBS was decreased after 10 days of treatment with alkylphenols. These findings taken together suggest that the exposition to alkylphenols induce cell proliferation and spindle disturbances and that these compounds are capable of modulating the expression of putative membrane receptors for estrogens.

Steroid hormone progesterone induces cell proliferation and abnormal mitotic processes in rat liver.

The aim of this study was to evaluate the acute hepatic effects exerted by the steroid hormone progesterone (PR) in the rat. Although the liver is not a target tissue for this hormone, a number of hepatic actions of PR have been described, and, furthermore, a specific binding site for PR (PBS) exists in rat liver microsomes. Immature male rats were treated intraperitoneally with 60 mg/kg PR per day for 1, 5 or 10 days, and different parameters were evaluated in order to detect possible alterations in liver cells. Morphological study of the livers did not present images of cytotoxicity in any group of animals. The presence of a clear hyperplasia of smooth endoplasmic reticulum (SER) was noteworthy, mainly seen in perilobular hepatocytes. Despite this SER increase, the levels of cytochrome P450 (Cyt P450) significantly decreased after 10 days of PR administration. Similarly, the concentration of PBS was significantly decreased after 10 days of treatment with PR. On the other hand, these studies revealed a clear increase of mitotic activity and Ki-67 labelling index in the livers of animals treated with PR; furthermore, livers of PR-treated animals showed an increased percentage of binucleate hepatocytes. Flow cytometry analysis showed that although ploidy status of liver cells was not modified in any case the percentage of diploid nuclei in S-phase decreased during treatment with PR. The most relevant finding was the presence of abnormal mitosis and c-mitosis in livers from animals from all PR-treated groups. This study demonstrates that PR (a) does not induce cytotoxicity although it can induce cell proliferation and spindle disturbances in liver cells, (b) may also modulate the drug-metabolizing liver enzyme function, and (c) downregulates the expression of its own microsomal specific binding site.