RESUMEN
CONTEXT: The gonads are the major source of sex steroids during reproductive ages. The gonadal function declines abruptly in women and gradually in men. The adrenals produce 11-oxygenated androgens (11-oxyandrogens), which start rising during adrenarche. Following menopause, 11-oxyandrogens levels remain similar to reproductive ages. OBJECTIVE: To compare the circulating 11-oxyandrogen concentrations in men and women across adult ages. METHODS: We used mass spectrometry to measure testosterone (T), androstenedione (A4), 11ß-hydroxytestosterone (11OHT), 11-ketotestosterone (11KT), 11ß-hydroxyandrostenedione (11OHA4), 11-ketoandrostenedione (11KA4), cortisol, and cortisone in morning sera obtained from adults in outpatient setting. We performed double immunofluorescence of 3ß-hydroxysteroid dehydrogenase type 2 and cytochrome b5 in adrenal tissue from 19 men, age 23-78 years. RESULTS: We included 590 patients (319 men), aged 18 to 97 years, and 84% white. 11KT and 11KA4 were stable across ages in women, but they declined in men (0.21 and 0.06 ng/dL/year, respectively; P < 0.05). 11OHA4 and 11OHT increased modestly with age in women (0.6 and 0.09 ng/dL/year, respectively; P < 0.01), and both remained stable across ages in men. As body mass index (BMI) increased, 11KA4 decreased in women, and 11KT increased in men, both suggesting higher 17ß-hydroxysteroid dehydrogenase activity in obese individuals. A4 and T declined with age and A4 with BMI in both sexes; T declined with BMI in men. Adrenal androgenic enzyme expressions in aging men were similar to those observed in women. CONCLUSIONS: In contrast with traditional androgens, the production of 11OHA4 and 11OHT is sustained with aging in both sexes. The bioactive androgen 11KT declines in aging men but not in women.
Asunto(s)
Envejecimiento/sangre , Andrógenos/sangre , Androstenodiona/análogos & derivados , Hidroxitestosteronas/sangre , Testosterona/análogos & derivados , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Envejecimiento/fisiología , Androstenodiona/sangre , Androstenodiona/fisiología , Estudios de Cohortes , Femenino , Humanos , Masculino , Persona de Mediana Edad , Factores Sexuales , Testosterona/sangre , Testosterona/fisiología , Adulto JovenRESUMEN
Many animals acquire biologically important information from conspecifics. Social learning has been demonstrated in many animals, but there are few experimental paradigms that are suitable for detailed analysis of its associative processes. We established procedures for appetitive and aversive social learning with living and dead conspecifics in well-controlled stimulus arrangements in crickets, Gryllus bimaculatus. A thirsty demonstrator cricket was released in a demonstrator room and allowed to visit two drinking apparatuses that contained water or saltwater and emitted apple or banana odour, and a thirsty learner was allowed to observe the demonstrator room through a net. In the post-training test, the learner preferred the odour of the water-containing apparatus at which the demonstrator stayed. When a dead cricket was placed on one of the two apparatuses, the learner avoided the odour of that apparatus. Further experiments suggested that a living conspecific can be recognized by either visual or olfactory cues for appetitive social learning, whereas olfactory cues are needed to recognize a dead conspecific for aversive social learning, and that different associative processes underlie social learning with living and dead conspecifics. The experimental paradigms described here will pave the way for detailed research on the neural basis of social learning.