title: [Influence of age and gender on plasma norepinephrine changes produced by orthostatic stress].
abstract: The aim of this work was to determine the effect of aging and gender on plasma norepinephrine (NE) response to orthostatic stress. Fifty-six men and sixty women non-smokers, sedentary, non-obese, were studied at supine and standing positions. On the basis of the age of the subjects, they were divided into three groups of either men or women. Group A, young, range 17-34 years, Group B, middle-age, range 40-60 years, and Group C: senescent, range 61-91 years. Senescent subjects had the highest absolute supine values of NE and significant differences between women and men were found in groups B Men: 298 +/- 15 pg/mL; Women: 348 +/- 14 pg/mL), and C (M: 386 +/- 29 pg/mL; W: 473 +/- 19 pg/mL), but not between young (M: 246 +/- 21 pg/mL; W: 261 +/- 18 pg/mL). NE increased markedly in response to the orthostatic stress but the relative (percentage) increases were smaller in the older subjects perhaps related to their elevated baseline levels. The highest percent positive variation was observed in group A (M: 85%; W: 82%). The oldest group (C), had the lowest variation (M: 23%; W: 21%). The relative increases in NE responses were not different in men and women. The orthostatic-induced variation in NE was negatively related to aging in both men and women (M: r = -0.654; p < 0.0001; W: r = -0.557; p < 0.0001). It is concluded that orthostatic stress induced rise of blood NE is attenuated by age but does not appear to be dependent on gender.
authors.affiliation: Laboratorio de Neuroendocrinología y Reproducción, Dpto. de Fisiopatología, Facultad de Medicina, Universidad de los Andes, Mérida-Venezuela. arabella@telcel.net.com.ve
authors.forename: G
authors.initials: G
authors.lastname: Arata de Bellabarba
authors.forename: C
authors.initials: C
authors.lastname: Molina
authors.forename: D
authors.initials: D
authors.lastname: Dávila Spinetti
authors.forename: V
authors.initials: V
authors.lastname: Villarroel
authors.forename: S A
authors.initials: SA
authors.lastname: Bellabarba
authors.forename: A
authors.initials: A
authors.lastname: Torres
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood*; D011187:Posture / Q000502:physiology*; D012737:Sex Factors; D013312:Stress, Physiological / Q000097:blood*
chemical_list: D009638:Norepinephrine
vernacular_title: Influencia de la edad y el sexo sobre los cambios de norepinefrina plasmática producidos por el stress ortostático.