Las hormonas femeninas en fisiología renal: Sensibilidad a la sal y regulación de la proliferación epitelial / Female hormones in renal physiology. Salt sensitivity and regulation of epithelial proliferation

Un tercio de la población mundial tiene niveles anormalmente altos de presión arterial, hipertensión, responsable de casi el 50% de las muertes por accidente cerebrovascular y enfermedad coronaria. La sensibilidad a la sal es un factor de riesgo para la morbilidad y mortalidad cardiovascular y también para otras enfermedades. En estudios previos describimos un modelo de hipertensión sal sensible (HSS) en ratas Wistar ovariectomizadas (oVx) adultas. Las ratas oVx son normotensas con ingesta normal de sal (NS, 0.24% de NaCl), pero desarrollan un perfil de HSS con una ingesta elevada de sal (HS, 1% de NaCl). En los estudios en riñón encontramos que el circuito receptor D1 de dopamina, citocromo P450 4A y Na+, K+-ATPasa está alterado por la ausencia de hormonas ováricas, lo que se asocia a menor excreción de sodio e hipertensión arterial. La ingesta HS en ratas oVx también promueve cambios en la expresión de proteínas relacionadas con el transporte de sodio en células mononucleares de sangre periférica, principalmente linfocitos periféricos. Por lo tanto, el transporte de sodio se modifica en varios niveles de la fisiología normal. En estudios recientes observamos que el estradiol aumenta la proliferación y diferenciación de células epiteliales en cultivos de corteza renal humana. Sensibilidad a la sal, inmunidad adaptativa, presión arterial y proliferación de células epiteliales en riñón son fenómenos de gran importancia biológica regulados por estradiol.

Female sex hormones participate in the regulation of blood pressure and renal epithelial proliferation, effects not related to their reproductive function. About one-third of the world's population has abnormally high levels of blood pressure, hypertension, which is responsible for almost 50% of deaths from stroke and coronary heart disease. Salt sensitivity is a risk factor for cardiovascular morbidity and mortality and other diseases as well. We reported a model of salt sensitive hypertension in adult ovariectomized (oVx) Wistar rats. oVx rats are normotensive under normal salt intake (NS, 0.24% NaCl), but upon a high salt intake (HS, 1% NaCl) oVx rats developed a blood pressure profile of salt-sensitive hypertension. Our studies on kidney molecules related to sodium balance found that the circuit dopamine D1-like receptor, cytochrome P450 4A and Na+, K+-ATPase is altered by the absence of ovary hormones which is accompanied by a reduced ability to excrete sodium. In oVx rats HS intake also promotes changes in the expression of proteins related to sodium transport in peripheral blood mononuclear cells, mainly peripheral lymphocytes. Therefore, sodium transport is modified at several levels of normal physiology. Lately, we described that estradiol increases the rate of renal epithelial cell proliferation in primary cultures developed from human renal cortex. Thus, salt sensitivity, adaptive immunity, blood pressure and renal cell proliferation are complex biological responses regulated by female sex hormones.

Female Hormone Factors Associated with Age-related Macular Degeneration in Menopausal Korean Women: KNHANES V

PURPOSE: To investigate whether endogenous and exogenous female hormone exposures were associated with risks for age-related macular degeneration (AMD) in postmenopausal women. METHODS: This study included 4,479 postmenopausal females aged 45 years and older who completed the Korea National Health and Nutrition Examination Survey (KNHANES) V. The participants were divided into 4 groups: subjects with AMD, subjects without AMD, subjects with early AMD, and subjects with late AMD. Variables associated with endogenous and exogenous female hormone exposures were analyzed. RESULTS: Among the 4,479 participants, 516 were found to have AMD and 3,963 were normal. There was no significant difference between the AMD and normal groups execpt for age in the risk analysis. Of the total 516 AMD participants, 488 had early AMD and 28 had late AMD. Women with AMD who had used oral contraceptives longer in the past had significantly higher odds of late AMD than early AMD (odds ratio [OR] = 1.013, 95% confidence interval [CI]: 1.002–1.024). Increasing number of children was also associated with decreased odds of late AMD (OR = 0.672, 95% CI: 0.506-0.893). CONCLUSIONS: These findings suggest that exposure to endogenous and exogenous female hormones may influence the risk of AMD progression.

Effects of Female Hormones and Menstrual Cycle on Female Relaxed G-Tolerance / 항공우주의학회지

BACKGROUND: With increasing number of female pilots who fly high-performance aircraft, the gender specific factors have become one of the most important aeromedical considerations. It has been raised that the changes of serum female hormone levels by menstrual cycle may affect vasoregulation and female G-tolerance ultimately. However, the exact relationship between serum female hormone levels and G-tolerance is still unknown. Moreover, well-controlled subjects without taking oral contraceptives are needed to examine the possible effect of menstrual cycle on female G-tolerance. The purpose of this study was to determine how female hormones and menstrual cycle affect female relaxed G-tolerance. METHODS: Eight female subjects were studied to test their relaxed G-tolerance. Seven out of 8 subjects had regular menstrual cycle during the study period. Each subject were exposed to human centrifuge once a week for 4 weeks (one complete menstrual cycle) and blood samplings were performed twice at 2nd and 4th week just before exposure to human centrifuge. The profile of centrifuge training consisted of gradual-onset run (0.1 G/sec) acceleration to the visual endpoint. RESULTS: The changes of 4 different serum female hormone levels failed to show any trend related to relaxed G-tolerance including estrogen. There was no significant difference in relaxed G-tolerance in any menstrual cycle time points. CONCLUSION: We conclude that the changes of female hormone levels and the menstrual cycle have no effect on female relaxed G-tolerance.

Variation in Maximal Voluntary Contraction During the Menstrual Cycle / 体力科学

The purpose of this study was to determine the change in elbow flexor isometric torque at different phases of the menstrual cycle in humans. The subjects were six eumenorrheic females (age 22.0±3.5yr ; height 156.5±3.3cm ; body mass 50.2±4.9 kg) . The serum luteinizing hormone (LH), estradiol and progesterone levels, maximal voluntary contraction (MVC), integrated electromyographic activity (iEMG), interpolated twitch torque, evoked contractile properties, anthropometric parameters and Profile of Mood States (POMS) were measured at three different phases of the menstrual cycle, i. e., the menstrual, ovulatory and luteal phases. The MVC was significantly higher in the ovulatory phase than in the menstrual and luteal phases (P<0.05) . The iEMG, calculated voluntary activation and anthropometric parameters did not change significantly over the menstrual cycle. The MVC/iEMG ratio (electromechanical efficiency) and the evoked peak torque were also significantly higher in the ovulatory phase than in the menstrual and luteal phases (P<0.05, P<0.01) . In the menstrual phase, the fatigue and anger subscale score of POMS were significantly higher (P<0.05) and the vigor subscale score was significantly lower than in the other phases (P<0.05) . These results indicate that the variation in MVC observed over the menstrual cycle may be related to the intrinsic contractile properties rather than neural or psychological factors.