RESUMEN
Caspase-3 is the main executor of the apoptotic process. Higher serum caspase-3 concentrations in non-survivor compared to survivor septic patients have been found. The objectives of this work (with the increase of sample size to 308 patients, and the determination of serum caspase-3 concentrations also on days 4 and 8 of diagnosis of severe sepsis) were to know whether an association between serum caspase-3 concentrationss during the first week, degree of apoptosis, sepsis severity, and sepsis mortality exists. We collected serum samples of 308 patients with severe sepsis from eight intensive care units on days 1, 4 and 8 to measure concentrations of caspase-3 and caspase-cleaved cytokeratin (CCCK)-18 (to assess degree of apoptosis). End point was 30-day mortality. We found higher serum concentrations of caspase-3 and CCCK-18 in non-survivors compared to survivors on days 1 (p < 0.001), 4 (p < 0.001), and 8 (p < 0.001). We found an association between serum caspase-3 concentrations on days 1, 4 and 8 of severe sepsis diagnosis and serum CCCK-18 concentrations (p < 0.001), SOFA (p < 0.001), serum acid lactic concentrations (p < 0.001), and 30-day sepsis mortality (p < 0.001). The new findings of this work were that an association between serum caspase-3 concentrations during the first week, apoptosis degree, sepsis severity, and sepsis mortality exists.
Asunto(s)
Apoptosis/fisiología , Caspasa 3/sangre , Queratina-18/sangre , Sepsis/sangre , Sepsis/mortalidad , Anciano , Femenino , Humanos , Unidades de Cuidados Intensivos , Estimación de Kaplan-Meier , Ácido Láctico/sangre , Masculino , Persona de Mediana Edad , Puntuaciones en la Disfunción de Órganos , Pronóstico , Sepsis/microbiologíaRESUMEN
OBJECTIVE: To determine if there is a relationship between environmental exposure to pesticides and the prevalence of Amyotrophic Lateral Sclerosis (ALS) in Andalusia. METHOD: We carried out a case-control study using the logistic regression method to verify the relationship between the prevalence of ALS in the area exposed to pesticides versus the unexposed area, through the Odds Ratio statistical test. RESULTS: The study population consisted of 519 individuals diagnosed with ALS between January 2016 and December 2018 according to the CMBD (Minimum Basic Data Set) as cases. In the control group, we have 8,384,083 individuals obtained from data from the National Institute of Statistics (INE). The Odds Ratio (OR) was used as a measure of association between cases and controls, obtaining an OR between 0.76 and 1.08 for the confidence interval of the CI (95%). CONCLUSIONS: Despite the existence of various studies that suggest a possible association between environmental exposure to pesticides and the risk of Amyotrophic Lateral Sclerosis, our analysis of the Andalusian population did not find significant evidence of this association.
Asunto(s)
Esclerosis Amiotrófica Lateral , Plaguicidas , Humanos , Esclerosis Amiotrófica Lateral/inducido químicamente , Esclerosis Amiotrófica Lateral/epidemiología , Plaguicidas/efectos adversos , España/epidemiología , Estudios de Casos y Controles , Exposición a Riesgos Ambientales/efectos adversosRESUMEN
Certain guidelines for the prevention of ventilator-associated pneumonia (VAP) recommend oral care with chlorhexidine, but none refer to the use of a toothbrush for oral hygiene. The role of toothbrush use has received scant attention. Thus, the objective of this study was to compare the incidence of VAP in critical care patients receiving oral care with and without manual brushing of the teeth. This was a randomized clinical trial developed in a 24-bed medical-surgical intensive care unit (ICU). Patients undergoing invasive mechanical ventilation for than 24 h were included. Patients were randomly assigned to receive oral care with or without toothbrushing. All patients received oral care with 0.12 % chlorhexidine digluconate. Tracheal aspirate samples were obtained during endotracheal intubation, then twice a week, and, finally, on extubation. There were no significant differences between the two groups of patients in the baseline characteristics. We found no statistically significant differences between the groups regarding the incidence of VAP (21 of 217 [9.7 %] with toothbrushing vs. 24 of 219 [11.0 %] without toothbrushing; odds ratio [OR] = 0.87, 95 % confidence interval [CI] = 0.469-1.615; p = 0.75). Adding manual toothbrushing to chlorhexidine oral care does not help to prevent VAP in critical care patients on mechanical ventilation.
Asunto(s)
Antiinfecciosos Locales/administración & dosificación , Neumonía Asociada al Ventilador/prevención & control , Cepillado Dental/métodos , Adulto , Anciano , Clorhexidina/administración & dosificación , Clorhexidina/análogos & derivados , Cuidados Críticos , Femenino , Humanos , Incidencia , Unidades de Cuidados Intensivos , Intubación Intratraqueal , Masculino , Persona de Mediana Edad , Oportunidad Relativa , Neumonía Asociada al Ventilador/microbiología , Respiración Artificial/efectos adversos , Tráquea/microbiologíaRESUMEN
OBJECTIVE: To determine if there is a relationship between environmental exposure to pesticides and the prevalence of Amyotrophic Lateral Sclerosis (ALS) in Andalusia. METHOD: We carried out a case-control study using the logistic regression method to verify the relationship between the prevalence of ALS in the area exposed to pesticides versus the unexposed area, through the Odds Ratio statistical test. RESULTS: The study population consisted of 519 individuals diagnosed with ALS between January 2016 and December 2018 according to the CMBD (Minimum Basic Data Set) as cases. In the control group, we have 8,384,083 individuals obtained from data from the National Institute of Statistics (INE). The Odds Ratio (OR) was used as a measure of association between cases and controls, obtaining an OR between 0.76 and 1.08 for the confidence interval of the CI (95%). CONCLUSIONS: Despite the existence of various studies that suggest a possible association between environmental exposure to pesticides and the risk of Amyotrophic Lateral Sclerosis, our analysis of the Andalusian population did not find significant evidence of this association.
RESUMEN
This positioning document describes the most important aspects of clinical ultrasonography in the internal medicine setting, from its fundamental indications to the recommended training period. There is no question as to the considerable usefulness of this tool in the standard clinical practice of internists in numerous clinical scenarios and settings (emergencies, hospital ward, general and specific consultations and home care). Ultrasonography has a relevant impact on the practitioner's ability to resolve issues, increasing diagnostic reliability and safety and providing important information on the prognosis and progression. In recent years, ultrasonography has been incorporated as a tool in undergraduate teaching, with excellent results. The use of ultrasonography needs to be widespread. To accomplish this, we must encourage structured training and the acquisition of equipment. This document was developed by the Clinical Ultrasonography Workgroup and endorsed by the Spanish Society of Internal Medicine.
RESUMEN
We have studied the effect of triiodothyronine (T3) on RNA synthesis by primary cultures of rat hepatocytes in order to ascertain whether hepatocyte transcriptional activity is directly stimulated by this hormone. The results demonstrate that T3 stimulates RNA synthesis as measured by [3H]orotic acid incorporation into RNA and by RNA polymerase activity. The responsiveness of cultured hepatocytes to T3 becomes evident only after a fairly long latency period required for the recovery of T3 nuclear binding sites. The response of RNA synthesis to T3 was absent unless the hepatocytes were simultaneously exposed to insulin and dexamethasone, indicating a permissive role of these factors in the action of T3 on RNA synthesis.
Asunto(s)
Hígado/metabolismo , ARN/biosíntesis , Triyodotironina/farmacología , Animales , Núcleo Celular/metabolismo , Células Cultivadas , ARN Polimerasas Dirigidas por ADN/metabolismo , Dexametasona/farmacología , Relación Dosis-Respuesta a Droga , Interacciones Farmacológicas , Insulina/farmacología , Hígado/efectos de los fármacos , Ácido Orótico/metabolismo , Ratas , Receptores de Superficie Celular/metabolismo , Receptores de Hormona Tiroidea , Transcripción Genética/efectos de los fármacos , Triyodotironina/metabolismoRESUMEN
The aim of the present study was to analyse the diagnostic yield of the rose Bengal test for the rapid diagnosis of human brucellosis in an emergency department in an area where the disease is endemic. The study included 711 patients diagnosed initially with brucellosis and 270 controls. Brucellosis patients were divided into three groups: group I, individuals with no regular exposure to or history of brucellosis; group II, individuals exposed repeatedly to Brucella infection; and group III, individuals infected with Brucella who had received appropriate treatment during the previous 12 months. Blood cultures were positive for 445 (62.6%) brucellosis patients, while the remaining 266 (37.4%) patients were diagnosed according to clinical and serological criteria. The overall sensitivity of the rose Bengal test was 92.9%. The specificities for groups I, II and III were 94.3%, 91.7% and 76.9%, respectively, with positive likelihood ratios of 16.5, 10.4 and 4.2, respectively. The diagnostic gain after the performance of the rose Bengal test was good or very good in patients with no previous exposure to Brucella or history of brucellosis, but poor in patients who were exposed repeatedly to Brucella or had a history of brucellosis and a low pre-test probability. Use of the rose Bengal test as the sole technique for the diagnosis of brucellosis in endemic areas should be considered very carefully in the context of patients who are exposed repeatedly to Brucella or have a history of brucellosis.
Asunto(s)
Pruebas de Aglutinación/métodos , Brucelosis/diagnóstico , Rosa Bengala , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Brucelosis/epidemiología , Servicios Médicos de Urgencia , Servicio de Urgencia en Hospital , Femenino , Humanos , Masculino , Persona de Mediana Edad , Sensibilidad y Especificidad , España/epidemiología , Coloración y EtiquetadoRESUMEN
OBJECTIVE: Ulnar variance may be a risk factor of developing scaphoid non-union. METHODS: A review was made of the posteroanterior wrist radiographs of 95 patients who were diagnosed of scaphoid fracture. All fractures with displacement less than 1mm treated conservatively were included. The ulnar variance was measured in all patients. RESULTS: Ulnar variance was measured in standard posteroanterior wrist radiographs of 95 patients. Eighteen patients (19%) developed scaphoid nonunion, with a mean value of ulnar variance of -1.34 (-/+ 0.85) mm (CI -2.25 - 0.41). Seventy seven patients (81%) healed correctly, and the mean value of ulnar variance was -0.04 (-/+ 1.85) mm (CI -0.46 - 0.38). A significant difference was observed in the distribution of ulnar variance (p<.05). These results remained significant after adjusting for age, with an OR of 0.69 (CI 0.49 to 0.95). The patients were categorized into two groups: ulnar variance less than -1mm, and ulnar variance greater than -1mm. It appears that patients with ulnar variance less than -1mm had an OR 4.58 (CI 1.51 to 13.89) with p<.007. DISCUSSION: Desai et al. concluded that radiological features of acute scaphoid fractures cannot be used to predict the likelihood of fracture union. For this reason, the existence of other risk factors was analysed. According to the results of the present study, it can be concluded that patients with scaphoid fracture and ulnar variance less than -1mm have a greater risk of developing scaphoid nonunion, OR 4.58 (CI 1.51 to 13.89) with p<.007.
Asunto(s)
Fracturas no Consolidadas/etiología , Hueso Escafoides/lesiones , Cúbito/anatomía & histología , Adulto , Femenino , Fracturas no Consolidadas/diagnóstico por imagen , Humanos , Masculino , Persona de Mediana Edad , Pronóstico , Radiografía , Estudios Retrospectivos , Factores de Riesgo , Hueso Escafoides/diagnóstico por imagen , Cúbito/diagnóstico por imagenRESUMEN
BACKGROUND AND OBJECTIVES: Conventional echocardiography is the technique of choice for assessing left ventricular function and the presence of structural heart disease in patients with heart failure. The aim of this study was to assess the diagnostic performance of handheld ultrasonography performed by a medical internist on patients with a clinical diagnosis of heart failure. PATIENTS AND METHODS: Cross-sectional observational study of 212 patients diagnosed with heart failure in a hospital center. A medical internist with basic training in echocardiography performed an examination using handheld ultrasonography and semiquantitatively assessed several variables. The patients' left ventricular systolic function was assessed, along with the cavity dimensions, significant valvular heart disease, pericardial effusion and the diameter of the inferior vena cava. RESULTS: The examination using handheld ultrasonography was conducted in less than 6minutes. The agreement between the diagnoses of the medical internist and the expert echocardiographist was very good (k>0.81) for the diameter, hypertrophy and left ventricular systolic function, valvular regurgitation, pericardial effusion and diameter of the inferior vena cava. CONCLUSIONS: Handheld echocardiography performed by a medical internist, as an extension of the physical examination of patients with heart failure, is a valid and safe test that helps increase the diagnostic performance.
RESUMEN
A polymerase chain reaction (PCR)-based assay was used to evaluate the expression of thyroid hormone receptor beta mRNA in Sertoli cells isolated from both prepubertal rat and piglet testes. The expression of an mRNA coding for the functional thyroid hormone receptor beta isoform, as established by the PCR assay, agrees with the presence of specific tri-iodothyronine (T3) -binding sites in the Sertoli cell nuclei of both species, as previously evaluated by displacement analysis. The results ratify the existence of a functional T3 receptor in the prepubertal testis and confirm the Sertoli cell as a specific target for thyroid hormone action on the developing testis.
Asunto(s)
ARN Mensajero/genética , ARN Mensajero/metabolismo , Receptores de Hormona Tiroidea/genética , Células de Sertoli/metabolismo , Animales , Secuencia de Bases , Cartilla de ADN/genética , Expresión Génica , Técnicas In Vitro , Masculino , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , Ratas , Receptores de Hormona Tiroidea/metabolismo , Maduración Sexual , Porcinos , Testículo/citología , Testículo/crecimiento & desarrollo , Testículo/metabolismo , Triyodotironina/metabolismoRESUMEN
The existence of nuclear tri-iodothyronine (T3) receptors in both Sertoli and Leydig cells isolated from immature piglet testes was investigated. The results demonstrated the presence of high-affinity (Kd = 1.09 +/- 0.25 nM), low-capacity (185 +/- 24 pg T3/mg DNA) binding sites for T3 in nuclei from freshly isolated Sertoli cells. No specific binding for T3 was observed in nuclei isolated from Leydig cells. The localization of specific T3 receptors, which might mediate the onset of thyroid hormone action, at Sertoli cell level confirms that these cells are a target for thyroid hormone and strongly sustain the role of the thyroid in the regulation of testicular functions during postnatal development.
Asunto(s)
Núcleo Celular/metabolismo , Receptores de Hormona Tiroidea/metabolismo , Células de Sertoli/metabolismo , Testículo/metabolismo , Animales , Sitios de Unión , Células Cultivadas , Células Intersticiales del Testículo/metabolismo , Masculino , Porcinos , Testículo/citologíaRESUMEN
The addition of physiological concentrations (1 nM) of tri-iodothyronine (T3) to the culture medium of Sertoli cells from prepubertal (8-day-old) rats stimulated both protein synthesis (+55%) and lactate (+50%) production, while it inhibited DNA synthesis (-30/35%) and aromatase activity (-45/50%); insignificant T3-dependent effects were observed in cultured Sertoli cells from midpubertal (28-day-old) rats. These data suggest an age-dependent role for thyroid hormone in promoting and maintaining Sertoli cell differentiation at puberty; more-over, the hormone is involved in the regulation of Sertoli cell proliferation. The present study validates the role of Sertoli cells as a specific target for T3 action at the testis level; it also demonstrates the existence of an early and critical direct influence of thyroid hormone on Sertoli cell proliferation and functional maturation.
Asunto(s)
Células de Sertoli/citología , Triyodotironina/farmacología , Animales , Aromatasa/metabolismo , Diferenciación Celular/efectos de los fármacos , División Celular/efectos de los fármacos , Células Cultivadas , ADN/biosíntesis , Lactatos/metabolismo , Ácido Láctico , Masculino , Biosíntesis de Proteínas , Ratas , Ratas Wistar , Células de Sertoli/efectos de los fármacos , Células de Sertoli/metabolismoRESUMEN
The relationship between thyroid activity and Sertoli cell function has been investigated in prepubertal rats. Male 28-day-old Wistar rats were used to prepare Sertoli cells by sequential enzyme digestion of the testes. Hypothyroidism, induced by oral administration of methimazole from the day of birth, was characterized by a severe retardation of body and testis growth and a net inhibition of the increase in Sertoli cell gamma-glutamyl transpeptidase (GGT) activity as well as in androgen-binding protein (ABP) and lactate production, which normally occur during postnatal development of Sertoli cells. The functional parameters of Sertoli cells from hypothyroid 28-day-old rats approximated to those of cells from euthyroid 15-day-old animals. These results are consistent with the impairment of protein synthesis in Sertoli cells from hypothyroid rats compared with controls. Body and testis growth were improved and Sertoli cell functions were restored with 3,3',5-tri-iodothyronine (T3) replacement therapy. An excess of T3 in the serum, induced by daily i.p. injections of T3 (100 micrograms/kg body wt) during the last week before the rats were killed, failed to induce changes in body and testis growth or in the activity of GGT and lactate dehydrogenase of Sertoli cells. Cells from hyperthyroid rats exhibited a specific decrease in ABP production. These results indicate that thyroid hormone is necessary for the postnatal maturation of Sertoli cell function and suggest a regulatory role of the hormone on gametogenic development in the prepubertal rat.
Asunto(s)
Células de Sertoli/fisiología , Hormonas Tiroideas/fisiología , Envejecimiento/metabolismo , Proteína de Unión a Andrógenos/metabolismo , Animales , Peso Corporal , Hipotiroidismo/inducido químicamente , L-Lactato Deshidrogenasa/metabolismo , Lactatos/biosíntesis , Masculino , Metimazol , Tamaño de los Órganos , Ratas , Ratas Endogámicas , Células de Sertoli/enzimología , Testículo/anatomía & histología , Tiroxina/sangre , Triyodotironina/farmacología , gamma-Glutamiltransferasa/metabolismoRESUMEN
Previous work has demonstrated that thyroid hormones influence testis development. Specific receptors for tri-iodothyronine (T3) have been demonstrated in Sertoli cells. The aim of the present study was to examine the possible effect of thyroid hormone on its own receptor during pubertal development by evaluating the influence of thyroid status on T3-binding capacity, -binding affinity and receptor occupancy in nuclei isolated from immature rat testes. The binding capacity for T3 of nuclei from rat testis significantly decreased during pubertal development, being 375 +/- 32, 117 +/- 15 and 44 +/- 7 fmol/mg DNA in 7-, 21- and 35-day-old rats respectively, whereas the affinity of binding, as evaluated by the dissociation constant (Kd), did not change. Early induced hypothyroidism significantly affected the time-course of the postnatal decline of nuclear T3 receptors in the testis. At 21 days of age, the binding capacity for T3 in the testis of methimazole-treated rats was significantly higher with respect to euthyroid controls, being 173 +/- 21 and 117 +/- 15 mol/mg DNA respectively, while the Kd was unaffected. T3 replacement therapy completely prevented changes in T3 receptor number induced by hypothyroidism without modifying the Kd. Our results indicate that nuclear T3 receptors in the developing rat testis are modulated by thyroid hormone.
Asunto(s)
Receptores de Hormona Tiroidea/metabolismo , Maduración Sexual/fisiología , Testículo/crecimiento & desarrollo , Triyodotironina/fisiología , Animales , Núcleo Celular/metabolismo , Hipotiroidismo/metabolismo , Masculino , Unión Proteica/fisiología , Ratas , Ratas Wistar , Testículo/metabolismoRESUMEN
The relationship between thyroid function and testicular development in the rat was investigated. Hypothyroidism was induced during fetal or post-natal life by adding methimazole (MMI) to the drinking water of pregnant or lactating mothers. A group of newborn rats was treated with MMI and i.p. injections of L-tri-iodothyronine (L-T3). Hypothyroidism was shown by the reduced serum levels of total T3 and of total thyroxine (T4) in pregnant mothers and in pubertal rats. Testes were studied using light microscopy at 18 and 21 days post coitum or during puberty (21, 35 and 50 days after birth); serum levels of gonadotrophins were also evaluated in pubertal rats. Hypothyroidism had no effect on testicular development during fetal life and when induced in newborn rats it was associated at puberty with reduced serum levels of FSH and LH and with delayed maturation of the testis compared with control rats. The delay in maturation consisted of a reduction in the diameter of seminiferous tubules, and a reduction in the number of germ cells per tubule; this was associated with increased degeneration and arrested maturation of germ cells. In addition, Sertoli cells demonstrated retarded development, as indicated by a delay in the appearance of cytoplasmic lipids and in the development of a tubule lumen. Hormonal and morphological abnormalities were absent in rats treated with MMI plus L-T3. In conclusion, hypothyroidism occurring soon after birth caused reduced levels of gonadotrophins in the serum and a delay in pubertal spermatogenesis, possibly due to retarded differentiation of the Sertoli cells.
Asunto(s)
Maduración Sexual/fisiología , Testículo/fisiología , Hormonas Tiroideas/fisiología , Animales , Hormona Folículo Estimulante/sangre , Hipotiroidismo/inducido químicamente , Hormona Luteinizante/sangre , Masculino , Metimazol , Ratas , Ratas Endogámicas , Túbulos Seminíferos/anatomía & histología , Células de Sertoli/fisiología , Espermatozoides/citología , Testículo/embriología , Testículo/crecimiento & desarrollo , Tiroxina/fisiología , Triyodotironina/fisiologíaRESUMEN
A possible role of tri-iodothyronine (T3) on the interplay between testicular steroids and Sertoli cells has been investigated on the basis of previous findings demonstrating a direct inhibitory influence of T3 on aromatase activity and oestradiol production in peripuberal Sertoli cells. In this context, the present study was focused on the effects of T3 on oestrogen receptor (ER) and androgen receptor (AR) contents in the cytosol and nucleus of Sertoli cells isolated from 2-, 3- and 4-week-old euthyroid, hypothyroid and hypothyroid treated rats. Hypothyroidism was induced by the oral administration of 0.025% methimazole (MMI) from birth until the rats were killed at 2, 3 and 4 weeks of age. Half of the MMI-treated animals were injected i.p. with L-tri-iodothyronine (T3; 3 micrograms/100 g body weight) during the last week before death. Sertoli cells from all groups were initially cultured under basal conditions for the first 24 h and subsequently in the presence of testosterone with or without T3 for an additional 24 h. Hypothyroidism was associated with severe impairment of body as well as testicular growth. Euthyroid ERs showed an elevated Kd (0.76 nM) which was similar in the different age groups investigated. The in vitro addition of T3 or testosterone induced a decrease in ER content and this decrease was greater after exposure to both hormones. In 2- and 3-week-old hypothyroid rats, ER content was markedly increased and was reversed in euthyroid rats when T3 was given in vivo. When ERs were assayed in the Sertoli cell nucleus and cytoplasm of 2- and 3-week-old animals, a strong relationship in ER content in the two cellular compartments was observed. Neither of the hormones tested seemed to affect the AR content in the nucleus significantly, while the in vitro addition of testosterone or T3 or both hormones together augmented the ARs in the cytosol to a greater extent, resulting in an increase in their total (cytosolic and nuclear) content in the cells. The present data suggest that T3 down-regulates ERs and up-regulates ARs in peripuberal Sertoli cells. The additive effect of testosterone and T3 in up-regulating ARs could possibly involve a role for T3 in influencing the androgen responsiveness of the Sertoli cells during spermatogenesis.
Asunto(s)
Hipotiroidismo/metabolismo , Receptores Androgénicos/metabolismo , Receptores de Estrógenos/metabolismo , Células de Sertoli/metabolismo , Triyodotironina/farmacología , Animales , Núcleo Celular/metabolismo , Células Cultivadas , Citosol/metabolismo , Estradiol/farmacología , Masculino , Metimazol , Metribolona/farmacología , Unión Proteica , Ratas , Ratas Wistar , Células de Sertoli/efectos de los fármacos , Testosterona/farmacologíaRESUMEN
The aim of the present study was to investigate the influence of thyroid hormones on androgen metabolism in Sertoli cells isolated from 3- and 4- week-old rats. Hypothyroidism was induced by the oral administration of 0.025% methimazole (MMI) from birth until the rats were killed at 3 and 4 weeks of age. Half of the MMI-treated animals were injected i.p. with L-triiodothyronine (T3 3 micrograms/100 g body weight) during the last week before death. Sertoli cells from all groups were initially cultured under basal conditions for the first 24 h and subsequently in the presence of testosterone with or without T3 for an additional 24 h. Hypothyroidism was associated with severe impairment of body as well as testicular growth. Indeed, body and testicular weights were similar in 4-week-old hypothyroid animals to those in 3-week-old control rats. Testosterone metabolism in Sertoli cells isolated from 3- and 4-week-old hypothyroid rats was mainly expressed by the lowering of 5 alpha-dihydrotestosterone + androstane 3 alpha, 17 beta-diol and an enhanced formation of 5 alpha-reduced steroids with poor androgenic properties (e.g. 5 alpha-androstane, 3, 17 alpha-dione (androstanedione), 5 alpha-androstane, 3-ol-17-one (androsterone)). Treatment of the same group of animals with T3 in vivo and in vitro did not influence the pattern of 5 alpha-reductase steroids substantially. The most striking finding in the Sertoli cells of 3-week-old hypothyroid rats was the dramatic enhancement of oestradiol formation which persisted to a lesser extent 1 week later.(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Andrógenos/metabolismo , Hipotiroidismo/metabolismo , Células de Sertoli/metabolismo , Maduración Sexual/fisiología , Triyodotironina/farmacología , Androstano-3,17-diol/metabolismo , Androstenodiona/metabolismo , Androsterona/metabolismo , Animales , Peso Corporal/fisiología , Células Cultivadas , Dihidrotestosterona/metabolismo , Estradiol/metabolismo , Masculino , Metimazol , Tamaño de los Órganos/fisiología , Ratas , Ratas Wistar , Células de Sertoli/efectos de los fármacos , Testículo/anatomía & histología , Testosterona/metabolismoRESUMEN
The existence of specific triiodothyronine (T3) receptors in cultured rat Sertoli cells was investigated by evaluating the affinity and capacity of nuclear binding for T3. The results demonstrate the presence of high affinity (Ka = 0.15 +/- 0.02 X 10(10) M-1), low capacity (1.35 +/- 0.07 pmol T3/mg DNA) binding sites for T3 in rat Sertoli cell nuclei. It is demonstrated that, within the developing testis, the major localization of nuclear T3 receptors is in Sertoli cells.
Asunto(s)
Receptores de Hormona Tiroidea/análisis , Células de Sertoli/ultraestructura , Animales , Núcleo Celular/metabolismo , Núcleo Celular/ultraestructura , Células Cultivadas , Masculino , Ratas , Ratas Endogámicas , Triyodotironina/metabolismoRESUMEN
The effects of thyroid hormone on insulin-like growth factor I (IGF-I) production by Sertoli cells isolated from immature rats have been investigated. In Sertoli cells from hypothyroid rats the production of IGF-I was significantly lower than in controls and was greatly stimulated by the administration of triiodothyronine (T3) in vivo. The in vitro addition of physiological doses of T3 (1 nmol/l) significantly increased the production of IGF-I by cultured Sertoli cells indicating a direct action of the hormone on local IGF-I production. Our results suggest the involvement of IGF-I in the thyroid hormone-dependent maturation of testicular function.