La separación materna durante la lactancia altera los niveles basales del sistema neuroendocrino en ratas adolescentes y adultas / Maternal separation during nursing alters basal neuroendocrine levels in juvenile and adult rats

Introducción. En diversos modelos animales, incluido el de la separación materna durante la lactancia, se ha demostrado que las experiencias tempranas adversas, como el maltrato, el abandono materno y el estrés psicosocial, pueden favorecer el desarrollo de algunas enfermedades mentales, pero no se han descrito completamente varios de los cambios que se producen en el sistema neuroendocrino. Objetivo. Determinar si la separación materna durante la lactancia modificaba los niveles basales de neurohormonas como la corticosterona, la corticotropina (ACTH), la oxitocina y la vasopresina (ADH), en ratas jóvenes (35 días) y adultas (90 días). Materiales y métodos. Se separaron ratas Wistar de sus madres durante dos periodos de tres horas diarias a lo largo de los 21 días de lactancia. A los 35 y 90 días se tomaron muestras de los grupos de las ratas de control y de las separadas de la madre, para obtener el suero y posteriormente medir cada una de las hormonas mediante un ensayo inmunoenzimático. Resultados. Las concentraciones de corticosterona fueron mayores en las hembras adultas de control que en el resto de los grupos, y menores en los machos adultos de control. Las de ACTH fueron mayores en los machos y hembras jóvenes separadas de la madre que en los grupos de adultos. Los niveles de oxitocina fueron significativamente mayores en las hembras adultas separadas de la madre que en los otros grupos y significativamente menores en los machos adultos. En cuanto a la vasopresina, los grupos separados de la madre tuvieron concentraciones menores, en comparación con los grupos de jóvenes y adultos de control. Conclusiones. Estos resultados muestran que el estrés temprano al que fueron sometidas las ratas, produjo cambios en las respuestas del eje hipotálamo-hipófisis-suprarrenal, las cuales variaron según el sexo y la edad.

Introduction: Work with different animal models including that of maternal separation during nursing has shown that early adverse experiences such as abuse, maternal abandonment and psychosocial stress may favor the development of various psychopathologies. However, several neuroendocrine changes have not been completely described yet. Objective: To establish whether maternal separation during nursing modifies the basal levels of neurohormones such as corticosterone, ACTH, oxytocin and vasopressin in juvenile and adult rats (aged 35 and 90 days, respectively). Materials and methods: Wistar rats were separated from their mothers for two periods of 3 hours per day during the 21 days of nursing. Once these rats had reached 35 and then 90 days of age, blood samples were taken from both the separated and control groups to obtain serum for immunoenzymatic assays and measure the levels of each of the hormones. Results: Concentrations of corticosterone were higher in control adult females in comparison with the rest of the groups and lower in the control adult males. Those of ACTH were higher in the separated young males and females than in the adult groups. Oxytocin levels were significantly higher in the separated adult females in comparison with the other groups and significantly lower in the adult males. With respect to vasopressin, the separated groups had lower concentrations than the young and adult control groups. Conclusions: These results show that the early stress to which rats were submitted produced changes in the basal responses of the hypothalamic-pituitary-adrenal axis, that these responses were distinct in males and females and that they also differed according to age.

Diagnosis of adrenal failure in critically ill patients / Diagnóstico de insuficiência adrenal em pacientes críticos

In the last two decades there was important evolution on the knowledge of the function of the hypothalamic-pituitary-adrenal axis. In the last decade, the expression "relative adrenal insufficiency" (RAI) was created, and more recently "critical illness-related corticosteroid insufficiency" (CIRCI) was used to designate those patients in which cortisol production was not sufficiently increased in stress situations. Patients with CIRCI have elevated hospital morbidity and mortality. Currently, there is a wide discussion about diagnostic criteria for this dysfunction. Besides basal cortisol, some publications now study the role of other tests, such as cortrosyn test - either in low (1 μg) or high doses (250 μg); free cortisol, salivary cortisol, metyrapone test and others. With this review, we aimed at summarizing the results of the most influent papers that intended to define diagnostic criteria for CIRCI. We also suggest an approach for CIRCI diagnosis and make it clear that the decision about steroid therapy in septic shock patients is matter apart from RAI.

Nas últimas décadas, houve uma importante evolução no conhecimento sobre a função do eixo hipotálamo-pituitária-adrenal. Na última década, foi cunhada a expressão "insuficiência adrenal relativa" (IAR) e, mais recentemente, a expressão "insuficiência adrenal relacionada à doença grave" (CIRCI) foi utilizada para designar aqueles pacientes nos quais a produção de cortisol não era suficientemente elevada em situações de estresse. Pacientes com CIRCI apresentam elevada morbidade e mortalidade em hospitais. Atualmente, há uma ampla discussão sobre os critérios de diagnóstico para essa desordem. Além do cortisol basal, algumas publicações analisaram o papel de outros testes, tais como o teste de estímulo com ACTH (cortrosina), com doses baixas (1 mg) ou altas (250 mg), cortisol livre, cortisol salivar, teste da metirapona e outros. O objetivo desta revisão foi resumir os resultados dos artigos mais importantes que buscaram definir os critérios de diagnóstico para a CIRCI. Também sugerimos uma abordagem para o diagnóstico da CIRCI e deixamos claro que a decisão sobre a terapia com esteroides em pacientes em choque séptico é uma questão separada da IAR.

Syndrome of inappropriate secretion of antidiuretic hormone associated with strongyloidiasis.

We report a case of syndrome of inappropriate secretion of antidiuretic hormone (SIADH) with accompanying severe strongyloidiasis in a 52-year-old male. On admission, he showed drowsiness and emaciation with severe hyponatremia. We gave sodium (saline or salts) in an i.v. drip infusion and orally without improvement. A urinalysis and plasma osmotic pressure test indicated SIADH, therefore, treatment was changed to restrict his sodium intake. The hyponatremia gradually improved initially, but the appetite loss, nausea, and hyponatremia continued. Endoscopy revealed white patches on the stomach wall and histopathological examination revealed infestation of the mucosal epithelium with numerous Strongyloides stercoralis larvae. Ivermectin treatment was then initiated and the abdominal symptoms and hyponatremia gradually resolved. We carefully investigated the underlying cause of the SIADH, such as disease of the central nervous system, lung cancer, and other malignancies, but no abnormality or clear cause could be found. We concluded that the patient developed SIADH secondary to severe S. stercoralis infection.

combined effects of exercise and post dehydration water drinking on plasma argenine vasopressin, plasma osmolality and body temperature in healthy males

The purpose of this study was to investigate the effect of exercise and post dehydration water drinking on variations in plasma arginine vasopressin [PAVP], plasma osmolality [Posm] and tympanic temperature [Ttym] in healthy males. Eight healthy young males [27.4 +/- 0.8 yrs old] volunteered for the study. They performed constant work exercise, at a rate of 60 rpm at 50% of individual work load for VO2 peak for 30 minutes. Six blood samples [at minutes 0, 15 and 30 during exercise and at minutes 3, 15 and 30 after termination of exercise] were obtained through an indwelling venous cannula. Plasma concentrations for Na+, and AVP were determined. Posm was calculated using Na+ concentrations. Simultaneous variations in Ttym were also determined. Our results demonstrated a positive correlation between increase in PAVP and both Posm and Ttym during exercise but not during the recovery period. When exercise was combined with water drinking a fast and significant suppression in PAVP occurred [P<0.05]. These results suggest that Posm and Ttym have no significant effect on AVP secretion post exercise, and thus other factors must be involved in AVP secretion during post exercise recovery period

Hypodipsic hypernatremia with intact AVP response to non-osmotic stimuli induced by hypothalamic tumor: A case report

Anatomical lesions of hypothalamic area associated with hypodipsic hypernatremia have been reported only rarely. We report here a case of hypodipsic hypernatremia induced by a hypothalamic lesion. A 25-yr-old man, who had been treated with radiation for hypothalamic tumor 5-yr before, was admitted for evaluation of hypernatremia and hypokalemia. He never felt thirst despite the elevated plasma osmolality and usually refused to drink intentionally. Plasma arginine vasopressin (AVP) level was normal despite the severe hypernatremic hyperosmolar state and urine was not properly concentrated, while AVP secretion was rapidly induced by water deprivation and urine osmolality also progressively increased to the near maximum concentration range. All of these findings were consistent with an isolated defect in osmoregulation of thirst, which was considered as the cause of chronic hypernatremia in the patient without an absolute deficiency in AVP secretion. Hypokalemia could be induced by activation of the renin-angiotensin-aldosterone system as a result of volume depletion. However, inappropriately low values of plasma aldosterone levels despite high plasma renin activity could not induce symptomatic hypokalemia and metabolic alkalosis. The relatively low serum aldosterone levels compared with high plasma renin activity might result from hypernatremia. Hypernatremia and hypokalemia were gradually corrected by intentional water intake only.