A systematic review of hormone levels, biomarkers of cellular injury and oxidative stress in multi-stressor military field training exercises

ABSTRACT The fundamental objective of military field training exercises (FTX) is to prepare military personnel for real-life operations through simulated scenarios. These training sessions often require extreme physical efforts with prolonged, high-intensity exercises that can be combined with food restrictions and partial, or total, sleep deprivation. Such conditions can compromise an individual's physical performance and cause tissue damage, thus affecting their health. This study aimed to perform a systematic review of the literature to identify studies that measured the changes in hormone levels and biomarkers of cellular injury and oxidative stress resulting from FTX with high levels of energy expenditure combined with food and sleep restrictions. PubMed and the Scopus database were searched for articles that combined physical effort/food restriction/sleep deprivation with military training. The initial database search identified 158 articles that were reduced to 18 after confirmation. Significant reductions were reported in thyroid hormones, T3, T4, and anabolic hormones such as testosterone, insulin and androstenedione. An exception for GH was found, which increased throughout FTX. Less distinct responses to FTX were observed with cortisol, TSH and LH. The presence of biomarkers for cellular damage (myoglobin, TNF, and CRP) and increased immune response activities were also described. The scarcity of information on oxidative stress, analyses of cellular injury and biomarkers of inflammatory responses warrants the future study of these topics, which could be helpful in facilitating the safe and effective physical preparations of the members of the armed forces.

Household food insecurity, dental caries and oral-health-related quality of life in Brazilian Indigenous adults / Insegurança alimentar domiciliar, cárie dentária e qualidade de vida relacionada à saúde bucal em Indígenas adultos brasileiros

Abstract Food insecurity is a complex phenomenon that affects the health and wellbeing of vulnerable families. The aim of this study was to investigate the relationship between household food insecurity, dental caries, oral health-related quality of life, and social determinants of health among Indigenous adults. A cross-sectional study was conducted among Kaingang adults aged 35-44 years old from the Guarita Indigenous Land, Brazil. Food insecurity was assessed through the EBIA scale. Dental caries was assessed using the DMFT index. Participants answered the OHIP-14 questionnaire and a structured interview. Descriptive and multivariate analyzes using Poisson regression models were performed. The final sample included 107 adults from 97 households. Approximately 95% lived in food insecure families. Severe food insecurity was present in 58% of the households. The phenomenon was associated to the Bolsa Família benefit, household size, and greater perception of oral health impacts on quality of life. The high number of families affected by food insecurity reveals the social vulnerability of the Kaingang people. Food insecurity in Kaingangs adults is associated to oral health perception and social determinants of health.

Resumo Insegurança alimentar é um fenômeno complexo que afeta a saúde e o bem-estar de famílias vulneráveis. Este estudo objetivou investigar a relação entre insegurança alimentar domiciliar, cárie dentária, qualidade de vida relacionada à saúde bucal, e determinantes sociais de saúde entre indígenas adultos. Foi conduzido um estudo transversal com adultos Kaingang entre 35-44 anos da Terra Indígena Guarita, Brasil. Insegurança alimentar foi avaliada pela escala EBIA. Cárie dentária foi avaliada pelo índice CPOD. Participantes responderam o questionário OHIP-14 e uma entrevista estruturada. Foram realizadas análises descritivas e multivariadas usando modelos de regressão de Poisson. A amostra incluiu 107 adultos Kaingang de 97 domicílios. Aproximadamente 95% dos participantes viviam em famílias com insegurança alimentar. Insegurança alimentar grave esteve presente em 58% dos domicílios. O fenômeno foi associado ao Bolsa Família, densidade familiar e percepção dos impactos da saúde bucal na qualidade de vida. O alto número de famílias afetadas pela insegurança alimentar revela a vulnerabilidade social do povo Kaingang. Insegurança alimentar em adultos Kaingang está associada à percepção da saúde bucal e determinantes sociais da saúde.

Breakfast skipping and cardiometabolic risk factors in adolescents: Systematic review

ABSTRACT OBJECTIVE To systematically review the results of the association between breakfast skipping and cardiometabolic risk factors in adolescents. METHODS The articles were searched in May 2020 from PubMed, Virtual Health Library, Scopus, Web of Science and Scientific Electronic Library Online (SciELO). The review included observational studies conducted with adolescents (10-19 years old), which estimated the association of breakfast skipping with at least one outcome (markers of body adiposity, blood pressure, serum lipid and glucose levels). Regarding the risk of bias, the articles were evaluated using the Research Triangle Institute (RTI) Item Bank on bias risk and accuracy of observational studies. The quality of the evidence was assessed by the Grade rating. RESULTS A total of 43 articles involving 192,262 participants met the inclusion criteria and were considered in this review. The prevalence of breakfast skipping ranged from 0.7% to 94% and 60.5% of studies were classified with low risk of bias. The significant association between breakfast skipping and cardiometabolic risk factors was found in twenty-nine cross-sectional articles (n = 106,031) and four longitudinal articles (n = 5,162) for excess adiposity, in three articles (n = 8,511) for high total cholesterol levels, low-density lipoprotein and triglycerides, and in three studies (n = 6,303) for high blood pressure levels. However, there was no significant association between breakfast skipping and glycemic profile. According to the Grade rating, all the associations had low quality of evidence. CONCLUSION The results of this review suggest that breakfast skipping is associated with cardiometabolic risk factors in adolescents aged 10 to 19 years. However, considering the low quality of the evidence, the present results should be interpreted carefully. In addition, our findings highlight the importance of standardizing the definition of breakfast skipping and that more prospective studies are needed to determine how skipping breakfast can affect cardiometabolic risk factors in the long time.

Rebound Feeding in the Wake of Short-Term Suspension of Food Intake Differs in the Presence of Estrous Cycle Peak versus Nadir Levels of Estradiol

BACKGROUND: Short-term interruption of feeding is ordinary in modern life but negatively impacts appetite control and body weight. Estradiol (E) imposes long-term inhibitory tonus on food consumption; however, E influence on energy repletion secondary to food deprivation (FD) is unclear. This study investigated the hypothesis that E signal strength regulates hyperphagic responses to FD of varying duration. METHODS: Ovariectomized female rats were implanted with E-containing silastic capsules (30 [E-30] or 300 µg [E-300]/mL) to replicate plasma concentrations at cycle nadir versus peak levels. RESULTS: Data show that food intake was increased equally in E-30 and E-300 rats after 12 hours of food deprivation (FD-12); yet, FD of 18 hours (FD-18) amplified refeeding by E-300 versus E-30. Caudal fourth ventricular administration of the 5′-monophosphate-activated protein kinase (AMPK) inhibitor compound C (Cc) did not modify FD-induced hyperphagia in E-30 (regardless of FD interval) or E-300 animals exposed to FD-12, but diminished refeeding after FD-18 in E-300 rats. Cc-reversible hyperglycemia occurred in refed FD-18 groups. Serum insulin was resistant to FD-12 plus refeeding, but was elevated by AMPK-dependent mechanisms in refed E-300 FD-18 rats; equivalent Cc-insensitive decrements in circulating leptin occurred in all FD groups. CONCLUSION: Current results show that estrous cycle peak, but not baseline, E levels engage hindbrain AMPK signaling to intensify hyperphagia in response to prolongation of FD. Observations of hindbrain AMPK-dependent hyperglycemia, alongside elevated insulin secretion, in refed rats exposed to FD-18 implicate this sensor in insulin resistance mechanisms of glucose partitioning in response to this metabolic imbalance.

Insegurança alimentar em povos de terreiros / Food insecurity in people of terreiros

INTRODUÇÃO: O conceito de segurança alimentar é compreendido como a realização do direito de todos ao acesso regular e permanente a alimentos de qualidade em quantidade suficiente, sem afetar outras necessidades essenciais. OBJETIVO: Estimar a prevalência de insegurança alimentar intrafamiliar em povos de terreiros e verificar a associação com indicadores socioeconômicos. MÉTODOS: Estudo transversal que investigou a situação de insegurança alimentar em povos de terreiros de Teresina, Piauí, cuja amostra foi constituída por 137 casas ativas no período de agosto de 2011 a julho de 2012. Foram instrumentos de coleta de dados a Escala Brasileira de Insegurança Alimentar e um questionário sociodemográfico aplicados ao pai/mãe de santo, após consentirem formalmente sua participação na pesquisa. Para análise das variáveis e da insegurança alimentar, foi utilizado o teste χ2. RESULTADOS: A insegurança alimentar esteve presente em 79,6% dos domicílios, sendo 29,9% de insegurança alimentar leve, 33,6% na forma moderada e 16,1% na grave. Nos domicílios com menores de 18 anos, a prevalência de insegurança alimentar grave foi maior (22,7%) se comparada aos domicílios que possuíam moradores com 18 anos ou mais (14,7%). As variáveis independentes como rendimento mensal e tipo de moradia apresentaram associação inversamente significante à insegurança alimentar. CONCLUSÃO: Os resultados expressam a gravidade da situação de insegurança alimentar em povos de terreiro em Teresina, indicam a violação do direito humano à alimentação adequada vivenciada por esse grupo e reforçam a necessidade do poder público agir mais efetivamente com ações de proteção social junto a esses povos.

INTRODUCTION: The concept of food security is understood as the realization of everyone’s right to regular and permanent access to quality food in sufficient quantity, without affecting other essential needs. OBJECTIVE: To estimate the prevalence of intrafamily food insecurity in people of terreiros and verify the association with socioeconomic indicators. METHODS: Cross-sectional study that investigated the food insecurity of people in terrains in Teresina, Piauí, Brazil. The sample consisted of 137 active houses from August 2011 to July 2012. The Brazilian Food Insecurity Scale and the sociodemographic questionnaire were the instruments of data collection applied to pai/mãe de santo, after formally consent to their participation in the research. To analyze variables and food insecurity, the χ2 test was used. RESULTS: Food insecurity was present in 79.6% of households, with 29.9% in mild food insecurity, 33.6% in moderate and 16.1% in severe. In households with children under 18 years of age, the prevalence of severe food insecurity was higher (22.7%) than in households with residents who were 18 years old or older (14.7%). Independent variables such as monthly income and housing type showed significant association with food insecurity. CONCLUSION: The results express the severity of food insecurity of people in the terrains of Teresina, Piauí, Brazil, indicating a violation of the human right to adequate food experience in this group and reinforcing the necessity for public authorities to act more effectively with social protection actions for these people.

Comparative analysis of blood glucose changes of different strains of mice under food and/or water deprivation / 军事医学

Objective To provide reference on the difference in blood glucose metabolism between different mouse strains by comparing blood glucose changes under food and /or water deprivation.Methods C57BL/6J mice, BALB/c mice,and ICR mice used in this study were divided into four groups:control group, food deprivation group, water depriva-tion group and food &water deprivation group .Their blood glucose was measured within 12 hours under various stresses . Results and Conclusion There are different blood glucose regulation patterns in different mice strains .The blood glucose level of C57BL/6J mice is usually higher than that of the BALB/c and ICR mice, while the of blood glucose level BALB/c mice stays relatively stable , and the ICR mice have the widest range of blood glucose levels upon these stresses .Accord-ing to our data, the difference in blood glucose metabolism between different mouse strains should be taken into considera -tion in blood glucose related studies for proper interpretation and design of experiments .

How does protein malnutrition or food deprivation interfere with the growth of the epiphyseal plate in animals? / Cómo interfieren la desnutrición protéica o la privación alimentaria en el crecimiento de la placa epifisaria de animales?

The aim of this study was to conduct a literature review of impacts of protein malnutrition and/or early food deprivation on the formation of the growth plate in young animals. A search was performed using the databases PubMed/MEDLINE, LILACS, SciELO and the Cochrane Library, without language restrictions or any limit as to year. Initially, 150 articles were identified, however, after application of the inclusion and exclusion criteria only five remained. In three studies the nutritional stress was due to protein malnutrition, another due to fasting and the fifth was due to food restriction. All the studies had some methodological omissions. The studies included in this review-demonstrated corroboration in the results obtained, regardless of whether the animals had been subjected to protein malnutrition, fasting or food restriction. The findings uncovered were reduction in height of the epiphyseal plate, in the number of proliferative and hypertrophic chondrocytes, in the bone growth rate and in the longitudinal length of the bone in animals subjected to nutritional stress. In this systematic review, it was possible to observe the susceptibility of the epiphyseal plate in the first place, and secondarily, of the long bones to the effects of nutritional stress by means of protein malnutrition or food deprivation applied in young animals.

El objetivo fue realizar una revisión de la literatura sobre el impacto de la desnutrición proteica y/o privación de alimentos en la temprana formación de la placa de crecimiento en animales jóvenes. La búsqueda fue realizada en las bases de datos PubMed/MEDLINE, LILACS, SciELO y Biblioteca Cochrane sin restricción de lengua o límite de año. Fueron identificados inicialmente ciento cincuenta artículos que, posterior a la aplicación de los criterios de inclusión y exclusión, solo quedaron cinco. En tres estudios el estrés nutricional fue causado por la desnutrición proteica, otro al ayuno y el tercero fue por restricción alimentaria. Todos los estudios presentaban algunas omisiones metodológicas. Las investigaciones incluidas en esta revisión demostraron concordancia en sus resultados obtenidos, independientemente que los animales hayan sido sometidos a desnutrición proteica, ayuno o restricción alimentaria. Los datos obtenidos mostraron que los animales sometidos al estrés nutricional presentaron una reducción en la altura de la placa epifisaria, en el número de condrocitos proliferativos e hipertróficos, en la tasa de crecimiento óseo y en la longitud ósea. En esta revisión sistemática fue posible observar que los efectos del estrés nutricional, a través, de desnutrición proteica o de la privación alimentaria aplicada en animales jóvenes presentan, en primer lugar, una susceptibilidad de la placa epifisaria y de los huesos largos de manera secundaria.

Effect of Food Deprivation on a Delayed Nonmatch-to-place T-maze Task

Food deprivation can affect performance on difficult cognitive task, such as the delayed nonmatch-to-place T-maze task (DNMT). The importance of food deprivation on maintaining high motivation for DNMT task has been emphasized, but not many studies have investigated the optimal conditions for depriving rodents to maximize performance. Establishing appropriate conditions for food deprivation is necessary to maintain DNMT task motivation. We applied different conditions of food deprivation (1-h food restriction vs. 1.5-g food restriction; single caging vs. group caging) and measured body weight and the number of correct choices that 8-week-old C57BL/6J mice made during the DNMT task. The 1.5-g food restriction group maintained 76.0+/-0.6% of their initial body weight, but the final body weight of the 1-h food restriction condition group was reduced to 62.2+/-0.8% of their initial body weight. These results propose that 1.5-g food restriction condition is effective condition for maintaining both body weight and motivation to complete the DNMT task.

cAMP/PKA Agonist Restores the Fasting-Induced Down-Regulation of nNOS Expression in the Paraventricular Nucleus

Gene expression of neuronal nitric oxide synthase (nNOS) changes in the hypothalamic paraventricular nucleus (PVN) depending on feeding conditions, which is decreased during food deprivation and restored by refeeding, and phosphorylated cAMP response element binding protein (pCREB) was suggested to play a role in its regulation. This study was conducted to examine if the fasting-induced down-regulation of the PVN-nNOS expression is restored by activation of cAMP-dependent protein kinase A (cAMP/PKA) pathway. Freely moving rats received intracerebroventricular (icv) injection of cAMP/PKA activator Sp-cAMP (40 nmol) or vehicle (sterilized saline) following 48 h of food deprivation. One hour after drug injections, rats were transcardially perfused with 4% paraformaldehyde, and the PVN tissues were processed for nNOS or pCREB immunohistochemistry. Sp-cAMP significantly increased not only nNOS but also pCREB immunoreactivities in the PVN of food deprived rats. Fasting-induced down-regulation of the PVN-nNOS was restored by 1 h after the icv Sp-cAMP. Results suggest that cAMP/PKA pathway may mediate the regulation of the PVN-nNOS expression depending on different feeding conditions.

Influence of food restriction on lipid profile and spontaneous glucose levels in male rats subjected to paradoxical sleep deprivation

OBJECTIVES: The purpose of this study was to determine the paired consequences of food restriction and paradoxical sleep deprivation on lipid profile and spontaneous glucose levels in male rats. METHOD: Food restriction began at weaning, with 6 g of food being provided per day, which was subsequently increased by 1 g per week until reaching 15 g per day by the eighth week. At adulthood, both rats subjected to food restriction and those fed ad libitum were exposed to paradoxical sleep deprivation for 96 h or were maintained in their home-cage groups. RESULTS: Animals subjected to food restriction exhibited a significant increase in high-density lipoprotein levels compared to animals that were given free access to food. After the paradoxical sleep deprivation period, the foodrestricted animals demonstrated reduced concentrations of high-density lipoprotein relative to their respective controls, although the values for the food-restricted animals after sleep deprivation were still higher than those for the ad libitum group. The concentration of low-density lipoproteins was significantly increased in sleep-deprived animals fed the ad libitum diet. The levels of triglycerides, very low-density lipoproteins, and glucose in foodrestricted animals were each decreased compared to both ad libitum groups. CONCLUSION: These results may help to illustrate the mechanisms underlying the relationship between sleep curtailment and metabolism and may suggest that, regardless of sleep deprivation, dietary restriction can minimize alterations in parameters related to cardiovascular risk.

Estratégia alimentar com ciclos de restrição e realimentação no desempenho produtivo de juvenis de tilápia do Nilo da linhagem GIFT / Feeding strategies with cycles of restriction and refeeding on growth performance of Nile tilapia juveniles, GIFT line

O objetivo deste estudo foi avaliar a ocorrência de resposta compensatória no desempenho produtivo de juvenis de tilápia do Nilo Oreochromis niloticus, linhagem GIFT, submetidos a diferentes estratégias alimentares. Foram utilizados 135 juvenis de tilápia, distribuídos em nove tanques de polietileno de 100L cada. As estratégias testadas foram: grupo controle (alimentado todo dia), grupo alimentado por cinco dias seguidos de dois dias de restrição de alimento (5A/2R) e grupo alimentado por quatro dias seguidos de três dias de restrição de alimento (4A/3R). Foram avaliados parâmetros físico-químicos da água e de desempenho produtivo. Os resultados foram submetidos à análise de variância, e as médias foram comparadas pelo teste Tukey, a 5 por cento de probabilidade. A qualidade de água, o fator de condição e a conversão alimentar não foram influenciados pela estratégia alimentar. O grupo alimentado com a estratégia 5A/2R apresentou peso final, ganho de peso e taxa de crescimento específico semelhantes ao grupo continuamente alimentado (7,8 e 9,2g; 6,4 e 7,8g e 2,7 e 3,0 por cento dia-1, para peso final, ganho de peso e taxa de crescimento especifico, respectivamente). A estratégia 4A/3R apresentou os piores resultados de desempenho produtivo, e a estratégia 5A/2R pode ser usada na alimentação de juvenis de tilápia do Nilo sem prejuízo ao desempenho produtivo, possibilitando inclusive redução de até 22,5 por cento na quantidade de alimento ofertada.

The objective of this study was to evaluate the occurrence of compensatory answer on productive performance of Nile tilapia Oreochromis niloticus juveniles, GIFT line, submitted to different feeding strategies. It was used 135 juveniles tilapias distributed in nine 100L polyethylene tanks each. The tested strategies were the control group (fed everyday), group fed for 5 days followed by 2 days of food restriction (5A/2R) and group fed for 4 days followed by 3 days of food restriction (4A/3R). Were evaluated physical chemical water parameters e growth performance. Results were submitted to an analysis of variance and averages compared by Tukey test 5 percent. Water quality, condition factor and feed conversion were not influenced by feeding strategy. Group fed 5A/2R strategy showed final weight, weight gain and specific growth rate similar to group continually fed (7.8 e 9.2g; 6.4 e 7.8g e 2.7 e 3.0 percent day-1, for final weight, weight gain and specific growth rate, respectively). The strategy 4A/3R showed the poorest productive performance. Strategy 5A/2R can be used in Nile tilapia juveniles feeding without damage to the fish productive performance, allowing a reduction of up to 22.5 percent on the feed quantity offered.

Desempenho de ratos em um esquema de DRL sob diferentes níveis de privação alimentar / Rats performance in a DRL scheme under different food deprivation levels

O esquema de reforçamento diferencial de baixas taxas (DRL) é amplamente utilizado em estudos de comportamentos relacionados à discriminação temporal. Porém, não está claro quais são os efeitos de diferentesníveis de privação em esquemas temporais, especialmente em DRL. O presente estudo testou a hipótese de queprivações mais severas prejudicariam o desempenho de sujeitos sob controle do DRL, comparado com os submetidos a privações mais brandas. Três grupos de ratos submetidos inicialmente a três diferentes níveis de privação alimentar (80, 90 e 100% do peso ad lib) foram treinados em DRL-20 s. Após o treino, realizou-se uma manipulação intra-grupos em duas condições sucessivas de teste: o grupo de privação 80% passou para 100% e o de 100% passou para 80%; o grupo 90% permaneceu nessa condição ao longo de todo o experimento como grupo-controle. Os animais apresentaram um pior desempenho na tarefa quando a transição da privação foi de 100% para 80% do peso ad lib e uma melhora de desempenho quando a transição foi de 80% para 100% ad lib. Não houve alteração de desempenho quando a transição foi de 90% para 100% ou para 80% ad lib. Os resultados indicam que o desempenho de ratos em uma tarefa de DRL é influenciado não só pelo estado gerado por um nível de privação alimentar específico, mas também por experiências de estados fisiológicos e cognitivos adquiridos em situações anteriores.

The scheme of differential reinforcement of low response rates (DRL) is largely employed in behavioral studies of temporal discrimination. However, it is not clear what the behavioral effects of different deprivation levels on the behavior under the control of temporal schemes of reinforcement are, especially the DRL. The present study tested the hypothesis that more severe deprivation disrupts the subjects' performance under DRL control, compared to that of subjects exposed lower levels of deprivation. Three groups of rats initially submitted tothree different food deprivation levels (80, 90 and 100% ad lib) were trained under a DRL-20 s scheme. After the training, deprivation was manipulated intra-group, in two consecutive testing conditions: the deprivation of the 80% group was changed to 100% ad lib and deprivation of the 100% group was changed to 80% ad lib; the 90% deprived group was kept under this level of deprivation across all experimental sessions as a controlgroup.The animals showed a worse performance in the DRL task when the deprivation transition went from 100% to 80% ad lib and a better performance when the transition was from 80% to 100% ad lib. There were no systematic changes in performance under the transitions from 90% to 100% or from 90% to 80% ad lib. The results indicate that the rats performance in a DRL is affected not only by the state generated by a specific level of food deprivation, but also by physiological and cognitive states acquired in preceding situations.

The Concept and Measurement of Food Security / 예방의학회지

OBJECTIVES: During the past two decades, food deprivation and hunger have been recognized to be not just the concerns of only underdeveloped or developing countries, but as problems for many affluent Western nations as well. Many countries have made numerous efforts to define and measure the extent of these problems. Based on these efforts, the theory and practice of food security studies has significantly evolved during the last decades. Thus, this study aims to provide a comprehensive review of the concept and measurement of food security. METHODS AND RESULTS: In this review, we introduce the definition and background of food security, we describe the impact of food insecurity on nutrition and health, we provide its measurements and operational instruments and we discuss its applications and implications. Some practical information for the use of the food security index in South Korea is also presented. CONCLUSIONS: Food security is an essential element in achieving a good nutritional and health status and it has an influence to reduce poverty. The information about the current understanding of food security can help scientists, policy makers and program practitioners conduct research and maintain outreach programs that address the issues of poverty and the promotion of food security.

Altered Regulation of Water Channels and Sodium Transporters in Fasting-induced Polyuria in Rat Kidney / 대한신장학회잡지

PURPOSE: Starvation causes impairment in the urinary concentration ability. However, the molecular basis for the impaired urinary concentration and polyuria remains undefined. We examined the effects of food deprivation on the water handling by the kidney and it's regulatory mechanism. METHODS: Sprague-Dawley rats were used. They were placed in metabolic cages and deprived of food but had free access to water for 24 hours. Control rats had free access to both water and food. Protein expression of aquaporin-2 (AQP2) and Na+-K+-2Cl- cotransporter (NKCC2) was determined in the kidney by Western blot analysis. Protein expression of type VI adenylyl cyclase and prostaglandin E2 synthase (PGES) was determined. Urinary PGE2 excretion was also determined by radioimmunoassay. RESULTS: Food deprivation (FD) resulted in impaired urinary concentration associated with decreased tubular water reabsorption and increased urine output. The expression of AQP2 proteins was significantly decreased in the inner stripe of the outer medulla (ISOM). The expression of NKCC2 was not affected in ISOM. The adenylyl cyclase VI expression was increased in ISOM in FD rats. The protein expression of PGES was decreased in the cortex/OSOM and ISOM. The 24 hr urinary excretion of PGE2 was significantly decreased in FD rats compared with controls. CONCLUSION: These findings indicate that FD-induced urinary concentration defect may related to a reduced abundance of AQP2 in the kidney. It is also suggested that the primary impairment in the pathway to the activation of AQP2 in food deprivation is independent of vasopressin/cAMP or prostaglandin activity.

Fasting-induced Down-regulation of NADPH-diaphorase in the Magnocellular PVN of Rats

In this study, we examined if glucocorticoids are required for the fasting-induced decrease of neuronal nitric oxide synthase (nNOS) in the magnocellular division of the paraventricular nucleus (PVN). Rats were adrenalectomized, subjected to 48 h of food deprivation with/without dexamethasone (5 mg/ kg, 4 subcutaneous injections with 12 h intervals), and the brain slices were processed for NADPH-diaphorase (NADPH- d) staining, a histochemical marker for nNOS in neuronal cells. In food deprived adrenalectomized rats, but not in free fed intact rats, dexamethasone significantly decreased NADPH-d staining in the magnocellular PVN. We previously reported that food deprivation decreases nNOS in the magnocellular PVN of intact rats. Thus, the present results together with our previous report suggest that although glucocorticoids are required for fasting-induced nNOS down-regulation in the magnocellular PVN, glucocorticoids may not be directly involved and some other molecular signals produced by food deprivation may play a pivotal role over glucocorticoid in the regulatory pathway for nNOS expression in this brain region.

Effect of ICV Corticosterone on hypothalamic NPY mRNA Expression in food-restricted, Adrenalectomized Rats / 대한내분비학회지

BACKGROUND: Adrenalectomy does impair the expression of hypothalamic NPY gene in the rat and replacement of glucocorticoid by intracerebroventricular(ICV) route resulted in a normalization of refeeding hyperphagia and weight gain in adrenalectomized(ADX), food-deprived rats. The purpose of this study was to assess the direct effect of CNS glucocorticoid on hypothalamic NPY gene expression which occurs following food deprivation in ADX rats. METHODS: Adult male Wistar rats were fitted with ICV cannulae and restricted the food intake for 14 days. Adrenalectomy and sham operation were done on the 10th day and single ICV corticosterone acetate(100ug/2uL) was given in one ADX group(ADX+CORT, n=9) and vehicle (2uL) was given in another ADX group(ADX+VEH, n=9) and sham rats(SHAM+VEH, n=7). After experiment, we measured NPY mRNA on arcuate nucleus by in situ hybridization. RESULTS: The rate of weight loss of ADX rats closely parallded that of sham-operated rats. Plasma glucose and insulin levels were not significantly different in three groups. Hybridization density on the ARC in ADX+VEH rats(0.42+/-0.02uCi/g: p<0.05) was significantly reduced compared to that in sham controls(0.68+/-0. 11uCi/g). ICV corticosterone injection increased the hybridization density in ADX+CORT rats(0.53+/-0.04uCi/g) compared to vehicle alone, although this did not reach that of controls. NPY gene expression was 40% in ADX+VEH rats and 62% in ADX+CORT rats compared to control rats. CONCLUSIONS: These results are consistent with the hypothesis that CNS glucocorticoid deficiency appears to be responsible for the impairment of refeeding hyperphagia in ADX rats and the effect of CNS glucocorticoid deficiency is a manifestation of impaired activation of hypothalamic NPY gene expression in the ARC.