Induction of L-lysine-2-oxoglutarate reductase by glucagon and glucocorticoid in developing and adult rats in vivo and in vitro studies

L-Lysine-2-oxoglutarate reductase (EC 1.5.1.8, NADP⁺) in the liver of adult rats increased 4–5-times when the animals were treated with alloxan. In diabetic rats injection of insulin or adrenalectomy prevented the increase in enzyme activity. The activity of the similar enzyme in kidney was not changed by these treatments. The enzyme activity in primary cultured adult rat hepatocytes was also induced by addition of dexamethasone and glucagon together, and glucagon could be replaced by dibutyryl cyclic AMP. Insulin inhibited the induction. The hormonal induction was also inhibited by actinomycin D and by cycloheximide. During development of rats, fetal liver showed very low activity, but the activity appeared on day 1 after birth and then increased rapidly, reaching the adult level by day 5. The activity of the kidney enzyme increased more slowly and reached the adult level 1 month after birth. Intra-uterine injection of glucagon caused precocious induction of the liver enzyme in fetuses. These results indicate that the activity of L-lysine-2-oxoglutarate reductase in the adult liver and in part in neonatal liver also, is controlled by both glucagon and glucocorticoid.     

Autoradiographic studies of a glucocorticoid agonist and antagonist: Localization of 3H-corticosterone and 3H-cortexolone in mouse brain

Summary The localization in the mouse brain of corticosterone, the natural glucocorticoid in the mouse, and cortexolone, reported to be a glucocorticoid antagonist, was studied by autoradiography 30 min after in vivo administration of the tritiated compounds.After ³H-corticosterone (³HB) injection, radioactivity was preferentially concentrated in cell nuclei of several structures within the limbic system, and in nuclei of certain neurones of the cerebral cortex and medulla oblongata. This nuclear concentration was abolished after injection of ³H-corticosterone with an excess of unlabelled corticosterone. After ³H-cortexolone (³HS) injection, a diffuse radioactivity was observed throughout the brain. However, a higher concentration of grains was present in the ventral nucleus arcuatus and in the infundibulum. When excess unlabelled cortexolone was administered with ³H-cortexolone this preferential accumulation of grains was abolished.The accumulation of ³H-cortexolone in the medial basal hypothalamic region suggests that cortexolone concentrates preferentially in dexamethasone (DM) target regions, and in addition the autoradiographic results show that the cortexolone-receptor complex does not accumulate in the cell nucleus.

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Résumé La localisation au niveau du cerveau de souris de la corticostérone, qui est le glucocorticoide naturel chez la souris, et de la cortexolone, démontrée comme étant un antagoniste des glucocorticoides, est étudiée par autoradiographie 30 min après injection in vivo des composés tritiés.Après injection de ³H-corticosterone (³HB), la radioactivité se concentre préférentiellement dans des noyaux cellulaires de plusieurs structures du système limbique et dans les noyaux de certains neurones du cortex cérébral et du bulbe rachidien. Cette concentration nucléaire est abolie après injection de ³H-corticostérone en présence d'un excès de corticostérone non radioactive. Après injection de ³H-cortexolone (³HS), une distribution diffuse de la radioactivité est observée dans tout le cerveau, cependant, une concentration plus élevée de grains d'argent est présente dans la partie ventrale du nucleus arcuatus et dans l'infundibulum. Après injection de ³H-cortexolone en présence d'un excès de cortexolone non radioactive, cette accumulation préférentielle des grains est abolie.L'accumulation de la ³H-cortexolone dans la région hypothalamique suggère que la cortexolone se concentre préférentiellement dans la région cérébrale qui contient les sites de liaison de la dexaméthasone et de plus, les résultats autoradiographiques montrent que le complexe cortexolone-récepteur ne s'accumule pas dans le noyau cellulaire.

     

Autoradiographic localization of 3H-glucocorticoids and 3H-cortexolone in mouse pituitary

Summary Autoradiograms of mouse pituitaries were prepared 30 min after injection of ³H-dexamethasone (³HDM), ³H-corticosterone (³HB) and ³H cortexolone (³HS) either alone or in the presence of competing unlabelled steroids. ³H-dexamethasone accumulated in cell nuclei of both the pars distalis and the pars nervosa but not in those of the pars intermedia. This preferential accumulation (nuclear/cytoplasmic grain density, 41) was abolished by the concurrent administration of excess dexamethasone. ³H-corticosterone, to a much less marked extent than ³H-dexamethasone, accumulated in cell nuclei of the pars distalis but not in those of the pars intermedia and the pars nervosa. Excess unlabelled corticosterone diminished nuclear grain density in the pars distalis. After ³H-cortexolone injection, preferential nuclear uptake was not observed. In a second series of experiments, excess dexamethasone (10 x, 100 x), corticosterone (100 x, 300 x) and cortexolone (100 x, 300 x) administered with ³H-dexamethasone were without effect on cytoplasmic grain density but totally abolished preferential nuclear accumulation. Parallel biochemical studies on kidney cytoplasmic preparations from the same animals showed no differences in total cytoplasmic radioactivity between treatments but marked differences in cytoplasmic bound ³H-dexamethasone. The results demonstrate: i) that dexamethasone binds specifically to cell nuclei of the pars distalis and the pars nervosa and that this nuclear concentration is abolished by competing corticosterone and cortexolone as well as dexamethasone; ii) that corticosterone localizes in cell nuclei of the pars distalis but much less markedly than dexamethasone; iii) that cortexolone fullfils the criteria of a glucocorticoid antagonist at the pituitary cell level.

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Résumé La localisation au niveau de l'hypophyse de souris de la ³H-dexaméthasone (³HDM), de la ³H-corticostérone (³HB) et de la ³H-cortexolone (³HS) est étudiée par autoradiographie 30 min après l'injection des composés tritiés seuls ou en présence de stéroides compétiteurs non radioactifs. La ³H-dexaméthasone s'accumule dans des noyaux cellulaires de la pars distalis et de la pars nervosa mais pas dans des noyaux de la pars intermédia. Cette accumulation préférentielle (densité des grains d'argent nucléaire/cytoplasmique: 4/1) est abolie par l'injection de ³H-dexaméthasone en présence de dexaméthasone non radioactive. La ³H-corticostérone se concentre avec une intensité beaucoup plus faible que la ³H-dexaméthasone uniquement dans certains noyaux de la pars distalis. Un excès de corticostérone non radioactive diminue la densité nucléaire des grains d'argent des cellules de la pars distalis. Après injection de ³H-cortexolone, aucune accumulation préférentielle de grains d'argent n'est observée dans les noyaux cellulaires. Dans une seconde série d'expériences, la ³H-dexaméthasone est injectée soit en présence d'excès de dexaméthasone (10x, 100x) ou de corticostérone (100x, 300x) ou de cortexolone (100 x, 300 x). Dans ces conditions, la densité cytoplasmique des grains d'argent n'est pas différente de celle observée après injection de ³H-dexaméthasone seule mais l'accumulation préférentielle de la radioactivité dans les noyaux cellulaires est abolie. Des études biochimiques parallèles effectuées sur des préparations cytoplasmiques de rein des mêmes animaux montrent que la radioactivité cytoplasmique totale ne varie pas tandis que la liaison cytoplasmique de la ³H-dexaméthasone diffère suivant les traitements. Ces résultats montrent i) que la dexaméthasone se fixe spécifiquement dans des noyaux cellulaires de la pars distalis et de la pars nervosa et que cette fixation nucléaire est abolie aussi bien par des excés de corticostérone ou de cortexolone que par des excès de dexaméthasone, ii) que la corticostérone se localise dans des noyaux cellulaires de la pars distalis mais beaucoup moins intensément que la dexaméthasone, iii) que la cortexolone se comporte comme un antagoniste des glucocorticoides au niveau de la cellule hypophysaire.

     

Cortisol promotes stress tolerance via DAF-16 in Caenorhabditis elegans

In this study, we studied the effects of cortisol and cortisone on the age-related decrease in locomotion in the nematode Caenorhabditis elegans and on the tolerance to heat stress at 35 °C and to oxidative stress induced by the exposure to 0.1% H₂O₂. Changes in mRNA expression levels of C. elegans genes related to stress tolerance were also analyzed. Cortisol treatment restored nematode movement following heat stress and increased viability under oxidative stress, but also shortened worm lifespan. Cortisone, a cortisol precursor, also restored movement after heat stress. Additionally, cortisol treatment increased mRNA expression of the hsp-12.6 and sod-3 genes. Furthermore, cortisol treatment failed to restore movement of daf-16-deficient mutants after heat stress, whereas cortisone failed to restore the movement of dhs-30-deficient mutants after heat stress. In conclusion, the results suggested that cortisol promoted stress tolerance via DAF-16 but shortened the lifespan, whereas cortisone promoted stress tolerance via DHS-30.     

Blockage of glucocorticoid receptors during memory acquisition, retrieval and reconsolidation prevents the expression of morphine-induced conditioned place preferences in mice

Association between the reward caused by consuming drugs and the context in which they are consumed is essential in the formation of morphine-induced conditioned place preference (CPP). Glucocorticoid receptor (GRs) activation in different regions of the brain affects reward-based reinforcement and memory processing. A wide array of studies have demonstrated that blockage of GRs in some brain areas can have an effect on reward-related memory; however, to date there have been no systematic studies about the involvement of glucocorticoids (GCs) in morphine-related reward memory. Here, we used the GR antagonist RU38486 to investigate how GRs blockage affects the sensitization and CPP behavior during different phases of reward memory included acquisition, retrieval and reconsolidation. Interestingly, our results showed RU38486 has the ability to impair the acquisition, retrieval and reconsolidation of reward-based memory in CPP and sensitization behavior. But RU38486 by itself cannot induce CPP or conditioned place aversion (CPA) behavior. Our data provide a much more complete picture of the potential effects that glucocorticoids have on the reward memory of different phases and inhibit the sensitization behavior.     

小剂量糖皮质激素联合消炎痛治疗亚急性甲状腺炎的临床效果

目的:探讨小剂量糖皮质激素联合消炎痛治疗亚急性甲状腺炎(Subacute thyroiditis,ST)的临床效果及安全性。方法:选取我院内分泌科2012年6月-2014年7月收治的150例亚急性甲状腺炎患者,按照随机平均原则即药物治疗的不同将其分为三组,每组50例,即泼尼松与消炎痛联合治疗(A组)、泼尼松单独治疗(B组)、消炎痛单独治疗(C组),对比并分析三组的治疗效果,包括甲状腺疼痛和肿大平均消失时间,治疗1周的ESR平均水平,治疗4周后的血清TSH、FT3、FT4水平,并通过随访,观察治疗后8周患者不良反应的发生率、复发率。结果:(1)A组患者甲状腺疼痛和甲状腺肿大的消失时间与B组比较无显著差异(P0.05),A、B组均显著短于C组(P0.05)。A组患者治疗后1周、4周的ESR水平与B组对比差异不明显,无统计学意义(P0.05);A、B组患者治疗后1周的ESR水平明显低于C组(P0.05)。A、B组治疗后的血清TSH、FT3、FT4水平改善程度均优于C组,差异有统计学意义(P0.05)。(2)A组、C组的不良反应发生率、复发率均低于B组,差异具有统计学意义(P0.05)。结论:采用小剂量糖皮质激素联合消炎痛治疗亚急性甲状腺炎的临床效果显著,且不良反应和复发情况少。     

Dexamethasone suppresses osteogenesis of osteoblast via the PI3K/Akt signaling pathway in vitro and in vivo

The hypofunction of osteoblasts induced by glucocorticoids (GCs) has been identified as a major contributing factor for GC-induced osteoporosis (GIO). However, the biological mechanism underlying the effect of GC in osteoblasts are not fully elucidated. Recent studies implicated an important role of phosphoinositide 3-kinase (PI3K)/protein kinase B(Akt) signaling pathway in the regulation of bone growth. We propose that the PI3K/Akt signaling may be implicated in the process of GC-induced osteogenic inhibition in osteoblasts. In this study, primary osteoblasts were used in vitro and in rats in vivo to evaluate the biological significance of the PI3K/Akt pathway in GC-induced bone loss. In vivo, dexamethasone (Dex)-treated rats had low bone mineral density and decreased expression levels of alkaline phosphatase (ALP), osteocalcin (OCN), and phosphorylated Akt (p-Akt) in bone tissue. In vitro study shows that Dex over the dose of 10^–8 M remarkably inhibited cellular osteogenesis, as represented by decreased cell viability, lessened ALP activity, and suppressed osteogenic protein expressions including ALP and OCN. Meanwhile, a dramatic downregulation in the PI3K/Akt pathway phosphorylation was also observed in Dex-treated osteoblasts. These changes were marked rescued by treatment with a PI3K agonist 740Y-P. Moreover, downregulation of ALP and OCN expressions by LY294002 can mimic the suppressive effects of Dex. These data together reveal that the suppressed PI3K/Akt pathway is involved in the regulatory action of Dex on osteogenesis.     

小剂量糖皮质激素联合持续性血液净化治疗儿童严重脓毒症的效果及安全性研究

摘要 目的：分析小剂量糖皮质激素联合持续性血液净化治疗儿童严重脓毒症的效果及安全性。方法：选择自2021年1月至2023年1月接诊的102例儿童严重脓毒症患儿作为研究对象,随机分为对照组和观察组,各51例;对照组予以经典治疗方案,观察组在对照组的基础上,予以小剂量糖皮质激素联合持续性血液净化治疗;记录两组治疗后各项信息,比较两组治疗前后外周血乳酸、中心静脉血氧饱和度（ScvO₂）、血清炎症指标、PCIS评分、APACHE Ⅱ评分,观察主要并发症发生情况。结果：与对照组相比,观察组机械通气、低血压持续及入住ICU等时间较短,7 d内停升压药率较高（P＜0.05）;两组28 d病死率比较无差异（P＞0.05）;观察组治疗后乳酸、降钙素原（PCT）、肿瘤坏死因子-α（TNF-α）、白介素-6（IL-6）水平均较对照组低,ScvO₂水平较对照组高（P＜0.05）;观察组治疗后PCIS评分较对照组高,APACHE Ⅱ评分较对照组低（P＜0.05）;观察组主要并发症发生率低于对照组（P＜0.05）。结论：小剂量糖皮质激素联合持续性血液净化治疗有利于儿童严重脓毒症患儿病情转归,减少主要并发症发生,可能与阻断炎症反应有关,值得进一步研究应用。