Mutant K-ras oncogene regulates steroidogenesis of normal human adrenocortical cells by the RAF-MEK-MAPK pathway

The result of our previous study has shown that the K-ras mutant (pK568MRSV) transfected human adrenocortical cells can significantly increase cortisol production and independently cause cell transformation. The aim of this study is to investigate the effect of the active K-ras oncogene on the cortisol production in normal human adrenocortical cells. First we used isopropyl thiogalactoside to induce the inducible mutant K-ras expression plasmid, pK568MRSV, in the stable transfected human adrenocortical cells. The result showed that the increase of RasGTP levels in transfected cells was time-dependent after isopropyl thiogalactoside induction. Additionally, results from Western blot analysis revealed significant elevation in phosphorylation of c-Raf-1 and Mitogen-activated protein kinase. We also detected the levels of mRNA encoding Cholesterol side-chain cleavage enzyme (P450(SCC)), 17alpha-Hydroxylase/17,20-lyase (P450(c17)) and 3beta-Hydroxysteroid dehydrogenase (3betaHSD) were increased in human adrenocortical cells transfected with mutant K-ras after IPTG treatment. The increase of mRNA amount in P450(scc) P450(c17) and 3betaHSD and the elevation of cortisol level were inhibited with a pretreatment of PD098059, a specific extracellular signal-regulated kinase inhibitor. In our previous report, we proved that lovastatin, a pharmacological inhibitor of p21(ras) function, also reversed the increase of cortisol level in mutant K-ras stably transfected human adrenocortical cells. Taken together, these findings proved that the active mutant Ras enhanced not only cell proliferation but also steroidogenesis in steroidogenic phenotype cells by activating Raf-MEK-MAPK related signal transduction pathway. Therefore, we believe that K-ras mutants influence regulation of steroidogenesis in adrenocortical cells through RAF-MEK-MAPK pathway.     

Adrenocortical function and multiple organ failure in severe sepsis

BACKGROUND: Some patients with severe sepsis may have relative adrenocortical insufficiency, although not all studies confirm this finding. Corticosteroids play an important role in controlling excessive immune response, and they may reduce the severity of organ dysfunction in critical illness. In this prospective study, we investigated the incidence of adrenal insufficiency in severe sepsis and its relation to the development of multiple organ failure. METHODS: Forty-one patients meeting the criteria for severe sepsis were studied. A short ACTH stimulation test was carried out within 24 h of the diagnosis of sepsis. Peak serum cortisol level < 680 nmol/L and a rise of less than 260 nmol/L were used as the criteria for relative adrenocortical insufficiency. RESULTS: Relative adrenocortical insufficiency was detected in six patients. Duration of the ICU stay (P = 0.002) and mechanical ventilation (P = 0.024) were significantly longer in patients with impaired adrenal function. In the survivors, SOFA scores were significantly higher in patients with impaired adrenal function. The plasma ACTH levels were normal in most of the patients with relative adrenal insufficiency, whereas most patients with normal adrenal function had extremely low plasma ACTH levels. CONCLUSION: The ICU stay was longer and multiple organ failure more severe in patients with impaired adrenocortical function. There was a clear dissociation between ACTH and cortisol levels in AAR patients. This finding suggests that the integrity of the hypothalamic-pituitary-adrenal axis may be impaired in severe sepsis.     

Perioperative response of leptin and the tumor necrosis factor alpha system in morbidly obese patients. Influence of cortisol inhibition by etomidate

BACKGROUND: Leptin, tumor necrosis factor alpha (TNFalpha) and soluble TNFalpha receptors are secreted by the adipose tissue. Surgery induces a complex cytokine and neurohormonal response. The aim of our study was to investigate the perioperative response of leptin and the TNFalpha system in morbidly obese patients submitted to gastroplasty, and the possible involvement of cortisol in their responses. METHODS: Serum cortisol, adrenocorticotropic hormone (ACTH), leptin, TNFalpha and soluble TNFalpha receptor I were measured in 22 morbidly obese women (11 anesthetized with thiopental and 11 with etomidate, a well known inhibitor of cortisol synthesis). Samples were collected before anesthesia induction, just before surgical incision, and 2, 4, 6, 12, 24 and 48 h after the start of surgery. RESULTS: Baseline serum leptin correlated with body mass index (r=0.567, P=0.007). Baseline serum leptin and TNFalpha were higher than normal. Cortisol release was inhibited in the etomidate group with a subsequent higher stimulation of ACTH release. A statistically significant decrease in serum leptin levels was observed in both groups at 2, 4, 6 and 48 h, compared with basal values. A similar decrease in serum TNFalpha levels was observed in both groups, but the decrease reached significance only in the etomidate group. Serum soluble TNFalpha receptor I did not decrease. No differences were found between the two groups in leptin, TNFalpha or soluble TNFalpha receptor I concentrations at any time. CONCLUSION: Serum leptin and TNFalpha levels decrease in obese patients during gastroplasty. Transitory inhibition of cortisol release does not alter this response.     

糖尿病患者高血糖与皮质醇分泌状况的关系

目的研究糖尿病患者的皮质醇分泌状况,探讨其与高血糖之间的关系。方法139例糖尿病患者(糖尿病组)行口服糖耐量试验(OGTT),计算胰岛素敏感指数(ISI)、HOMA指数(HOMAIR)、葡萄糖及胰岛素曲线下面积(AUCg,AUCi);同时检测患者血、尿皮质醇,以及血促肾上腺皮质激素(ACTH)等分泌情况。以52例非糖尿病健康者作为对照(对照组)。结果糖尿病组中高皮质醇分泌患者所占比例显著高于对照组(25.2%vs11.5%)(P<0.05)。糖尿病组08:00血皮质醇、16:00血皮质醇、日平均血皮质醇及尿游离皮质醇检测值均显著高于对照组(P<0.05)。糖尿病组中,伴高皮质醇分泌患者的空腹血糖(FPG)、糖负荷2h后血糖(2hPPG)、AUCg及HOMAIR均明显高于皮质醇正常分泌患者(P<0.05)。剔除性别、年龄、体质量指数及腰围的影响,FPG、2hPPG、AUCg、ISI及HOMAIR等与血、尿皮质醇水平相关。结论糖尿病患者高皮质醇分泌的患病率升高,其血糖升高与高皮质醇分泌互为因果。     

Temporal and individual variations in the dose of glucocorticoid used for the treatment of salt-losing congenital virilizing adrenal hyperplasia due to 21-hydroxylase deficiency

The dose of glucocorticoid was evaluated in the treatment of 19 patients with salt-losing congenital adrenal hyperplasia due to complete or nearly complete 21-hydroxylase deficiency. In most cases, follow-up was from infancy to puberty. The dose of steroid was expressed as oral cortisol (mg/m² body surface area 124 hours); the equivalent doses of the various glucocorticoid preparations was as follows: 100 mg oral cortisol = 120 mg oral cortisone acetate = 25 mg oral prednisone = 50 mg intramuscular cortisol = 60 mg intramuscular cortisone acetate. The dose of glucocorticoid producing good laboratory and clinical control varied significantly with age. The dose fell from 26 mg/m²/24 hours in early infancy to 19 mg/m²/24 hours between 6 and 8 years of age, and then rose to 23–24 mglm²/hour in adolescence. In addition to these age-related changes, there were large individual variations at each age. Indeed, the values from 4 of the 19 patients were not included in the calculation of the mean because they were more than 3 SD either above or below the mean. For the rest of the patients, the coefficient of variation ranged from 14.5% to 37.2%. It is concluded that glucocorticoid therapy must be adjusted carefully to the age and needs of each patient.     

Über den Einfluß von Glucose auf den Umsatz von l-Tryptophan beim Säugling

Zusammenfassung Es wird der Einfluß parenteral verabfolgter Glucose auf den Umsatz von l-Tryptophan beim Säugling untersucht. Höhere Glucosedosen rufen eine Verlängerung der biologischen Halbwertzeit hervor bei gleichzeitiger Abnahme des Transfer. Dabei ist die Rate der Elimination von l-Tryptophan von der Höhe der zugeführten Glucosedosis abhängig. Es besteht jedoch weder eine positive noch negative Korrelation zur Höhe des Cortisolspiegels im Plasma. Die für die Änderung der kinetischen Werte in Betracht kommenden Ursachen werden diskutiert.

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The effect of glucose on the turnover of l-tryptophan in infants

The influence of intravenous administered glucose on the turnover of l-tryptophan in infants has been studied. High doses of glucose cause a prolongation of the biological half-life with simultaneous reduction of the transfer. Moreover, the rate of elimination of l-tryptophan is dependent upon the dose of glucose administered. However, there is neither a positive nor a negative correlation with the plasma level of cortisol. The factors which influence the kinetic values are discussed.

Die Ergebnisse sind Teile der Dissertation von Herrn Spangenberg.     

支气管哮喘患者外周血白细胞糖皮质激素受体的改变

应用放射配体结合法和放射免疫法分别检测了１７例哮喘患发作期外周血白细胞糖皮质激素受体（ＧＲ）和血浆皮质醇（Ｆ）。结果：外周血白细胞ＧＲ最大结合容量（Ｒ０）为１２９０８±２５０１位点／细胞，与健康对照组比较无显差异（Ｐ＞０．０５）。ＧＲ平衡解离常数（Ｋｄ）为１６．５４±５．３６ｎｍｏｌ／Ｌ，明显高于对照组（Ｐ＜０．０１）。血浆Ｆ为４３２±２７５ｎｍｏｌ／Ｌ，与对照组比较无显差异（Ｐ＞０．０５）     

Lack of effect of desmopressin on ACTH and cortisol responses to ovine corticotropin-releasing hormone in anorexia nervosa

Abstract. Both arginine vasopressin (AVP) and corticotropin-releasing hormone (CRH) are involved in the release of ACTH in man. Desmopressin (DDAVP), a synthetic analogue of AVP, has been shown to have a CRH-like action (able to promote ACTH and cortisol release) in animals but not in normal man. Nevertheless, DDAVP is able to release ACTH and cortisol in ACTH-dependent Cushing's disease. We studied eight anorexia nervosa (AN) patients [as AN is a condition in which chronic activation of the hypothalamic-pituitary-adrenal (HPA) axis is commonly reported] in a refeeding phase of the disease, to evaluate whether, after weight gain, ACTH and cortisol response to ovine corticotropin-releasing hormone (oCRH) [1 μg kg^-1 body weight (BW) i.v.] is restored. We also wanted to ascertain the effect on the HPA axis of 10 μg i.v. DDAVP alone and as pretreatment to oCRH (1 μg kg^-1 BW i.v.)-induced secretion of ACTH and cortisol. We studied six normal women as control subjects. No significant differences in ACTH and cortisol responses to oCRH were found between AN patients and control subjects. DDAVP was not able to stimulate ACTH or cortisol release in AN patients or in control subjects, but in the latter it was able to significantly enhance (P < 0.05) ACTH [area under curve (AUC): 590.0± 104.4 pmol L^-1 120 min^-1 and cortisol (AUC: 28899.0 ± 6935.2nmol L^-1 120 min^-1) responses to oCRH (ACTH AUC: 325.7 ± 101.7 pmol L^-1 120 min^-1, cortisol AUC: 14197.4 ± 2930.0 nmol L^-1 120 min^-1). The present data show that DDAVP does not stimulate ACTH and cortisol in AN patients or, as previously reported, in normal subjects. However, DDAVP is able to enhance ACTH and cortisol release after oCRH administration in normal subjects but not in AN patients. This finding could be due to a down-regulation of hypophyseal DDAVP V3 receptors in AN as a direct consequence of the hypercortisolaemic status usually present.     

Influence of meptazinol on metabolic and hormonal responses following major surgery

Opioid drugs in high doses can obtund the stress response to major surgery but only at the expense of marked cardiorespiratory depression. The postoperative hormonal response to surgical stress was measured in 20 patients undergoing hysterectomy who were given either meptazinol 100 mg or morphine 15 mg intramuscularly at the end of the surgery. Both drugs at the doses used failed to diminish the stress response. Those patients who received meptazinol showed elevated prolactin levels: this may be an indicator of agonist activity at the mu 1 opioid receptor.