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1.
Int J Surg Case Rep ; 110: 108742, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37657383

RESUMO

INTRODUCTION: Vaginal stones are a rare pathology, with no clear guidelines on management and optimal removal techniques. PRESENTATION OF CASE: We report a novel surgical technique, leading to safe transvaginal extraction of the largest reported impacted vaginal stone. In this case we removed an 11 cm struvite stone transvaginally from a 46 year old patient. This was achieved by hollowing it out with surgical drills, allowing safe collapse of the outer cortex and complete removal. DISCUSSION: Our technique allowed for the safe, minimally invasive removal of the largest stone to be reported so far in the literature, preventing further complications for the patient. A full description of our technique is outlined to allow other clinicians utilisation of this for similar cases in the future. CONCLUSION: Future vaginal calculi could be managed using this technique, preventing the need for laparotomy or vaginal trauma.

2.
G Ital Med Lav Ergon ; 34(3 Suppl): 635-7, 2012.
Artigo em Italiano | MEDLINE | ID: mdl-23405737

RESUMO

Our research describes a medical surveillance, not included in usual Occupational Health activities, carried out in last year among Red Cross Volunteers active in Monza e Brianza Provincial Committee. This medical surveillance has been managed according to internal rules of Red Cross and national specific Laws. We report data concerning medical examination of 1285 volunteers, their consequences on their voluntary activities, problems arisen during and after medical controls. Starting from results of our medical controls, we evaluated legal and organizational possibilities of evolution of medical surveillance of Red Cross Volunteers specifically and more generally of Civil Protection Volunteers, considering specific new law recently promulgated which seem partially not homogeneous with 81/08 Decree.


Assuntos
Saúde Ocupacional/legislação & jurisprudência , Vigilância da População , Cruz Vermelha , Voluntários/legislação & jurisprudência , Voluntários/organização & administração , Humanos , Itália
3.
J Physiol Biochem ; 65(4): 329-37, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20358345

RESUMO

11 beta-hydroxysteroid dehydrogenase (HSDs) enzymes regulate the activity of glucocorticoids in target organs. HSD1, one of the two existing isoforms, locates mainly in CNS, liver and adipose tissue. HSD1 is involved in the pathogenesis of diseases such as obesity, insulin resistance, arterial hypertension and the Metabolic Syndrome. The stress produced by HCl overload triggers metabolic acidosis and increases liver HSD1 activity associated with increased phosphoenolpyruvate carboxykinase, a regulatory enzyme of gluconeogenesis that is activated by glucocorticoids, with increased glycaemia and glycogen breakdown. The aim of this study was to analyze whether the metabolic modifications triggered by HCl stress are due to increased liver HSD1 activity. Glycyrrhetinic acid, a potent HDS inhibitor, was administered subcutaneously (20 mg/ml) to stressed and unstressed four months old maleSprague Dawley rats to investigate changes in liver HSD1, phosphoenolpyruvate carboxykinase (PECPK) and glycogen phosphorylase activities and plasma glucose levels. It was observed that all these parameters increased in stressed animals, but that treatment with glycyrrhetinic acid significantly reduced their levels. In conclusion, our results demonstrate the involvement of HSD1 in stress induced carbohydrate disturbances and could contribute to the impact of HSD1 inhibitors on carbohydrate metabolism and its relevance in the study of Metabolic Syndrome Disorder and non insulin-dependent diabetes mellitus.


Assuntos
11-beta-Hidroxiesteroide Desidrogenases/biossíntese , 11-beta-Hidroxiesteroide Desidrogenases/fisiologia , Glucose/metabolismo , Fígado/enzimologia , Tecido Adiposo/metabolismo , Animais , Metabolismo dos Carboidratos , Carboidratos/química , Sistema Nervoso Central/embriologia , Ácido Glicirretínico/metabolismo , Fígado/metabolismo , Masculino , Modelos Biológicos , Fosfoenolpiruvato Carboxiquinase (ATP)/metabolismo , Isoformas de Proteínas , Ratos , Ratos Sprague-Dawley
4.
Life Sci ; 64(24): 2285-90, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10374918

RESUMO

The enzyme 11betaHSD2 protects the non-selective mineralocorticoid receptor from occupation by glucocorticoids in aldosterone target tissues. We studied the effect of stress elicited by intubation with a rubber catheter and administration of 10 ml of 0.45% NaCl (G3), of 10 ml of 200 mM HCl (G4) or intubation alone (G2) on the kinetics of the renal enzyme compared with untreated rats (G1). Microsomes were incubated with increasing masses of 3H corticosterone and 400 microM NAD at pH=7.4 during 5 minutes. Samples were extracted with ethyl acetate and analyzed by TLC. Results for n=4: Vmax for G1, 4.82 +/- 0.67. G2, 10.04 +/- 0.16***. G3, 9.16 +/- 0.74**. G4, 10.19 +/- 0.79*** pmoles/min/mg prot. Km for G1, 22.37 +/- 2.42. G2, 50.72 +/- 7.05*. G3, 55.25 +/- 8.37**. G4, 27.40 +/- 3.20 nM. (***p<0.001, **p<0.01 and *p<0.05 vs G1). All treatments increased Vmax. Intubation alone and gavage with 0.45% NaCl, but not with 200 mM HCl, increased Km. Taking together, the results could reflect a way to prevent occupation of type I receptors by increased levels of circulating glucocorticoids due to stressful situations. This protection seems more efficient under acidotic conditions causing--in addition to an increased Vmax--a low Km for the enzyme.


Assuntos
Hidroxiesteroide Desidrogenases/metabolismo , Isoenzimas/metabolismo , Rim/enzimologia , Estresse Fisiológico/enzimologia , 11-beta-Hidroxiesteroide Desidrogenases , Acidose/metabolismo , Animais , Corticosterona/metabolismo , Glucocorticoides/metabolismo , Rim/metabolismo , Cinética , Masculino , Microssomos/metabolismo , Ratos , Ratos Sprague-Dawley , Receptores de Mineralocorticoides/metabolismo , Estresse Fisiológico/metabolismo
5.
Braz J Med Biol Res ; 30(4): 479-86, 1997 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-9251768

RESUMO

The present paper reviews work from our laboratories evaluating the importance of adrenal cortical hormones in acidification by proximal and cortical distal tubules. Proximal acidification was determined by stationary microperfusion, and measurement of bicarbonate reabsorption using luminal pH determination was performed with H(+)-ionsensitive microelectrodes. Rats were adrenalectomized (ADX) 48 h before the experiments, and corticosteroids (aldosterone (A), corticosterone (B), and 18-OH corticosterone (18-OH-B)) were injected intramuscularly 100 and 40 min before the experiments. In ADX rats stationary pH increased significantly to 7.03 as compared to sham-operated rats (6.78). Bicarbonate reabsorption decreased from 2.65 +/- 0.18 in sham-operated rats to 0.50 +/- 0.07 nmol cm-2 s-1 after ADX. The administration of the three hormones stimulated proximal tubule acidification, reaching, however, only 47.2% of the sham values in aldosterone-treated rats. Distal nephron acidification was studied by measuring urine minus blood pCO2 differences (U-B pCO2) in bicarbonate-loaded rats treated as above. This pCO2 difference is used as a measure of the distal nephron ability to secrete H+ ions into an alkaline urine. U-B pCO2 decreased significantly from 39.9 +/- 1.26 to 11.9 +/- 1.99 mmHg in ADX rats. When corticosteroids were given to ADX rats before the experiment, U-B pCO2 increased significantly, but reached control levels only when aldosterone (two 3-microgram doses per rat) plus corticosterone (220 micrograms) were given together. In order to control for the effect of aldosterone on distal transepithelial potential difference one group of rats was treated with amiloride, which blocks distal sodium channels. Amiloride-treated rats still showed a significant reduction in U-B pCO2 after ADX. Only corticosterone and 18-OH-B but not aldosterone increased U-B pCO2 back to the levels of sham-operated rats. These results show that corticosteroids stimulate renal tubule acidification both in proximal and distal nephrons and provide some clues about the mechanism of action of these steroids.


Assuntos
Aldosterona/metabolismo , Corticosterona/metabolismo , Néfrons/metabolismo , Corticosteroides/fisiologia , Adrenalectomia , Animais , Bicarbonatos/metabolismo , Pressão Sanguínea/fisiologia , Potássio/metabolismo , Ratos , Ratos Wistar , Sódio/metabolismo
6.
Braz J Med Biol Res ; 25(5): 457-65, 1992.
Artigo em Inglês | MEDLINE | ID: mdl-1342221

RESUMO

1. Studies were carried out to determine the effect of intra-dermal injections of recombinant human interferon-gamma (rIFN gamma) on the viability of Mycobacterium leprae. Twenty-three untreated and 4 treated multibacillary patients, 12 with lepromatous leprosy (LL) and 15 with borderline lepromatous leprosy (BL), were selected for intradermal administration of rIFN gamma or PPD. Treated patients (LL and BL) had received multi-drug therapy according to the recommendations of the World Health Organization, i.e., rifampicin (600 mg/month), dapsone (100 mg/day) and clofazimine (50 mg/day and 300 mg/month) for 1-4 months. Three daily doses of 10 or 30 micrograms rIFN gamma induced local induration and mononuclear leucocyte accumulation. Bacteria isolated from a punch biopsy of the site 21 days after lymphokine administration were injected into mouse foot pads and evaluated for viability and growth. 2. The local response to rIFN gamma (specific activity 2 x 10(7) units/mg protein) induced a delay or total inhibition of M. leprae growth in the mouse foot pad, indicating that the cellular response to the antigen reduced local M. leprae viability. The extent of reduction in viability depended on the dose of rIFN gamma injected and the extent of local induration induced by the lymphokine. With a vigorous cell-mediated immune response growth was fully inhibited. 3. A similar but less extensive effect on M. leprae viability was observed in response to the local injection of 5 units in 0.1 ml of purified protein derivative of tuberculin (PPD).


Assuntos
Interferon gama/uso terapêutico , Hanseníase Virchowiana/terapia , Mycobacterium leprae/efeitos dos fármacos , Pele/efeitos dos fármacos , Pele/imunologia , Animais , Bioensaio , Quimioterapia Combinada , Humanos , Imunidade Celular/efeitos dos fármacos , Hanseníase Dimorfa/imunologia , Hanseníase Dimorfa/microbiologia , Hanseníase Dimorfa/terapia , Hanseníase Virchowiana/imunologia , Hanseníase Virchowiana/microbiologia , Camundongos , Camundongos Endogâmicos BALB C , Mycobacterium leprae/isolamento & purificação , Mycobacterium leprae/patogenicidade , Proteínas Recombinantes , Fatores de Tempo
7.
Med Cutan Ibero Lat Am ; 17(2): 103-4, 1989.
Artigo em Português | MEDLINE | ID: mdl-2666794

RESUMO

Report on a case of dapsone resistance in a BL patient with clinical diagnosis and laboratory confirmation. The resistance appeared after 17 years of dapsone treatment, and the laboratory tests revealed total resistance to all the tested dapsone concentrations. The case reported occurred in the city of Rio de Janeiro (Brazil) which presents a leprosy prevalence of 1.79/1,000.


Assuntos
Dapsona/farmacologia , Hanseníase Dimorfa/tratamento farmacológico , Mycobacterium leprae/efeitos dos fármacos , Idoso , Idoso de 80 Anos ou mais , Animais , Brasil , Dapsona/uso terapêutico , Resistência Microbiana a Medicamentos , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C
8.
Braz J Med Biol Res ; 43(1): 52-6, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20027486

RESUMO

Aldosterone concentrations vary in advanced chronic renal failure (CRF). The isozyme 11beta-hydroxysteroid dehydrogenase 2 (11beta-HSD2), which confers aldosterone specificity for mineralocorticoid receptors in distal tubules and collecting ducts, has been reported to be decreased or normal in patients with renal diseases. Our objective was to determine the role of aldosterone and 11beta-HSD2 renal microsome activity, normalized for glomerular filtration rate (GFR), in maintaining K+ homeostasis in 5/6 nephrectomized rats. Male Wistar rats weighing 180-220 g at the beginning of the study were used. Rats with experimental CRF obtained by 5/6 nephrectomy (N = 9) and sham rats (N = 10) were maintained for 4 months. Systolic blood pressure and plasma creatinine (Pcr) concentration were measured at the end of the experiment. Sodium and potassium excretion and GFR were evaluated before and after spironolactone administration (10 mg.kg-1.day-1 for 7 days) and 11beta-HSD2 activity on renal microsomes was determined. Systolic blood pressure (means +/- SEM; Sham = 105 +/- 8 and CRF = 149 +/- 10 mmHg) and Pcr (Sham = 0.42 +/- 0.03 and CRF = 2.53 +/- 0.26 mg/dL) were higher (P < 0.05) while GFR (Sham = 1.46 +/- 0.26 and CRF = 0.61 +/- 0.06 mL/min) was lower (P < 0.05) in CRF, and plasma aldosterone (Pald) was the same in the two groups. Urinary sodium and potassium excretion was similar in the two groups under basal conditions but, after spironolactone treatment, only potassium excretion was decreased in CRF rats (sham = 0.95 +/- 0.090 (before) vs 0.89 +/- 0.09 microEq/min (after) and CRF = 1.05 +/- 0.05 (before) vs 0.37 +/- 0.07 microEq/min (after); P < 0.05). 11beta-HSD2 activity on renal microsomes was lower in CRF rats (sham = 0.807 +/- 0.09 and CRF = 0.217 +/- 0.07 nmol.min-1.mg protein-1; P < 0.05), although when normalized for mL GFR it was similar in both groups. We conclude that K+ homeostasis is maintained during CRF development despite normal Pald levels. This adaptation may be mediated by renal 11beta-HSD2 activity, which, when normalized for GFR, became similar to that of control rats, suggesting that mineralocorticoid receptors maintain their aldosterone selectivity.


Assuntos
11-beta-Hidroxiesteroide Desidrogenase Tipo 2/fisiologia , Homeostase/fisiologia , Falência Renal Crônica/metabolismo , Microssomos/enzimologia , Potássio/metabolismo , 11-beta-Hidroxiesteroide Desidrogenase Tipo 2/metabolismo , Aldosterona/sangue , Animais , Pressão Sanguínea/fisiologia , Falência Renal Crônica/enzimologia , Masculino , Nefrectomia , Ratos , Ratos Wistar
10.
Braz. j. med. biol. res ; 43(1): 52-56, Jan. 2010. tab, ilus
Artigo em Inglês | LILACS | ID: lil-535636

RESUMO

Aldosterone concentrations vary in advanced chronic renal failure (CRF). The isozyme 11â-hydroxysteroid dehydrogenase 2 (11â-HSD2), which confers aldosterone specificity for mineralocorticoid receptors in distal tubules and collecting ducts, has been reported to be decreased or normal in patients with renal diseases. Our objective was to determine the role of aldosterone and 11â-HSD2 renal microsome activity, normalized for glomerular filtration rate (GFR), in maintaining K+ homeostasis in 5/6 nephrectomized rats. Male Wistar rats weighing 180-220 g at the beginning of the study were used. Rats with experimental CRF obtained by 5/6 nephrectomy (N = 9) and sham rats (N = 10) were maintained for 4 months. Systolic blood pressure and plasma creatinine (Pcr) concentration were measured at the end of the experiment. Sodium and potassium excretion and GFR were evaluated before and after spironolactone administration (10 mg·kg-1·day-1 for 7 days) and 11â-HSD2 activity on renal microsomes was determined. Systolic blood pressure (means ± SEM; Sham = 105 ± 8 and CRF = 149 ± 10 mmHg) and Pcr (Sham = 0.42 ± 0.03 and CRF = 2.53 ± 0.26 mg/dL) were higher (P < 0.05) while GFR (Sham = 1.46 ± 0.26 and CRF = 0.61 ± 0.06 mL/min) was lower (P < 0.05) in CRF, and plasma aldosterone (Pald) was the same in the two groups. Urinary sodium and potassium excretion was similar in the two groups under basal conditions but, after spironolactone treatment, only potassium excretion was decreased in CRF rats (sham = 0.95 ± 0.090 (before) vs 0.89 ± 0.09 µEq/min (after) and CRF = 1.05 ± 0.05 (before) vs 0.37 ± 0.07 µEq/min (after); P < 0.05). 11â-HSD2 activity on renal microsomes was lower in CRF rats (sham = 0.807 ± 0.09 and CRF = 0.217 ± 0.07 nmol·min-1·mg protein-1; P < 0.05), although when normalized for mL GFR it was similar in both groups. We conclude that K+ homeostasis is ...


Assuntos
Animais , Masculino , Ratos , /fisiologia , Homeostase/fisiologia , Falência Renal Crônica/metabolismo , Microssomos/enzimologia , Potássio/metabolismo , /metabolismo , Aldosterona/sangue , Pressão Sanguínea/fisiologia , Falência Renal Crônica/enzimologia , Nefrectomia , Ratos Wistar
11.
Miner Electrolyte Metab ; 13(1): 26-32, 1987.
Artigo em Inglês | MEDLINE | ID: mdl-3587181

RESUMO

The role of corticosteroid hormones in proximal tubular acidification was studied in control, sham-operated and adrenalectomized (ADX) rats by means of the stopped-flow microperfusion technique and by measurement of tubular acidification kinetics with pH microelectrodes. Rats were adrenalectomized 48 h before experiments, and aldosterone, corticosterone and 18-OH corticosterone (18-OH-B) were given intramuscularly 100 and 40 min before starting the experiments. Stationary proximal luminal pH increased from 6.78 to 7.03 after ADX, while acidification half-times (t1/2) increased from 4.41 to 11.43 s. In consequence, net bicarbonate reabsorption fell from 2.18 to 0.50 nmol/cm2 X s after ADX. The administration of the three hormones stimulated tubular acidification, bicarbonate reabsorption reaching 1.18-1.28 nmol/cm2 X s. These data suggest that proximal tubular acidification is stimulated by both mineralo- and glucocorticoid hormones and by 18-OH-B; their mechanisms of action is discussed on the basis of a recently described model.


Assuntos
11-Hidroxicorticosteroides/farmacologia , Túbulos Renais Proximais/metabolismo , Equilíbrio Ácido-Base/efeitos dos fármacos , Adrenalectomia , Animais , Bicarbonatos/metabolismo , Concentração de Íons de Hidrogênio , Túbulos Renais Proximais/efeitos dos fármacos , Perfusão , Ratos , Ratos Endogâmicos
12.
Can J Physiol Pharmacol ; 67(6): 607-14, 1989 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-2505914

RESUMO

The role of adrenocortical steroids in distal nephron acidification was studied in rats by measuring urine minus blood PCO2 differences (U-B PCO2) in control, sham-operated, and adrenalectomized (ADX) animals. Operations were performed 48 h before experiments. During the experiments, all rats received an infusion of 0.35-0.60 M NaHCO3, leading to urine bicarbonate concentrations in the order of 100-200 mM. Adrenalectomized rats had significantly decreased U-B PCO2 (11.9 +/- 1.99 mmHg; 1 mmHg = 133.3 Pa) with respect to sham-operated rats (39.9 +/- 1.26 mmHg). In another series, ADX rats received supplements of the adrenal steroids corticosterone, aldosterone, and 18-hydroxycorticosterone 100 min before the experiment. U-B PCO2 increased after hormone administration: corticosterone, 30.0 +/- 2.13 mmHg; aldosterone, 26.6 +/- 1.74 mmHg; 18-hydroxycorticosterone, 29.0 +/- 1.60 mmHg; but none restored these values to normal. Combinations of two hormones were also used; only aldosterone + corticosterone restored U-B PCO2 to normal: 39.0 +/- 1.66 mmHg. Renal phosphate excretion (but not urine phosphate levels) decreased significantly in ADX as compared with sham-operated rats. Extracellular volume was not significantly affected in ADX rats, which received ad libitum 0.9% NaCl for drinking. It is concluded that distal tubular acidification, as evaluated by U-B PCO2, is dependent on cortical steroids.


Assuntos
Corticosteroides/farmacologia , Adrenalectomia , 18-Hidroxicorticosterona/farmacologia , Aldosterona/farmacologia , Animais , Bicarbonatos/urina , Dióxido de Carbono/metabolismo , Corticosterona/farmacologia , Espaço Extracelular/metabolismo , Taxa de Filtração Glomerular/efeitos dos fármacos , Concentração de Íons de Hidrogênio , Masculino , Ratos , Ratos Endogâmicos
13.
Acta Physiol Pharmacol Latinoam ; 35(4): 415-7, 1985.
Artigo em Inglês | MEDLINE | ID: mdl-2940802

RESUMO

Using high pressure liquid chromatography (HPLC) and/or gas liquid chromatography (GLC), corticosterone plasma levels were determined in rats at various periods after adrenalectomy. Lowest levels could be found 24 to 48 hours after the operation.


Assuntos
Adrenalectomia , Corticosterona/sangue , Animais , Cromatografia Gasosa , Cromatografia Líquida de Alta Pressão , Corticosterona/metabolismo , Masculino , Período Pós-Operatório , Ratos , Ratos Endogâmicos
14.
Artigo em Inglês | MEDLINE | ID: mdl-9201315

RESUMO

Urinary parameters related to acid base homeostasis were studied in adrenalectomized rats (ADX) as well as in ADX treated with physiological doses of corticosterone (B), aldosterone (aldo) or 18-Hydroxycorticosterone (18HOB) during 1, 3 or 5 days, under basal conditions and after gravage with 200 mM HCI. The results showed: a) persistent effect of B and 18HOB increasing titratable acidity principally in response to acidosis; b) an increased phosphate elimination in acidotic B treated ADX on the first day, and in 18 HOB treated ADX on days 3 and 5; c) pronounced increases in blood pH and blood bicarbonate levels provoked by the three steroids on day 1; d) increments of ammonium elimination in response to acidosis by aldo treatments on the first day, while B and 18HOB increase ammonium elimination under almost all conditions during the whole experiment; e) the effects of B and 18 HOB would be independent of an increase in sodium retention as well as glomerular filtration rate.


Assuntos
Equilíbrio Ácido-Base/efeitos dos fármacos , Aldosterona/farmacologia , Corticosterona/farmacologia , Animais , Rim/efeitos dos fármacos , Rim/fisiologia , Masculino , Ratos , Ratos Sprague-Dawley
15.
Can J Physiol Pharmacol ; 75(10-11): 1226-31, 1997.
Artigo em Inglês | MEDLINE | ID: mdl-9431447

RESUMO

We studied the effect of adrenalectomy and acute hormone replacement, using physiological doses of natural corticosteroids, on the kinetics of the Na+/H+ exchanger in brush border membrane vesicles. We collected the data using the acridine orange uptake technique. Adrenalectomized (ADX) rats presented a decreased maximal rate (Vmax) when compared with sham-operated animals (30,000 versus 41,000 fluorescent units/min, respectively). Administration of corticosterone (B) to ADX rats restored Vmax to values above control (up to 66,000 fluorescent units/min). Smaller doses of 18-OH-B led to similar results. K(m) (16 mM) remained the same for all the groups. Amiloride behaved as a pure competitive inhibitor, with a Ki = 0.02 mM and an I50 = 98 microM (in the presence of 50 mM sodium gluconate). The presence of sodium in the external buffer, before adding the vesicles, inhibited the exchange, with an I50 = 2 mM. We observed, a significant decrease in the Na+/H+ exchanger under non-acidotic conditions in response to adrenalectomy. Acute administration of physiological doses of natural occurring corticosteroids reversed the effect.


Assuntos
18-Hidroxicorticosterona/farmacologia , Anti-Inflamatórios/farmacologia , Corticosterona/farmacologia , Rim/enzimologia , Microvilosidades/enzimologia , Trocadores de Sódio-Hidrogênio/metabolismo , Equilíbrio Ácido-Base/efeitos dos fármacos , Adrenalectomia , Amilorida/farmacologia , Animais , Diuréticos/farmacologia , Rim/efeitos dos fármacos , Rim/ultraestrutura , Cinética , Masculino , Microvilosidades/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Sódio/farmacologia
16.
Acta Physiol Lat Am ; 29(6): 305-14, 1979.
Artigo em Inglês | MEDLINE | ID: mdl-263223

RESUMO

In acute experiments, aldosterone (aldo), 18-hydroxycorticosterone (18 OH B) or corticosterone (B) were administered to adrenalectomized rats and parameters related to acid-base balance measured in urine samples collected for 3.5 hours after injection. Aldo reduced sodium excretion but did not affect pH nor the outputs of K, NH4+, CO3H-, phosphates nor titratable acidity. 18 OH B increased the excretion of titratable acidity and reduced drastically that of CO3H-. The lowest effective dose (3 micrograms) promoted Na excretion while the highest dose employed (6 micrograms) reduced pH and Na excretion. B increased the excretions of phosphates and ammonium, the former drastically. Potassium output either increased or did not change, and pH augmented marginally. It is postulated that a) 18 OH B is a naturally occurring steroid eliciting urine-acidification not necessarily accompanied by sodium retention; and b) at least B and 18 OH B in the rat, possess hormonal roles according to which the latter promotes the presence of protons, and the former, that of acute proton-acceptors in the lumen of tubuli.


Assuntos
18-Hidroxicorticosterona/farmacologia , Equilíbrio Ácido-Base/efeitos dos fármacos , Córtex Suprarrenal/fisiologia , Aldosterona/farmacologia , Corticosterona/análogos & derivados , Corticosterona/farmacologia , Animais , Bicarbonatos/urina , Rim/fisiologia , Masculino , Fosfatos/urina , Potássio/urina , Compostos de Amônio Quaternário/urina , Ratos , Ratos Endogâmicos , Sódio/urina
17.
Can J Physiol Pharmacol ; 70(5): 695-700, 1992 May.
Artigo em Inglês | MEDLINE | ID: mdl-1423011

RESUMO

The role of amiloride-dependent sodium channels in the action of adrenal cortical steroids on urine-blood PCO2 (U-B PCO2) differences was studied in bicarbonate-infused and amiloride-treated adrenalectomized rats. U-B PCO2 was significantly reduced by amiloride in bicarbonate-infused control rats. Adrenalectomy further reduced U-B PCO2 in amiloride-treated, bicarbonate-infused rats (from 27.9 +/- 1.82 mmHg in sham-operated rats to 21.3 +/- 1.58 mmHg in adrenalectomized (ADX) rats) (1 mmHg = 133.322 Pa). Acute administration of corticosterone and 18-hydroxycorticosterone (18-OH-B), but not of aldosterone, caused recovery of U-B PCO2 to the level of sham-operated animals treated with amiloride. Aldosterone did not affect U-B PCO2 in the presence of amiloride (21.9 mmHg ADX group vs. 20.98 mmHg aldosterone group). Results are compatible with aldosterone affecting distal H ion secretion mostly by a sodium and potential difference dependent mechanism, while corticosterone and 18-OH-B should act by other mechanisms (e.g., increased luminal buffer level).


Assuntos
Corticosteroides/fisiologia , Amilorida/farmacologia , 18-Hidroxicorticosterona/farmacologia , Adrenalectomia , Aldosterona/farmacologia , Animais , Dióxido de Carbono , Corticosterona/farmacologia , Taxa de Filtração Glomerular , Concentração de Íons de Hidrogênio , Masculino , Néfrons/efeitos dos fármacos , Néfrons/metabolismo , Ratos , Ratos Endogâmicos
18.
Endocr Res ; 24(3-4): 601-5, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9888545

RESUMO

Up to now, only glucocorticoids were thought to act on the renal proximal Na+/H+ exchanger. Using fluorimetric techniques we studied the kinetics of Na+/H+ exchange in brush border vesicles from ADX rats treated with increasing doses of corticosterone (B) and 18-hydroxycorticosterone (18OHB). Significant linear correlations were obtained when the Vmax of each treatment were plotted against log doses. 18OHB exhibits a slightly higher sensitivity than B and log-dose responses were steeper for 18OHB than for B treated rats. Differences between both treatments were highly significant at the 4.8 microg/100 g level, corresponding to the physiological blood level of 18OHB. Physiological doses of both steroids elicited equal Na+/H+ exchange-responses. 18OHB is not a glucocorticoid since even 88 microg/100 g did not promote hepatic glycogen deposition while the same dose of B increases glycogen deposits 3.5-fold. These results demonstrate the importance of the Na+/H+ exchanger as a mediator between corticoid action and H+ transport and that of the non-glucocorticoid 18OHB in this process.


Assuntos
18-Hidroxicorticosterona/farmacologia , Corticosterona/farmacologia , Túbulos Renais Proximais/metabolismo , Adrenalectomia , Animais , Proteínas de Transporte/metabolismo , Relação Dose-Resposta a Droga , Glicogênio/metabolismo , Túbulos Renais Proximais/efeitos dos fármacos , Fígado/metabolismo , Masculino , Microvilosidades/metabolismo , Ratos , Ratos Sprague-Dawley , Simportadores de Cloreto de Sódio-Potássio
19.
Am J Physiol Regul Integr Comp Physiol ; 280(6): R1627-31, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11353664

RESUMO

The normal aging process is accompanied by a progressive deterioration of renal function. We studied the kinetics of proximal tubular acidification of young (3 mo) and aging (22 mo) rats using in vivo and in vitro techniques. Blood acid-base parameters were similar in both groups. The maximum velocity of the Na(+)/H(+) exchange (NHE) in brush-border membrane vesicles (BBMV) showed a 72% decrease in aging compared with young rats, whereas the Michaelis constant remained unchanged. The NHE3 isoform of the Na(+)/H(+) exchanger was detected in BBMV by Western blot in both groups, and a decrease of 90% in the abundance was observed in aging rats. Micropuncture experiments with simultaneous luminal and peritubular perfusion with phosphate Ringer and continuous measurement of intratubular pH showed an acidification rate constant 34% smaller in aging compared with young rats. Proton flux was 48% lower in aging than in young rats. The present results suggest that proximal tubular acidification is impaired with aging.


Assuntos
Ácidos/metabolismo , Envelhecimento/metabolismo , Túbulos Renais Proximais/metabolismo , Animais , Bicarbonatos/sangue , Western Blotting , Concentração de Íons de Hidrogênio , Técnicas In Vitro , Cinética , Masculino , Microvilosidades/metabolismo , Concentração Osmolar , Punções , Ratos , Ratos Wistar , Trocadores de Sódio-Hidrogênio/metabolismo , Fatores de Tempo
20.
Artigo em Inglês | MEDLINE | ID: mdl-1294270

RESUMO

The specific uptake of tritiated 18-hydroxycorticosterone (18-OH-B) by purified cell nuclear fractions and cytosol of medulla oblongata, pons, amygdala, anterior pituitary, hypothalamus, hippocampus, preoptic-area and lung from adrenalectomized animals was investigated after incubation of tissue sections with radioactive ligand. We found that 18-OH-B was taken up mainly by nuclei obtained from pons and medulla oblongata; this profile differs from previous observations with the closely related steroids corticosterone and aldosterone, which are mostly concentrated by the limbic system. Based on this finding, as well as on former studies with 18-OH-B, we suggest that this steroid may exert its action on renal excretion of protons as well as on central nervous system structures involved in respiratory regulation, related to that excretion.


Assuntos
18-Hidroxicorticosterona/farmacocinética , Sistema Nervoso Central/metabolismo , Frações Subcelulares/metabolismo , Adrenalectomia , Animais , Sítios de Ligação , Sistema Nervoso Central/citologia , Técnicas In Vitro , Masculino , Ratos , Ratos Sprague-Dawley
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