CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / A ExtraÃÃo do terceiro molar à um procedimento comum, freqÃentemente associado com dor de intensidade de moderada ou grave, e que afeta um nÃmero significante de pacientes, o que torna os estudos clÃnicos que avaliam a dor associada com a exodontia dos terceiros molares relativamente fÃceis de se executar. O objetivo deste estudo foi determinar a eficÃcia e a seguranÃa da combinaÃÃo terapÃutica de piroxicam, dexametasona, citrato de orfenadrina e cianocobalamina (RheumazinÂ) em comparaÃÃo ao piroxicam isoladamente (FeldeneÂ) em um modelo de cirurgia do terceiro molar inferior. Neste estudo, que foi do tipo randomizado e duplo cego, foram incluÃdos oitenta pacientes selecionados para a exodontia do terceiro molar inferior. Os pacientes receberam Rheumazin ou Feldene 30 min depois da extraÃÃo do terceiro molar inferior e, a partir daÃ, uma vez ao dia durante 4 dias sucessivos. A intensidade da dor foi determinada por meio de uma escala visual analÃgica e pela quantidade de medicaÃÃo de escape utilizada pelos pacientes (paracetamol). O edema facial foi avaliado atravÃs de medidas da face usando uma escala mÃtrica calibrada (mm). Ainda, foram tambÃm avaliados os efeitos adversos e o grau de satisfaÃÃo em relaÃÃo aos tratamentos, ambos relatados pelos pacientes. Embora os resultados tenham mostrado que nÃo houve diferenÃa estatÃstica no edema facial entre os dois grupos, Rheumazin reduziu a dor na 6a e 120a h de tratamento. Rheumazin tambÃm demonstrou um melhor perfil de seguranÃa, prevenindo efeitos adversos tais como nÃusea, indisposiÃÃo e dor epigÃstrica, dentre outros, quando comparado ao FeldeneÂ. Este achado torna o Rheumazin uma boa opÃÃo para o tratamento no pÃs-operatÃrio da remoÃÃo do terceiro molar inferior. / Third molar extraction is a common procedure with pain frequently moderate or severe in intensity, and with sufficient numbers of patients to make studies relatively easy to perform. The aim of this study was to determine the efficacy and the safety of the therapeutic combination of piroxicam, dexamethasone, orphenadrine citrate and cyanocobalamin (RheumazinÂ) in comparison to piroxicam alone (FeldeneÂ) in a mandibular third molar surgery model. Eighty patients selected for removal of the third molar were included in this study which was randomized and double blind. They received Rheumazin or Feldene po 30 min after tooth extraction and once daily for 4 consecutive days. Pain was determined by a visual analogue scale and by the need for escape analgesia (paracetamol). Facial swelling was evaluated using a tape measuring method. Record of adverse effects and patientâs satisfaction was also considered. Although the results showed that there was no statistically significant difference in facial swelling between the two groups, Rheumazin reduced pain at 6th and 120th h of treatment. Rheumazin also demonstrated a better safety profile preventing adverse effects including nausea, indisposition and epigastric pain, among others, when compared to FeldeneÂ. This fact makes Rheumazin a good choice for post-surgery treatment in third molar removal

Aprofundamos o estudo dos efeitos farmacológicos da dexametasona, indometacina e tenoxicam e de uma droga citostática (metotrexato), assim como a análise dos mecanismos envolvidos na estimulação flogógena causada por agentes de intensidades fraca, média e forte. Para isso. empregamos o teste edemogênico, que demonstrou ser os fármacos antiinflamatórios não esteróides (tenoxicam e indometacina), os de maior potência na inibição da exsudação plasmática induzida pela paracoccidioidina. Todavia, com agentes flogógenos de intensidade média (carragenina), o metotrexato foi o medicamento mais potente; enquanto que com a placa microbiana dental (agente forte), a dexametasona e a indometacina foram os de maior potência antiinflamatória. Por meio da análise histomorfométrica relativa dos granulomas induzidos por esse último agente, verificamos, até 14 dias, a maior potência antiinflamatória apresentada pelo tenoxicam, comparativamente à da indometacina - em relação à inibição da região central de necrose supurativa-, demonstrando efeito semelhante ao da dexametasona; não obstante, nesse período experimental, em relação à inibição da densidade do volume do tecido granulomatoso, os fármacos mais potentes terem sido a indometacina e a dexametasona. Após 14 dias, foi constatada diferença não significativa (p>0.05) entre o efeito apresentado pelo tenoxicam e o da indometacina. O acentuado efeito apresentado pelos NSAIDs em relação à inibição da densidade de volume dos macrófagos, semelhante ao do metotrexato, sugeriu que os NSAIDs inibiram a proliferação das células progenitoras mielóides dos monócitos/macrófagos. Também agiram tanto aumentando (21 dias) como inibindo (28 dias) a densidade de volume ocupada pelas fibras colágenas; enquanto que a dexametasona apresentou efeito contrário. Tais resultados indicaram que no processo inflamatório induzido por agentes flogógenos de intensidade forte (PMD), estimulores da acentuada produção de LTs e PGs, o emprego de antiinflamatórios esteróides e não esteróides foi vantajosa em relação ao fármaco citostátco. / Was studied comparatively the mechanisms of action and the antiinflammatory effect presented by dexamethasone, tenoxican, indomethacin and methotrexate in acute and chronic inflammation induced by agent flogogenous of minim, media and elevated intensity. With the employ of edemogenic test was verified that the effect presented by nonsteroid antiinflammatory (tenoxican and indomethacin), in relation to inhibition of the plasmatic exsudation induced by paracoccidioidin, was more potent than other medicaments tested. Meanwhile, in the inhibition of the acute inflammation caused by carrageenan and dental microbian plaque, methotrexate, dexamethasone and indomethacin were the most potent pharmacs, respectively. The injection of the dental microbian plaque in the air pouch model induced two experimental granulomas susceptive to the antiinflammatory effects presented for the pharmacs tested, which were utilized in the determination of the weights and of the volume density occupied by structures presents in the periods experimental of 7, 14, 21 and 28 days. With relation the inhibition of the differential mid and dry weights, methotrexate and dexamethasone followed by indomethacin and tenoxican were the most effective pharmacs in decrescent order of potency. The histomorphometric studies of the volume density of the granulomatous tissue revealed that indomethacin reduced this structure comparatively to the tenoxican at 14 days. After this experimental period tenoxican presented the most potent anti-inflammatory effect; however, without significant statistical difference to indomethacin. Tenoxican too presented elevated inhibitory effect of the volume density of the region of supurative necrose (similar to dexamethasone) particularly along to first week. NSAIDs also showed in relation the inhibition of volume density of the collagen effect stimulator (21 days) and inhibitor (28 days), while that dexamethasone revealed contrary effect. The accentuate inhibitory effect of the volume density of macrophages presented by NSAIDs was similar to methotrexate, indicating that these medicaments possibly presented anti-mitotic effect to the progenitors myeloid cells of monocytes/macrophages. These results indicated that in the inflammatory process induced by flogogenous of strong intensity, stimulators of increased production of LTS and PGs, the administration of steroids and non-steroids anti-inflammatory was advantageous in relation to methotrexate.

A administração tópica de colírios é a maneira mais conveniente de se tratar doenças oculares. O grande desafio para a tecnologia farmacêutica é garantir que o fármaco administrado nessa forma farmacêutica chegue ao local de ação em concentrações adequadas, com efeitos adversos reduzidos, tempo de ação prolongado e dose única. Para tanto, o desenvolvimento de sistemas de liberação e de estratégias adequadas de administração tornam-se necessários. Assim, o objetivo deste trabalho foi avaliar a influência da iontoforese na penetração ocular de dendrímeros de poliamidoamina (PAMAM) de geração 4, com diferentes grupos superficiais (PAMAM G4, catiônico e PAMAM G3.5, aniônico), preparar complexos desses dendrímeros com um anti-inflamatório modelo, a dexametasona (Dexa), e avaliar a influência da associação de dendrímeros e iontoforese na penetração corneal da Dexa em modelos ex vivo e in vivo. Complexos Dexa-PAMAM foram obtidos e caracterizados por espectroscopia de infravermelho e ressonância magnética nuclear (H1-RMN, 13C-RMN e DOSY), espalhamento dinâmico de luz e espectroscopia UV/vis para avaliar a formação dos complexos, seu tamanho e potencial zeta, além de alterações na solubilidade da Dexa. A velocidade de liberação da Dexa dos complexos foi verificada por estudos de liberação in vitro utilizando membrana sintética. A penetração e distribuição dos PAMAMs na córnea e sua influência na penetração da Dexa foi avaliada ex vivo utilizando córnea de porco, microscopia confocal de varredura a laser (MCVL) e cromatografia de ultra performance aliada a um detector de massas para quantificação do fármaco permeado. A citotoxicidade dos PAMAMs foi avaliada em cultura de células epiteliais da retina e células epiteliais da córnea. Por fim, verificou-se in vivo a influência da iontoforese e dos PAMAMs sobre a quantidade de Dexa no humor aquoso de olhos de coelhos. Os estudos de caracterização indicaram que a Dexa foi incorporada aos PAMAMs e que esses complexos apresentaram cerca de 50 nm de tamanho médio pela técnica de NTA, com a presença de partículas pequenas e agregadas quando dispersos em meio fisiológico e potencial zeta de + 6,4 mV e -18,5 mV para Dexa-PAMAM G4 e Dexa-PAMAM G3.5, respectivamente. A solubilidade aparente da Dexa aumentou 3,9 e 10,3 vezes nos complexos com PAMAM G4 e PAMAM G3.5, respectivamente. O PAMAM G3.5 e PAMAM G4 diminuiram 82 e 1,7 vezes, respectivamente, o coeficiente de difusão da Dexa. Os estudos ex vivo indicaram que a iontoforese foi capaz de direcionar os dendrímeros para dentro da córnea, além de aumentar 2,9, 5,6 e 3,0 vezes a quantidade de Dexa permeada a partir das formulações que continham Dexa livre, Dexa-PAMAM G4 e Dexa-PAMAM G3.5, respectivamente. Aumentou também a quantidade de Dexa retida na córnea em aproximadamente 2 vezes para todas as formulações. Os experimentos de citotoxicidade evidenciaram a maior toxicidade do PAMAM G4 e sua dependência da concentração e tempo de incubação. Por fim, os experimentos in vivo mostraram que a iontoforese aumentou a concentração de Dexa no humor aquoso cerca de 2, 2,5 e 6,6 para a Dexa livre, Dexa-PAMAM G4 e Dexa-PAMAM G3.5, respectivamente. Portanto, a associação de dendrímeros PAMAM com a iontoforese representa uma estratégia promissora para a administração tópica direcionada e sustentada de fármacos na córnea. / Topical administration of eye drops is the most convenient way for treatment of eye diseases. The challenge for the pharmaceutical technology is to ensure that the drug administered in the eye drops reaches the site of action in appropriate concentrations with reduced side effects, prolonged effect and single dose. Therefore, the development of drug delivery systems and appropriate strategies become necessary. The objective of this work was to evaluate the influence of iontophoresis in the ocular penetration of generation 4 polyamidoamine dendrimers (PAMAM) with different surface groups (PAMAM G4, cationic, and PAMAM G3.5, anionic), prepare complexes of these dendrimers with an anti-inflammatory drug model, dexamethasone (Dexa), and evaluate the influence of dendrimers and iontophoresis association on Dexa cornea penetration using ex vivo and in vivo models. Dexa-PAMAM complexes were obtained and characterized by infrared spectroscopy, nuclear magnetic resonance (H1-NMR, 13C-NMR and DOSY), dynamic light scattering and UV/VIS spectroscopy to evaluate the formation of the complexes, their size and zeta potential, as well as changes in drug solubility. Dexa release rate from complexes was determined from the in vitro release studies using synthetic membrane. The penetration and distribution of PAMAMs into the cornea and their influence in the ex vivo Dexa penetration was assessed using pig\'s cornea, confocal scanning laser microscopy (CSLM) and ultra performance chromatography coupled to a mass spectrometer for quantification of the drug permeated. PAMAMs cytotoxicity was assessed in culture of retina epithelial cells and cornea epithelial cells. Finally, the influence of iontophoresis and PAMAMs on Dexa concentration in the aqueous humor of rabbit eyes was evaluated in vivo. The characterization results showed that Dexa was incorporated to PAMAMs and that these complexes had an average size of approximately 50 nm using the NTA technique, with the distribution of small particles and aggregates when dispersed in physiological medium. The zeta potential of Dexa-PAMAM G4 and Dexa PAMAM G3.5 complexes were +6.4 mV and -18.5 mV, respectively. PAMAM G4 and G3.5 PAMAM enhanced Dexa solubility by 3.9 and 10.3-fold, respectively. PAMAM G3.5 and PAMAM G4 decreased by 82 and 1.7-fold Dexa diffusion coefficient. The ex vivo studies indicated that iontophoresis directed dendrimers into the cornea, increasing the amount of Dexa permeated by 2.9, 5.6 and 3.0-fold for the formulations containing free Dexa, Dexa-PAMAM G4 and Dexa-PAMAM G3.5, respectively. Iontophoresis also increased approximately 2-fold the amount of drug retained into the cornea for all formulations. The cytotoxicity experiments revealed that PAMAM G4 toxicity was dependent on the concentration and incubation time. Finally, the in vivo experiments showed that iontophoresis increased Dexa concentration in the aqueous humor by 2, 2.5 and 6.6-fold for free Dexa, Dexa-PAMAM G4 and Dexa-PAMAM-G3.5, respectively. Therefore, the combination of iontophoresis with PAMAM dendrimers represents a promising strategy for targeted and sustained topical drug delivery to the cornea.

INTRODUÇÃO: A introdução dos princípios da soft surgery desencadeou busca constante pela preservação auditiva, principalmente após a expansão dos critérios de inclusão para a cirurgia do implante coclear. Esses princípios cirúrgicos, associados a novos modelos de eletrodos e ao uso de fármacos no intraoperatório, têm sido utilizados a partir do melhor conhecimento da anatomia da orelha interna e da repercussão dos mecanismos inflamatórios desencadeados pelo trauma de inserção dos eletrodos. O objetivo deste estudo é avaliar o efeito de dexametasona tópica isolada e associada ao ácido hialurônico no intraoperatório de pacientes com audição residual submetidos ao implante coclear na preservação dos limiares tonais dos mesmos. MÉTODO: Foram avaliados 18 pacientes adultos com surdez severaprofunda submetidos à cirurgia de implante coclear divididos em 3 grupos: Implante coclear como grupo-controle, grupo 1; implante coclear com uso de dexametasona tópica no intraoperatório, grupo 2; e implante coclear com uso de dexametasona tópica associada ao ácido hialurônico no intraoperatório, grupo 3. Foram comparadas as médias dos limiares tonais nas frequências de 125, 250 e 500 Hz e nas frequências de 1000, 2000 e 4000 Hz no pré-operatório e no pós-operatório. RESULTADOS: A diferença entre as médias dos limiares tonais nas frequências baixas obtidas no 6º mês de pós-operatório e no pré-operatório foi de 28,03 dB + 6,77 dB no grupo 1, 30 dB + 14,53 dB no grupo 2 e 7,23 dB + 6,12 dB no grupo 3. Houve diferença estatisticamente significante dos valores do grupo 3 em relação ao grupo 1 e 2 (p = 0,002). A diferença entre as médias dos limiares tonais nas frequências altas obtidas no 6º mês de pós-operatório e no pré-operatório foi de 11,12 dB (DP + 9,71 dB) no grupo 1, 22,77 dB (DP + 12,79 dB) e 3,89 dB (DP + 3,1 dB). Houve diferença estatística entre os grupos 2 e 3 (p = 0,01). CONCLUSÕES: A associação do uso tópico de dexametasona e ácido hialurônico no intraoperatório de pacientes submetidos à cirurgia do implante coclear foi significantemente superior ao grupo controle e ao grupo no qual foi utilizado apenas a dexametasona tópica na preservação dos limiares auditivos. Por outro lado, o uso isolado de dexametasona tópica não demonstrou resultados superiores na preservação dos limiares acústicos quando comparado ao grupo controle / INTRODUCTION: The expansion of candidacy criteria for cochlear implantation led to a constant care for hearing preservation. The in-depth knowledge of the anatomy and function of the inner ear as well as the inflammatory repercussion caused by the insertion trauma led to the development of soft surgery principles, new electrode designs and pharmacotherapy. The purpose of this study was to compare the effects of topical dexamethasone isolated and associated with hyaluronic acid in hearing preservation in cochlear implantation. METHOD: Eighteen severely to profoundly hearing impaired adult patients were evaluated and divided into 3 groups: Cochlear implantation as a control group in group 1, cochlear implantation using topical dexamethasone intraoperatively in group 2 and cochlear implantation using topical dexamethasone associated with hyaluronic acid intraoperatively in group 3. Preimplant and postimplant low frequency and high frequency pure-tone average (PTA) from 125, 250, 500 Hz and 1000, 2000, 4000 Hz were calculated and compared from unaided audiograms. RESULTS: The mean changes in the low frequency PTA of preoperative and postoperative thresholds were 28.03 dB + 6.77 dB in group 1, 30 dB + 14.53 dB in group 2 and 7.23 dB + 6.12 dB in group 3. There was statistical difference comparing group 3 with group 1 and 2 (p = 0.002). The mean changes in the high frequency PTA of preoperative and postoperative thresholds were 11.12 dB + 9.71 dB in group 1, 22.77 dB + 12.79 dB e 3.89 dB + 3.1 dB. There was statistical difference between group 2 and 3 (p = 0.01). CONCLUSIONS: The use of topical dexamethasone associated with hyaluronic acid intraoperatively in cochlear implant surgery demonstrated a statistically significant difference in the preservation of low frequency thresholds when compared with the use of isolated topical dexamethasone and a control group. The use of isolated topical dexamethasone was not superior in hearing preservation when compared to a control group

Orientador: Francisco Benedito Teixeira Pessine / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-24T01:26:17Z (GMT). No. of bitstreams: 1 Marques_LeticiaPaifer_M.pdf: 4333961 bytes, checksum: dd287508ba192ad95556c2094f8d9d2a (MD5) Previous issue date: 2013 / Resumo: Através de modificações na estrutura química da molécula de pectina cítrica, polissacarídeo utilizado nas indústrias alimentícias como agente gelificante/espessante, foi desenvolvido um Sistema Depot para entrega subcutânea de nanopartículas lipídicas sólidas (NLS) e carreadores lipídicos nanoestruturados (CLN) contendo, respectivamente, Dexametasona (DXM) e Valerato de Betametasona (BTM). Os fármacos foram encapsulados nesses sistemas devido à necessidade de modificar seus perfis de liberação, diminuindo o número de aplicações e sua dosagem, reduzindo ocorrência de efeitos adversos. O produto da reação de oxidação da pectina cítrica foi caracterizado através de Espectroscopia da região do Infravermelho, Análise Termogravimétrica e Calorimetria Diferencial de Varredura. Os resultados indicaram o sucesso da reação, confirmado através da gelificação do hidrogel de pectina cítrica oxidada. As NLS e os CLN apresentaram valores de diâmetro médio em torno de 80nm, alta eficiência de encapsulação e perfis de liberação prolongada; para os CLN o fármaco BTM foi liberado ao longo de 144 horas e para as NLS o fármaco DXM foi liberado ao longo de 24 horas. Estes resultados mostram que as NLS de DXM poderiam ser utilizadas para tratar processos inflamatórios agudos e que os CLN de BTM seriam úteis no tratamento de processos inflamatórios crônicos / Abstract: A modified chemical structure of citrus pectin was used to develop a Depot system for subcutaneuous delivery of solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) containing, respectively, Dexamethasone (DXM) and Betamethasone Valerate (BTM). Citrus pectin is a polysaccharide used in food industry as a gelling/thickener agent. The drugs were encapsulated in this system with the aim to modify their release profiles. This would result in the reduction of the number of applications and dosage. As a consequence, it would also reduce adverse side effects that these drugs may cause. The citrus pectin oxidation product was characterized by Infrared Spectroscopy, Thermogravimetric Analysis and Differential Scanning Calorimetry. The results indicated that the reaction occurred. This was confirmed by gelation of the citrus pectin oxidation product. SLN and CLN showed values with diameters around 80nm, high encapsulation efficiency and sustained release profiles. BTM was released from the CLN over 144 hours and DXM was released from the NLS over 24 hours. These results showed that the DXM-NLS would be useful in the treatment of acute inflammatory processes. BTM-CLN could be applied in the treatment of chronic inflammatory processes / Mestrado / Físico-Química / Mestra em Química

Abstract The aim of the study was to evaluate the efficacy and safety of antenatal and postnatal corticosteroids in the prevention for mortality and acute and long-term morbidity in preterm infants. Altogether 109 eligible preterm infants participated in a randomized, multi-center, double-blinded controlled trial studying the efficacy of early dexamethasone (DX) treatment. The infants received either four doses of DX or placebo. DX treatment did not have a detectable influence on survival without bronchopulmonary dysplasia (BPD), severe intracranial hemorrhage, or periventricular leukomalacia. In a meta-analysis of 15 trials, we found that early prolonged DX treatment (> 96 h, n = 1594 infants) decreased the risk of BPD (RR 0.72 95% CI 0.61–0.87), whereas early short DX course did not (n = 1069 infants). However, prolonged DX increased the risk of gastrointestinal (GI) complications (RR 1.59 95% CI 1.02–2.46). Fifty-one very preterm infants participated in a randomized placebo-controlled trial studying early hydrocortisone (HC) started before 36 hours of age and continued for 10 days. The basal and stimulated serum cortisol levels were measured before the intervention. The study was interrupted because of GI perforations in the HC group. HC decreased the risk of patent ductus arteriosus. HC-treated infants with serum cortisol concentrations above the median had a high risk of GI perforation. HC increased survival without BPD among infants with low endogenous cortisol levels. Altogether 45 surviving infants were enrolled in the follow-up of the early HC trial at 2 years of age. None of the study patients had died after discharge. There was no difference in the recorded rehospitalization rate, growth characteristics, or neurological development between HC and placebo-treated children. Altogether 249 women pregnant at less than 34.0 gestational weeks participated in a randomized trial studying the efficacy of a single additional dose of betamethasone (BM). All of the 159 infants in the BM group and 167 in the placebo group were born before 36 weeks of gestation. Intact survival was comparable between the BM and placebo groups, whereas the need for surfactant therapy in RDS was increased in the BM group. According to a post hoc analysis of 206 infants delivered within 1–24 hours, the BM booster tended to increase the risk of RDS and to decrease intact survival.

Background: The incidence of postoperative nausea and vomiting (PONV) can be reduced by dexamethasone. Single dose administration may cause elevated blood glucose levels in obese adults. No data are available for children. Objective: The aim was to evaluate perioperative blood glucose changes related to body weight in children who received dexamethasone. Methods: This prospective observational study included 62 children. All patients received total intravenous anesthesia and a single dose of dexamethasone (0.15mg/kg, maximum 8mg). Blood glucose levels were measured up to 6 hours. Standard deviation scores (SDS) were calculated using age- and gender-specific BMI percentiles, p<0.05. Results: 62 children (11.5±2.9years, median SDS 0.43, 29% overweight/obese) were included. Blood glucose level increased from 5.52±0.52 to 6.74±0.84mmol/l 6h after dexamethasone without correlation to the BMI-SDS. Conclusions: This study shows an increase of perioperative blood glucose (normoglycemic ranges) after single dose of dexamethasone but no BMI-dependent effect in children. Therefore, low-dose dexamethasone may be used in obese children for PONV prophylaxis.

No description available.

Introduction: Waldenström's macroglobulinemia is a hematological neoplasm belonging to the group of monoclonal gammopathies, which includes systemic symptoms and those related to an increase in M paraprotein. Objective: To describe a case of cardiac amyloidosis associated with macroglobulinemia. Clinical case: Male patient who was admitted for asthenia, dysphonia, and who, during his evolution, developed progressive dyspnea, heart failure and pleural effusion. Additionally, echocardiography showed myocardial granular pattern, while pleural biopsy was positive for Congo red staining. Subsequently, he received treatment with bortezomib, dexamethasone and rituximab, with favorable evolution. Conclusions: In this disease, early diagnosis is an important advantage for survival. Therefore, its management is palliative of cardiac manifestations. The present case shows a diagnostic challenge, in which the less frequent etiologies of heart failure must be taken into account. / Revisión por pares

A substance that cross-reacts with antiserum to human atrial natriuretic peptide (ANP) is found in fish hearts. This ANP-like material increases sodium output from the gill and kidney while inhibiting sodium uptake in the gut. Mammalian ANP secretion is stimulated by glucocorticoids, and cortisol injection increases sodium output in salt-loaded fish. Therefore, we wanted to determine if the release of ANP in fish is sensitive to dexamethasone. Ventricle cardiocytes from the rainbow trout Oncorhynchus mykiss were treated with various doses of dexamethasone for 18 or 72 h. Single ventricle cells were then assayed for ANP release using a reverse hemolytic plaque assay and antiserum to human alpha-ANP. Incubation with 100 microM dexamethasone almost doubled the population of ventricle cells committed to ANP release (basal, 15.0 +/- 0.3% vs. Dexamethasone, 28.3 +/- 1.4%; values are percent plaque formation +/- SE). Stimulation of ANP secretion was dependent on dose and time of exposure to dexamethasone. These results suggest that ANP secretion in fish is regulated by glucocorticoids.