Protective effects of exogenous and endogenous hydrogen sulfide in mast cell-mediated pruritus and cutaneous acute inflammation in mice.

The recently described 'gasomediator' hydrogen sulfide (H2S) has been involved in pain mechanisms, but its effect on pruritus, a sensory modality that similarly to pain acts as a protective mechanism, is poorly known and controversial. The effects of the slow-releasing (GYY4137) and spontaneous H2S donors (Na2S and Lawesson's reagent, LR) were evaluated in histamine and compound 48/80 (C48/80)-dependent dorsal skin pruritus and inflammation in male BALB/c mice. Animals were intradermally (i.d.) injected with C48/80 (3µg/site) or histamine (1µmol/site) alone or co-injected with Na2S, LR or GYY4137 (within the 0.3-100nmol range). The involvement of endogenous H2S and KATP channel-dependent mechanism were also evaluated. Pruritus was assessed by the number of scratching bouts, whilst skin inflammation was evaluated by the extravascular accumulation of intravenously injected 125I-albumin (plasma extravasation) and myeloperoxidase (MPO) activity (neutrophil recruitment). Histamine or C48/80 significantly evoked itching behavior paralleled by plasma extravasation and increased MPO activity. Na2S and LR significantly ameliorated histamine or C48/80-induced pruritus and inflammation, although these effects were less pronounced or absent with GYY4137. Inhibition of endogenous H2S synthesis increased both Tyrode and C48/80-induced responses in the skin, whereas the blockade of KATP channels by glibenclamide did not. H2S-releasing donors significantly attenuate C48/80-induced mast cell degranulation either in vivo or in vitro. We provide first evidences that H2S donors confer protective effect against histamine-mediated acute pruritus and cutaneous inflammation. These effects can be mediated, at least in part, by stabilizing mast cells, known to contain multiple mediators and to be primary initiators of allergic processes, thus making of H2S donors a potential alternative/complementary therapy for treating inflammatory allergic skin diseases and related pruritus.

Qualitative and quantitative reversed-phase high performance liquid chromatographic analysis of glycoprotein hormones in the presence of a large excess of human serum albumin.

The present work describes reversed-phase high performance liquid chromatographic methodologies (RP-HPLC) for the qualitative and quantitative analysis of the human glycoprotein hormones thyrotropin (hTSH), follitropin (hFSH), choriogonadotropin (hCG) and lutropin (hLH) in the presence of a large excess (up to 250:1) of human serum albumin (HSA). Chromatographic profiles with a good separation between the hormone and HSA were obtained by using a C4 column and specific gradient elution conditions for each hormone. Parameters such as resolution factor, tailing factor and relative retention time, were determined, and are useful for the evaluation of the quality of the separation obtained between the active pharmaceutical ingredient and the excipient present in the final formulation. The potential of each method for quantification of both HSA and the hormone was also demonstrated. Besides furnishing chromatographic quantifications that can substitute for in vivo bioassays and animal use, the chromatograms also provide a direct panorama of the quality and heterogeneity of the protein of interest.

A pilot study on potency determination of human follicle-stimulating hormone: a comparison between reversed-phase high-performance liquid chromatography method and the in vivo bioassay.

Reversed-phase high-performance liquid chromatography (RP-HPLC) was compared with the classical Steelman-Pohley bioassay (BA), based on animal use, for the determination of human follicle-stimulating hormone (hFSH) biological activity. A linear relationship (BA(IU)=0.9925 RP-HPLC(IU)-1.3165) with a highly significant correlation (r=0.9371; p<0.0001; n=24) was found for these two methods for six hFSH preparations of different origins. The mean difference between the bioactivity predicted from RP-HPLC data via this equation and the mean of the bioactivities obtained with the two methods for six other hFSH preparations was -1.4%, with a 95% confidence interval of -9.3 to +6.6%. The precision of these parameters was 1.63% and 2.82%, respectively. These results demonstrate that RP-HPLC is a viable physical-chemical alternative to the use of an in vivo bioassay for hFSH potency determination, applicable also to hFSH Standards containing large amounts of human serum albumin.

Analysis of human luteinizing hormone and human chorionic gonadotropin preparations of different origins by reversed-phase high-performance liquid chromatography.

Specific reversed-phase high-performance liquid chromatography conditions are reported for the analysis of recombinant and native human luteinizing hormone (hLH) and human chorionic gonadotropin (hCG) preparations. Heterodimeric hLH, hCG and their alpha- and beta-subunits migrated with significantly different retention times (t(R)) in the following order of increasing hydrophobicity: alpha-hCG

Efficient isolation of the subunits of recombinant and pituitary glycoprotein hormones.

Complete dissociation into subunits was attained by incubating Chinese hamster ovary (CHO)-derived or native human thyrotropin, follitropin and lutropin overnight at 37 degrees C in acetic acid. The alpha-and beta-subunits of the pituitary glycoprotein hormones were rapidly and quantitatively isolated by reversed-phase high-performance liquid chromatography (RP-HPLC). A dissociation efficiency of > 98% was obtained on the basis of mass determinations of the heterodimers and subunits carried out via mass spectrometry. CHO-derived or native subunits were isolated on a C4 column (80-90% total recovery) and characterized comparatively for purity, hydrophobicity, molecular mass and charge distribution by HPLC, mass spectrometry, sodium dodecylsulfate-polyacrylamide gel electrophoresis and isoelectric focusing. Thyrotropin was used as a model for showing that, after subunit reassociation, the in vivo bioactivity of the hormone was completely restored. The method described is mild, practical, flexible, and can be adapted to dissociate microgram amounts of native or recombinant glycoprotein hormones, allowing characterization of each subunit.

Efeito do líquido folicular bovino tratado com carväo ativado na secreçäo de FSH em novilhas pré-púberes intatas e ovariectomizadas / Effect of charcoal-treated bovine follicular fluid on the secretion of FSH in ovariectomized and intact prepubertal heifers

O presente trabalho objetivou determinar o efeito do líquido folicular bovino tratado com carväo ativado (LFb) na secreçäo do hormônio folículo estimulante (FSH) de novilhas pré-púberes ovariectomizadas ou intatas. A aplicaçäo de LFb (quatro injeçöes de 10 ml com intervalo de 8 horas) provocou uma queda de aproximadamente 44 por cento na concentraçäo plasmática de FSH nas novilhas ovariectomizadas, mas näo teve efeito nas novilhas intatas. Näo foi observada hipersecreçäo de FSH após o término da aplicaçäo do LFb. Esses resultados sugerem que proteínas presentes no LFb atuam ao nível hipofisiário para inibir a secreçäo de FSH e, diferentemente das intatas, as novilhas ovariectomizadas constituem um modelo adequado para evidenciar esse efeito, particularmente quando o LFb possui reduzida atividade supressora do FSH

Perfis endócrinos e taxa de ovulaçäo de vacas superovuladas com FSH após imunizaçäo passiva contra líquido folicular bovino livre de esteróides / Endocrine profiles and ovulation rate of cow superovulated with FSH following passive immunization against steroid free-bovine follicular fluid

Dez vacas multíparas, secas, foram distribuídas aleatoriamente em dois grupos de cinco animais cada. Nos dias 8 a 12 do diestro, o primeiro grupo recebeu 100 ml de anti-soro contra líquido folicular livre de esteróides (anti-LFb) produzido em ovelhas ovariectomizadas. O segundo grupo (controle) recebeu 100 ml de soro de ovelhas näo-imunizadas. Seis horas após a aplicaçäo, os dois grupos foram superovulados com FSH (18 NIH-FSH-S1 unidades) e LH (0,29 NIH-LH-S1 unidades) administrados em quantidades decrescentes durante quatro dias. Na manhä do terceiro dia, foi administrada uma dose luteolítica de cloprostenol. Duas inseminaçöes foram realizadas 48 e 60 horas após. Os embriöes foram recuperados pelo método cervical 7 dias após a primeira inseminaçäo. Amostras de sangue foram coletadas durante todo o período experimental para determinar, por radioimunoensaio, as concentraçöes plasmáticas de FSH, LH e progesterona. Todas as vacas do grupo imunizado e 3 do grupo controle apresentaram mais de 2 CL. Näo existiu diferença significativa (p>0,05) na taxa de ovulaçäo entre os grupos imunizado e controle (14,4 e 9,9, respectivamente). O número de embriöes recuperado näo foi significativamente diferente (p>0,05) entre os grupos, embora o grupo imunizado tenha apresentado maior número de embriöes transferíveis (3,4 ñ 1,0 versus 0,8 ñ 0,4, p<0,05). As concentraçöes de gonadotrofinas plasmáticas näo foram correlacionadas com a taxa de ovulaçäo ou com o número de embriöes recuperados. As concentraçöes de progesterona plasmática foram positivamente correlacionadas (r = 0,88, p<0,01) com a taxa de ovulaçäo. Os resultados sugerem que o anti-LFb, aplicado antes da superovulaçäo, näo reduz a variabilidade da resposta ovariana