Efeito de duas variedades de feijão (Phaseolus vulgaris) no metabolismo lipídico de hamsters / Effect of two beans varieties (Phaseolus vulgaris) in hamster lipid metabolism

Introdução Os feijões comuns, da espécie Phaseolus vulgaris, são amplamente produzidos e consumidos no Brasil. As variedades, carioca e preto ganham destaque na região Sudeste do país. Encontra-se descrita na literatura a ação hipocolesterolemizante de algumas leguminosas, tais como, soja, tremoço e feijão caupi, que podem estar associados à redução do risco de doenças cardiovasculares. Objetivo Avaliar o potencial efeito da adição de farinhas de feijões carioca e preto (Phaseolus vulgaris) no metabolismo lipídico de hamsters alimentados com dieta contendo gordura saturada e colesterol. Métodos A produção das farinhas dos feijões envolveu as etapas de autoclavagem, congelamento, liofilização e moagem. As propriedades hipocolesterolemizantes destas farinhas foram avaliadas por meio de dois ensaios biológicos. Foram utilizados hamsters Golden Syrian, machos com 21 dias, pesando 60 ± 4g, que receberam as dietas experimentais ad libitum. No Ensaio A, os animais foram separados em 3 grupos, diferenciados pela dieta. Todas as dietas eram hipercolesterolemizantes [13.5 por cento de gordura de coco e 0.1 por cento colesterol] e tinham as mesmas quantidades de proteínas, carboidratos, fibras, vitaminas e minerais. O Grupo Controle (C) tinha como fonte protéica a caseína; no Grupo Feijão Carioca (FC) a farinha de feijão carioca representou 15 por cento do peso total da dieta e no Grupo Feijão Preto a farinha de feijão preto representou 15 por cento do peso total da dieta. No Ensaio B, os animais foram separados em três grupos novamente. Desta vez, a única diferença entre os grupos foi quanto a fonte protéica, para o grupo controle (C) somente caseína, para o grupo feijão carioca (FC), 67 por cento de feijão e 7,5 por cento de caseína e para o grupo feijão preto (FP), 62 por cento de feijão e 7,5 por cento de caseína. Nos dois ensaios, após 21 dias de experimento, foi realizada coleta de materiais biológicos (plasma, fígado e fezes). Resultados O processo de produção d...

Sex differences in the excretion of fecal glucocorticoid metabolites in the Syrian hamster.

We verified the relevance of measuring fecal glucocorticoid metabolites (FGM) to assess the stress response of the Syrian hamster. Male and female hamsters (n = 10 each) were submitted to an adrenocorticotropic hormone (ACTH) challenge test, whereas animals in the control group received 0.5 mL of sterile isotonic saline solution. All feces voided by each animal were collected at 4 h intervals from 24 h before (baseline) until 48 h after injections. FGM were quantified using an 11-oxoetiocholanolone enzyme immunoassay (EIA). Basal concentrations of FGM were almost four times higher in males than in females. Following ACTH administration, FGM levels started rising from 8 h onwards, reaching peak concentrations 20 or 28 h post injection in males and females, respectively. Despite the much higher absolute concentrations present in males, the relative increase (500%) in response to the ACTH stimulation was similar in both sexes. Sex differences in FGM levels are in accordance with results reported by others regarding the hamster adrenal physiology. The comparison of the adrenocortical response of males and females to an ACTH challenge provided new information about the amplitude and the timing of such a response and the excretion of glucocorticoids in both sexes. We demonstrated for the first time in the Syrian hamster that adrenocortical activity can be monitored in fecal samples in a noninvasive way. Our study provides a humane, practical, and noninvasive alternative to blood removal and therefore a powerful tool for stress-related studies in a species frequently used as an animal model in medical research.

Serine protease activity, bovine sperm protease, 66 kDa (BSp66), is present in hamster sperm and is involved in sperm-zona interaction.

Bovine sperm protease, 66 kDa (BSp66) is a serine protease previously characterized in bovine spermatozoa. Like other proteases, it may be present in sperm from other mammalian species different from bovine, playing a role in the fertilization process. In this study, we looked for BSp66 in hamster spermatozoa using heterologous antibodies against bovine BSp66. An immunoreactive protein was detected by Western blotting in mature and immature sperm. The detected protein had two isoforms similar to the ones reported in bovine sperm. Furthermore, indirect immune detection by fluorescence and electron microscopy assays, showed BSp66 signal at the acrosomal region similar to bovine sperm. As it was determined in bovine sperm, the acrosomal reaction displays the antigen within the acrosomal content. When live hamster sperm was incubated with polyclonal antibody against bovine BSp66 a decrease in the number of sperm bound to zona pellucida in homologous IVF and an impairment of head-head agglutination, were observed. These results suggest that a protease homologous to bovine BSp66 is present in golden hamster spermatozoa, with a conserved molecular mass and cellular location. Moreover, hamster BSp66 is probably involved in zona pellucida recognition.

Pigment cholelithiasis induced by vitamin A and its prevencion by butylated hydroxytoluene

We previously reported on the induction by vitamin A of gallstones, rich in calcium and phosphate, in hamsters. On the other hand, it has been reported that the phenolic antioxidant butylate hydroxytoluene (BHT) potentiates the hepatotoxicity of vitamin A. In the present work we have tested the effect of BHT on the lithogenicity of vitamin A and on bile composition. The urinary excretion of calcium and phosphate was determined to assess a possible asymptomatic bone resorptin due to vitamin A toxicity, and/or an effect of BHT on the homeostasis of calcium and phosphate. Theree groups of 18 male hamsters were fed with the following diets for 70 days: Group 1, Purina Nutricubes (DB); Group 2, DB + 25,000 IU percent retinol acetate (DL); group 3, DL + 500 mg percent BHT. Vitamin A (group 2) induced gallstones in 78 percent of the animals, increased bile flow and biliary phosphate and calcium concentrations, and reduced those of bili salt, cholesterol and phospholipid. BHT (Group 3) reduced gallstone frequency to 5.5 percent, and decreased biliary phosphate, calcium and lipids toward more normal concentrations. Vitamin A alone or with BHT did not significantly affect food intake or urinary excretion of calcium and phosphate

Efecto del ácido quenodesoxicólico sobre la composición de los ácidos biliares en bilis de hámster / Effect of chenodeoxycholic acid on the composition of biliary bile acids in hamster

Se investiga la modificación en la composición de los ácidos biliares de hámster por administración de altas dosis de ácido quenodeoxicólico (CDCA). Treinta hámster dorados, machos, fueron divididos en 5 grupos, uno de control y los otros cuatro recibieron 0,5g y 1g de CDCA por 100g de dieta estándar, durante 30 y 60 días. Luego de anestesia con éter se extrajo la vesícula y se aspiró la bilis inmediatamente. Los ácidos biliares se determinaron por cromatografía líquida de alta resolución (HPLC). Los conjugados del CDCA y del ácido litocólico (LCA) mostraron aumentos no relacionados con la dosis o el tiempo de tratamiento. También se observó un aumento moderado de los ceto derivados del CDCA, especialmente, uno de los glico conjugados. La relación cólico/queno disminuyó significativamente. Los ácidos taurolitocólico (TLCA) y glicolitocólico (GLCA) aumentaron significativamente en todos los grupos tratados. La relación glico/tauro conjugados de 1,17 en los controles aumentó a aproximadamente 3,0 en los tratados. Con respecto a la relación G/T del LCA de 0,38 en el grupo control aumentó a un valor cercano a 2,0 en los tratados.

Efecto del ácido quenodesoxicólico sobre la composición de los ácidos biliares en bilis de hámster / Effect of chenodeoxycholic acid on the composition of biliary bile acids in hamster

Se investiga la modificación en la composición de los ácidos biliares de hámster por administración de altas dosis de ácido quenodeoxicólico (CDCA). Treinta hámster dorados, machos, fueron divididos en 5 grupos, uno de control y los otros cuatro recibieron 0,5g y 1g de CDCA por 100g de dieta estándar, durante 30 y 60 días. Luego de anestesia con éter se extrajo la vesícula y se aspiró la bilis inmediatamente. Los ácidos biliares se determinaron por cromatografía líquida de alta resolución (HPLC). Los conjugados del CDCA y del ácido litocólico (LCA) mostraron aumentos no relacionados con la dosis o el tiempo de tratamiento. También se observó un aumento moderado de los ceto derivados del CDCA, especialmente, uno de los glico conjugados. La relación cólico/queno disminuyó significativamente. Los ácidos taurolitocólico (TLCA) y glicolitocólico (GLCA) aumentaron significativamente en todos los grupos tratados. La relación glico/tauro conjugados de 1,17 en los controles aumentó a aproximadamente 3,0 en los tratados. Con respecto a la relación G/T del LCA de 0,38 en el grupo control aumentó a un valor cercano a 2,0 en los tratados. (AU)

Steroid hormone receptors and the sexual phenotype of the Harderian gland in hamsters.

To investigate the participation of intracellular steroid hormone receptors in the sexual transformation process of the Harderian gland, a series of experiments were undertaken in adult golden hamsters. The invitro labelling of cytosolic steroid-binding sites with appropriate radioligands revealed the presence of androgen, oestrogen and glucocorticoid but not progestin receptors in the glands from animals of both sexes. The androgen receptor of the female gland was further characterized because it was found to be the predominant intracellular steroid receptor. Studies of binding kinetics using [3H]7 alpha,17 alpha-dimethyl-17 beta-hydroxy-4-oestren-3-one (DMNT) as ligand, demonstrated a high affinity androgen-binding site with an apparent dissociation constant (Kd) of 0.7 nmol/l and maximal saturation binding capacity of 84.0 +/- 3.0 (S.D.) fmol/mg protein. Specificity of the androgen receptor was assessed by displacement analysis; DMNT, 5 alpha-dihydrotestosterone, testosterone and 3 alpha-androstanediol were efficient competitors for the androgen-binding site, while oestradiol-17 beta, progesterone and dexamethasone exhibited very little, if any, competitive potency. The sedimentation coefficient of the androgen receptor in sucrose density gradients was 8-9 S. These data indicate that the physicochemical characteristics of the androgen receptor from the female gland are similar to those previously described in the male gland. The striking observation of a complete lack of oestrogen-inducible and oestrogen-insensitive progestin receptors in glands cytosol, even after stimulation with cholera toxin, adds further support to the concept that the androgen receptor is the key molecule mediating the hormone-induced sexual transformation of the Harderian gland in this species.