Influência hormonal sobre o sistema pigmentar em Eupemphix nattereri (Anura): efeitos do alpha-MSH, estradiol e testosterona
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2010-06-01
Autores
Zieri, Rodrigo [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Os vertebrados ectotérmicos apresentam um desenvolvido sistema de células com pigmentos melânicos em seu citoplasma, localizado em diversos órgãos e membranas. A dispersão dos grãos de melanina dentro dos melanócitos responde fortemente à exposição ao hormônio estimulante de melanócitos (MSH) e aos hormônios sexuais, promovendo alteração na coloração. Este trabalho buscou avaliar o efeito dos esteróides cipinato de testosterona, 17 β-estradiol e do MSH sobre a pigmentação hepática e testicular de Eupemphix nattereri, mediante análise histológica, e ultra-estrutural. Foram coletados 60 machos adultos na região de São José do Rio Preto, SP. Para cada experimento, dez machos adultos receberam doses subcutâneas contendo 0,5 mg/kg de cipionato de testosterona e 0,5 mg/kg de 17 β-estradiol, dissolvidos em óleo vegetal e, 2,5x10-7 mmol/10g de α-MSH dissolvido em PBS, durante 7 dias, a cada 48h. O grupo controle recebeu apenas óleo vegetal ou PBS. Grupos com cinco animais foram eutanasiados 24h após do término do tratamento, e outros cinco, após 15 dias. Foram realizados estudos morfológicos utilizando microscopia de luz e microscopia eletrônica de transmissão. No tecido hepático foram encontradas células de Kupffer. No interstício testicular observou-se melanócitos, com inúmeros melanossomos. Para o grupo tratado com cipionato de testosterona, foi observado um aumento de aproximadamente 2x na área ocupada pelas células pigmentadas no fígado e 4x nos testículos mediante analise a curto prazo. Para o mesmo tratamento, foi observado aumento de 1,8x no fígado dos animais eutanasiados após 15 dias. Tal resposta pode ser decorrente do aumento da atividade melanossintética, do aumento do número de células, ou ambos. Os animais tratados com 17 β-estradiol e α- MSH não apresentaram alterações na pigmentação hepática e testicular mediante...
Ectothermic vertebrates have a well-developed system of melanin-containing cells, which are distributed throughout several organs and tissues. The dispersion of melanin-containing granules within melanocytes responds to prolonged exposure to high concentration of MSH and sexual hormones inducing color change. The present study aimed to characterize morphological and stereological patterns of pigmented cells in liver and testis of the Eupemphix nattereri under effect of testosterone cypionate, 17 β-estradiol and α-MSH. Sixty adult males were collected in São José do Rio Preto, São Paulo State, Brazil. For each experiment, ten adult males were treated with the following hormones injected in the dorsal lymph sac during seven days: (1) 5 mg/kg dose of testosterone cypionate or (2) 5 mg/kg dose of 17 β-estradiol (dissolved in vegetal oil) or (3) 2,5x10-7 mmol/10g of α-MSH (dissolved in PBS). The control group received only vegetal oil or PBS solution at the same hormonal concentration. Groups of five animals were euthanatized after 24h and the other five, after 15 days. Morphological studies with light and transmission electron microscopy were carried out in the groups. In the hepatic tissue were found Kupffer cells, which are characterized by multivesicle bodies in the cytoplasm and large amount of melanosomes. In the testis, melanocytes-like cells are present in the interstitium. They presented large and irregular aspect and a great amount of intensely pigmented cytoplasm. For the groups treated with testosterone cypionate an increase of approximately 2x in the occupied area by the pigmented cells in the liver and 4x in the testis was observed in the treatment group against the control. The observed response can be due to increase of melanosynthesis Introdução 3 Zieri et al., 2010 activity, increase in the number of pigmented cells, or both. Moreover, for the same treatment... (Complete abstract click electronic access below)
Ectothermic vertebrates have a well-developed system of melanin-containing cells, which are distributed throughout several organs and tissues. The dispersion of melanin-containing granules within melanocytes responds to prolonged exposure to high concentration of MSH and sexual hormones inducing color change. The present study aimed to characterize morphological and stereological patterns of pigmented cells in liver and testis of the Eupemphix nattereri under effect of testosterone cypionate, 17 β-estradiol and α-MSH. Sixty adult males were collected in São José do Rio Preto, São Paulo State, Brazil. For each experiment, ten adult males were treated with the following hormones injected in the dorsal lymph sac during seven days: (1) 5 mg/kg dose of testosterone cypionate or (2) 5 mg/kg dose of 17 β-estradiol (dissolved in vegetal oil) or (3) 2,5x10-7 mmol/10g of α-MSH (dissolved in PBS). The control group received only vegetal oil or PBS solution at the same hormonal concentration. Groups of five animals were euthanatized after 24h and the other five, after 15 days. Morphological studies with light and transmission electron microscopy were carried out in the groups. In the hepatic tissue were found Kupffer cells, which are characterized by multivesicle bodies in the cytoplasm and large amount of melanosomes. In the testis, melanocytes-like cells are present in the interstitium. They presented large and irregular aspect and a great amount of intensely pigmented cytoplasm. For the groups treated with testosterone cypionate an increase of approximately 2x in the occupied area by the pigmented cells in the liver and 4x in the testis was observed in the treatment group against the control. The observed response can be due to increase of melanosynthesis Introdução 3 Zieri et al., 2010 activity, increase in the number of pigmented cells, or both. Moreover, for the same treatment... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Anuro - Morfologia, Estradiol, Testosterona, Células pigmentares viscerais, Eupemphix nattereri, Anuran, Melanocyte, Melanomacrophages, Melanin
Como citar
ZIERI, Rodrigo. Influência hormonal sobre o sistema pigmentar em Eupemphix nattereri (Anura): efeitos do alpha-MSH, estradiol e testosterona. 2010. 96 f. Tese (doutorado) - Universidade Estadual Paulista, Instituto de Biociências, Letras e Ciências Exatas, 2010.