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Abstract(s)
As células de Sertoli (SCs) possuem a capacidade fenomenal de fornecerem fatores de crescimento e nutrientes às células da linha germinativa. Apesar de consumirem vários tipos de substratos, incluindo aminoácidos como a glutamina, as SCs preferencialmente metabolizam glucose. Ao fazê-lo, estas células produzem grandes quantidades de lactato, aquele que é considerado pela maioria dos autores, o substrato preferencial das células germinativas. A Regucalcina (RGN) é uma proteína de ligação ao cálcio expressa nas SCs e que estudos anteriores associaram à regulação do metabolismo celular. Neste trabalho, avaliou-se a metabolização de glucose e glutamina nas SCs de ratos transgénicos que sobre expressam regucalcina (Tg-RGN) e dos seus homólogos wild-type (Wt). Dos testículos destes animais procedeu-se ao isolamento de SCs primárias, que foram mantidas em cultura durante 24 horas. No final deste período experimental foram analisados vários parâmetros metabólicos, tais como a expressão proteica e atividade de vários intervenientes na glicólise e glutaminólise. Observou-se que, apesar de consumirem menos glucose, as SCs dos animais Tg-RGN produzem e exportam mais lactato. Estas observações foram concomitantes com o aumento da expressão de alanina aminotransferase e com o aumento da taxa de consumo/oxidação de glutamina, o que sugere a existência de vias alternativas à glucose a contribuirde forma significativa para o aumento da produção de lactato nas SCs dos ratos Tg-RGN. Os resultados obtidos demonstram um metabolismo distinto das SCs entre ratos Wt e Tg-RGN, o que alarga o espectro das possíveis funções da RGN ao nível da espermatogénese. Para além disso, as observações registadas demonstram a enorme plasticidade do metabolismo das SCs, uma característica que pode ser de extrema relevância no contexto da fertilidade masculina.
Sertoli cells (SCs) possess the outstanding capability to provide the germ line with growth factors and nutrients. Despite consuming several types of substrate, including amino acids such as glutamine, SCs preferentially metabolize glucose. By doing so, SCs produce high amounts of lactate, the substrate considered by most authors as the preferred of germ cells. Regucalcin (RGN) is a calcium binding protein expressed in the SCs that has been previously associated to the regulation of cell metabolism. On this dissertation we have evaluated glucose and glutamine handling in the SCs of transgenic rats overexpressing regucalcin (Tg-RGN) and their wild-type (Wt) homologous. Primary SCs were isolated from adult Wt and Tg-RGN animals and maintained in culture for 24 hours. Afterwards, several metabolic parameters, such as the protein expression of several metabolic intervenients, were analysed. We have observed that, despite consuming less glucose, the SCs of Tg-RGN animals produce and export more lactate. These observations were underpinned by increased expression of alanine transaminase and augmented rates of glutamine consumption/oxidation, which suggests the existence of alternative routes to glucose that significantly contribute to the available lactate pool in the SCs of Tg-RGN rats. The results obtained clearly present a completely distinct metabolic profile between the SCs of Tg-RGN and Wt animals, which widens the roles that RGN is likely to play in the control of spermatogenesis. Moreover, the registered observations display the enormous plasticity of SCs’ metabolism, a capacity that might be of extreme relevance in the context of male fertility.
Sertoli cells (SCs) possess the outstanding capability to provide the germ line with growth factors and nutrients. Despite consuming several types of substrate, including amino acids such as glutamine, SCs preferentially metabolize glucose. By doing so, SCs produce high amounts of lactate, the substrate considered by most authors as the preferred of germ cells. Regucalcin (RGN) is a calcium binding protein expressed in the SCs that has been previously associated to the regulation of cell metabolism. On this dissertation we have evaluated glucose and glutamine handling in the SCs of transgenic rats overexpressing regucalcin (Tg-RGN) and their wild-type (Wt) homologous. Primary SCs were isolated from adult Wt and Tg-RGN animals and maintained in culture for 24 hours. Afterwards, several metabolic parameters, such as the protein expression of several metabolic intervenients, were analysed. We have observed that, despite consuming less glucose, the SCs of Tg-RGN animals produce and export more lactate. These observations were underpinned by increased expression of alanine transaminase and augmented rates of glutamine consumption/oxidation, which suggests the existence of alternative routes to glucose that significantly contribute to the available lactate pool in the SCs of Tg-RGN rats. The results obtained clearly present a completely distinct metabolic profile between the SCs of Tg-RGN and Wt animals, which widens the roles that RGN is likely to play in the control of spermatogenesis. Moreover, the registered observations display the enormous plasticity of SCs’ metabolism, a capacity that might be of extreme relevance in the context of male fertility.
Description
Keywords
Células de Sertoli Espermatogénese Glucose Glutamina Metabolismo Regucalcina