Glucose-6-phosphate Metabolic Preferential Destinations in Bovine Oviduct Cells

Acta Scientiae Veterinariae

Endereço:
AV BENTO GONçALVES 9090
PORTO ALEGRE / RS
Site: http://www.ufrgs.br/actavet/
Telefone: (51) 3308-6964
ISSN: 16799216
Editor Chefe: [email protected]
Início Publicação: 31/12/1969
Periodicidade: Trimestral
Área de Estudo: Medicina Veterinária

Glucose-6-phosphate Metabolic Preferential Destinations in Bovine Oviduct Cells

Ano: 2010 | Volume: 38 | Número: 4
Autores: Helga Gomes, Angelo José Burla Dias, Jorge Moraes, Carla Sobrinho Paes de Carvalho, Carlos Logullo
Autor Correspondente: Helga Gomes | [email protected]

Palavras-chave: oviduct, glucose-6-phosphate, energy metabolism, glucose, glycogen

Resumos Cadastrados

Resumo Inglês:

Background: The oviduct is a dynamic organ which facilitates gamete function, fertilization and embryo development. This
organ is covered by an epithelium containing ciliated and non-ciliated cells. Secretions of non-ciliated cells compose the
oviduct fluid, which will nourish the early embryo. During the period of ovulation, the oviduct exhibits an active role, where
the lumen provides an environment suitable for fertilization and the muscle layer contracts rhythmically to move the egg
toward the uterus. In this study we aimed to investigate the content of fuel metabolites and enzyme activity assays related to
the glycolytic metabolism in bovine oviduct cells such as Glucose-6-phosphate, Glycogen, Pyruvate, Hexokinase, Pyruvate
kinase, Phosphoenolpyruvate carboxykinase and Glucose-6-phosphate dehydrogenase.
Materials, Methods & Results: In this sense, we divided the oviduct in 3 identical portions (anterior, medium and posterior).
After division, each region was massaged and the lumen was flushed with 2mL Ca+2, and Mg+2 free PBS, pH 7.2. The material
obtained was centrifuged at 3.000 x g for 5 min at 4ºC. The pellet of cells were ressuspended again with 2 mL of Ca+2 and Mg+2
free PBS at pH 7.2 and sonicated 6 times at 60W. All the assays were performed in a Shimadzu U1240 spectrophotometer. The
data were normalized in terms of total protein content and the assay was ran in triplicate. In the anterior region a low activity
of hexokinase (HK) and pyruvate kinase (PK) and an accumulation of pyruvate were detected. Besides this, based on the
glucose-6-phosphate dehydrogenase (G6PDH) activity and the amount of glycogen, the glucose-6-phosphate (G6P) could be
directed to the pentose phosphate pathway, which provides protection against the toxicity of reactive oxygen species (ROS)
and supplies NADPH to be used in anabolic pathways. In the oviduct’s medium portion we observed an intense glycolytic
metabolism based on HK and PK activities and low pyruvate levels that could be exported to compose the lumen fluid. In the
oviduct’s posterior region we detected a different metabolic profile with high gluconeogenic activity due to elevated
phosphoenolpyruvate carboxykinase (PEPCK) activity glucose-6-phosphate concentration and HK activity.
Discussion: Low HK and PK activities were observed in the anterior portion, which could be due to the concentration of
pyruvate, Besides this, the (G6PDH) activity, assessed together with its substrate and the amount of glycogen, suggests that
cells from the anterior portion are working for the energetic maintenance of whole oviduct cells. The medium portion presents
a metabolism via high HK and PK activities. An increase in PEPCK activity could be considered as a source of
phosphoenolpyruvate. Accumulation of glycogen, high concentration of G6-P and (G6PDH) activity are also observed. The
profile of enzymes from glycolytic and gluconeogenic pathways and their substrate together with (G6PDH) activity and G6-
Phosphate lead us to believe that the preferential product produced in the posterior region is pyruvate.