Reprod. Nutr. Dev.
Volume 46, Number 3, May-June 2006
|Page(s)||257 - 272|
|Published online||30 May 2006|
Prenatal developmental changes in glucose transporters, intermediary metabolism and hormonal receptors related to the IGF/insulin-glucose axis in the heart and adipose tissue of bovinesJean-François Hocquettea, Helga Sauerweinb, Yumi Higashiyamac, Brigitte Picarda and Hiroyuki Abed
a INRA, Herbivore Research Unit, Muscle Growth and Metabolism Team, Theix, 63122 Saint-Genès-Champanelle, France
b Institute for Animal Sciences, Physiology and Hygiene Group, University of Bonn, 53115 Bonn, Germany
c Pasture and Grazing Management Laboratory, National Agricultural Research Centre for Tohoku Region, Akahira 4, Shimo-kuriyagawa, Morioka, Iwate, 020-0198, Japan
d National Institute of Livestock and Grassland Science, Ikenodai-2, Tsukuba, Ibaraki, 305-0901 Japan
(Received 7 November 2005; accepted 28 February 2006; published online 13 June 2006)
Abstract - Glucose transporter ontogenesis is likely to play a key role in glucose uptake by foetal tissues in order to satisfy their energy requirements. We thus investigated developmental changes in the bovine heart and perirenal adipose tissue in two glucose transporter isoforms, namely GLUT1 and GLUT4, the latter being responsible for the regulation of glucose uptake by insulin. Other key players of the glucose/insulin axis were also assessed. Plasma glucose concentration in the foetus was lower at 8 and 8.5 months of age than previously. In the heart, GLUT1 protein level markedly decreased between 3 and 4 months of age, whereas the number of insulin and IGF-I binding sites continually decreased, especially between 7 and 8 or 8.5 months of age. On the contrary, the GLUT4 level increased until 8 months of age and remained high until 2 weeks after birth. The activities of enzymes of glucose metabolism (namely phosphofructokinase [PFK] and lactate dehydrogenase [LDH]) increased throughout gestation and reached a plateau at 6 and 8.5 months of age for PFK and LDH, respectively. The activities of enzymes involved in fatty acid metabolism increased especially at birth. In perirenal adipose tissue, high mitochondrial activity was detected before birth which is a characteristic of brown adipose tissue. Furthermore, lipoprotein lipase activity and GLUT4 protein level markedly increased to reach a maximum at 6-7 and 8 months of age, and sharply decreased thereafter, whereas GLUT1 protein level increased between 6 and 7 months of age. In conclusion, considerable changes in the regulation of the insulin/glucose axis were observed from 6 months onwards of foetal development in both the heart and adipose tissue of cattle, which probably alters the potential of these tissues to use glucose or fat as energy sources.
Key words: glucose transporter / heart / adipose tissue / bovine / foetal development
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© INRA, EDP Sciences 2006