Increases in hepatic fructose-2,6-bisphosphate level and fructose-6-phosphate,2-kinase activity in rats with ventromedial lesions of the hypothalamus

Yuya Yamada*, Takao Shimizu, Naoko Hara, Ikuo Mineo, Masanori Kawachi, Hiroaki Kiyokawa, Kentaro Yamada, Shigenori Fujioka, Yuji Matsuzawa, Norio Kono, Seiichiro Tarui

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

To investigate altered fructose-2,6-bisphosphate (fructose-2,6-P 2 )metabolism, we measured fructose-2,6-P 2 levels and fructose-6-phosphate,2-kinase (fructose-6-P,2-kinase) activities in various tissues, including liver, kidney, heart, and skeletal muscle, of ventromedial hypothalamus (VMH)-lesioned rats during feeding and starvation. The plasma insulin level was 6 times or more higher in these rats than in the controls. The fructose-2,6-P 2 level in liver was much greater in VMH-lesioned rats than in the controls: 15.1±2.2 nmol/g tissue versus 7.7±0.7 in the fed state, 5.3±1.1 versus 1.6±0.4 in the starved state. In kidney, heart, and skeletal muscle, fructose-2,6-P 2 levels were not different between the two animal groups. The activity of hepatic fructose-6-P,2-kinase remained high after 20 h of starvation in VMH-lesioned rats, whereas it was decreased markedly in the controls. The hepatic concentration of fructose-6-phosphate was also high in VMH-lesioned rats. Both fructose-6-P,2-kinase activity and fructose-6-phosphate concentration in the liver of starved VMH-lesioned rats were comparable to those of control rats in fed conditions. These results indicate that the alteration of fructose-2,6-P 2 metabolism is characteristic of liver in VMH-lesioned rats, and that the increase in hepatic fructose-2,6-P 2 may activate hepatic glycolysis not only during feeding but also during starvation, leading to the enhanced lipogenesis in these obese rats.

Original languageEnglish (US)
Pages (from-to)576-579
Number of pages4
JournalJournal of Biochemistry
Volume104
Issue number4
DOIs
StatePublished - Jan 1 1988

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology

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