Selective tonic inhibition of G-6-Pase catalytic subunit, but not G-6-P transporter, gene expression by insulin in vivo.

نویسندگان

  • L A Hornbuckle
  • D S Edgerton
  • J E Ayala
  • C A Svitek
  • J K Oeser
  • D W Neal
  • S Cardin
  • A D Cherrington
  • R M O'Brien
چکیده

The regulation of glucose-6-phosphatase (G-6-Pase) catalytic subunit and glucose 6-phosphate (G-6-P) transporter gene expression by insulin in conscious dogs in vivo and in tissue culture cells in situ were compared. In pancreatic-clamped, euglycemic conscious dogs, a 5-h period of hypoinsulinemia led to a marked increase in hepatic G-6-Pase catalytic subunit mRNA; however, G-6-P transporter mRNA was unchanged. In contrast, a 5-h period of hyperinsulinemia resulted in a suppression of both G-6-Pase catalytic subunit and G-6-P transporter gene expression. Similarly, insulin suppressed G-6-Pase catalytic subunit and G-6-P transporter gene expression in H4IIE hepatoma cells. However, the magnitude of the insulin effect was much greater on G-6-Pase catalytic subunit gene expression and was manifested more rapidly. Furthermore, cAMP stimulated G-6-Pase catalytic subunit expression in H4IIE cells and in primary hepatocytes but had no effect on G-6-P transporter expression. These results suggest that the relative control strengths of the G-6-Pase catalytic subunit and G-6-P transporter in the G-6-Pase reaction are likely to vary depending on the in vivo environment.

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Selective stimulation of G-6-Pase catalytic subunit but not G-6-P transporter gene expression by glucagon in vivo and cAMP in situ.

We recently compared the regulation of glucose-6-phosphatase (G-6-Pase) catalytic subunit and glucose 6-phosphate (G-6-P) transporter gene expression by insulin in conscious dogs in vivo (Hornbuckle LA, Edgerton DS, Ayala JE, Svitek CA, Neal DW, Cardin S, Cherrington AD, and O'Brien RM. Am J Physiol Endocrinol Metab 281: E713-E725, 2001). In pancreatic-clamped, euglycemic conscious dogs, a 5-h ...

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عنوان ژورنال:
  • American journal of physiology. Endocrinology and metabolism

دوره 281 4  شماره 

صفحات  -

تاریخ انتشار 2001