IGF alters jejunal glucose transporter expression and serum glucose levels in immature rats

Robert H. Lane, Bohuslav Dvorak, Nicole K. MacLennan, Katerina Dvorakova, Melissa D. Halpern, Tho D. Pham, Anthony F. Philipps

Research output: Contribution to journalArticlepeer-review

31 Scopus citations


Milk-borne insulin-like growth factors (IGFs) enhance nutrient absorption in the immature intestine, which is characterized by low levels of glucose oxidation. We therefore hypothesized that feeding a rat milk substitute (RMS) devoid of growth factors to rat pups would lower serum glucose levels relative to dam-fed control rats and that supplementation of RMS with physiological doses of either IGF-I or IGF-II would normalize serum glucose levels via increased jejunal glucose transporter 2 (GLUT2) and high-affinity Na+-glucose cotransporter (SGLT1) expression. We found lower serum glucose concentrations in RMS-fed pups; in contrast, serum glucose levels in the IGF-supplemented pups were similar to those of dam-fed controls. RT-PCR and laser scanning confocal microscopy similarly demonstrated that IGF supplementation increased expression of jejunal glucose transporters. Further experiments demonstrated that IGF supplementation altered mRNA levels of key mitochondrial enzymes without altering jejunal lactase activity. We conclude that IGF-I and IGF-II supplementation increases serum glucose levels in the immature rat pup fed artificial formula and alters gene expression of the jejunal glucose transporters.

Original languageEnglish (US)
Pages (from-to)R1450-R1460
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Issue number6 52-6
StatePublished - Dec 1 2002


  • Fatty acid oxidation
  • GLUT1
  • GLUT2
  • Glucose oxidation
  • SGLT1

ASJC Scopus subject areas

  • General Medicine


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