Recombinant human insulin-like growth factor binding protein-3 (rhIGFBP-3): effects on the glycemic and growth promoting activities of rhIGF-1 in the rat

Growth Regul. 1993 Mar;3(1):50-2.


The effects of IGFBPs on IGF-1 bioactivity in vivo remain largely unknown. We have tested the ability of rhIGFBP-3, made in 293 cells or CHO cells, to affect the glycemic and anabolic activities of co-administered rhIGF-1. For glycemic studies female dw/dw rats were anesthetized, a jugular catheter inserted, basal blood samples taken and i.v. injections given of rhIGF-1 (0.25 mg/kg), rhIGFBP-3 (0.50 mg/kg), or rhIGF-1 plus rhIGFBP-3 (0.25 plus 0.50 mg/kg, respectively). The blood glucose (20 min later, as a percent of initial, mean +/- SD) reached its nadir for rhIGF-1 alone (58 +/- 5%) but was not changed by rhIGFBP-3 alone (99 +/- 4%) or rhIGF-1 plus rhIGFBP-3 (93 +/- 5%). In growth studies, young female hypophysectomized rats (90-105 g) were injected s.c. twice daily for 3-4 days, or infused s.c. for 7 days, with excipient, rhIGF-1 or rhIGF-1 plus rhIGFBP-3 at doses similar to those used in the hypoglycemia studies. Weight gain induced by rhIGF-1 was either unchanged, or enhanced, when the rhIGF-1 was delivered with rhIGFBP-3. The hypoglycemic activity of IGF-1 was greatly reduced if IGF-1 was administered bound to 293-cell rhIGFBP-3 but anabolic activity was unchanged or enhanced.

MeSH terms

  • Animals
  • Blood Glucose / metabolism*
  • Body Weight / drug effects
  • Carrier Proteins / pharmacology*
  • Dose-Response Relationship, Drug
  • Female
  • Growth / drug effects*
  • Growth Inhibitors / pharmacology*
  • Humans
  • Hypophysectomy
  • Insulin-Like Growth Factor Binding Proteins
  • Insulin-Like Growth Factor I / antagonists & inhibitors*
  • Insulin-Like Growth Factor I / pharmacology
  • Rats
  • Recombinant Proteins / pharmacology


  • Blood Glucose
  • Carrier Proteins
  • Growth Inhibitors
  • Insulin-Like Growth Factor Binding Proteins
  • Recombinant Proteins
  • Insulin-Like Growth Factor I