PT  - JOURNAL ARTICLE
AU  - Ratan V. Bhat
AU  - Thomas M. Engber
AU  - Yuan Zhu
AU  - Matthew S. Miller
AU  - Patricia C. Contreras
TI  - Identification of Insulin-Like Growth Factor Binding Protein-2 as a Biochemical Surrogate Marker for the <em>in Vivo</em> Effects of Recombinant Human Insulin-Like Growth Factor-1 in Mice
DP  - 1997 Apr 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 522--530
VI  - 281
IP  - 1
4099  - http://jpet.aspetjournals.org/content/281/1/522.short
4100  - http://jpet.aspetjournals.org/content/281/1/522.full
SO  - J Pharmacol Exp Ther1997 Apr 01; 281
AB  - Recent studies indicate that a daily s.c. injection of 1 mg/kg of recombinant human insulin-like growth factor-1 (rhIGF-1) for 17 days is efficacious in enhancing the functional recovery of injured sciatic nerves in CD-1 mice. To identify and characterize surrogate marker(s) that are altered in association with the administration of an efficacious dose of rhIGF-1, dose-response curves (0.1, 1 and 10 mg/kg) and time course effects (0, 0.5, 3, 6 and 24 hr) were determined after acute (single) and chronic (once daily for 17 days) injections of rhIGF-1 in CD-1 mice. Plasma glucose levels decreased in a dose-dependent fashion after either acute or chronic injections of rhIGF-1 with maximal effects at 0.5 to 1 hr after administration of rhIGF-1. Among the three insulin-like growth factor binding proteins (IGFBPs) evaluated in the study, only IGFBP2 levels were consistently increased in a dose-dependent fashion with maximal effects 3 hr after the last of a series of injections of rhIGF-1. Furthermore, IGFBP2 levels increased at a dose of rhIGF-1 (1 mg/kg) that enhances the regeneration of injured sciatic nerves in mice. Chronic administration of insulin at doses that cause comparable decreases in plasma glucose to that of rhIGF-1 did not alter IGFBP2 levels or enhance hindlimb function suggesting that the beneficial effects of rhIGF-1 occur via activation of the type-I IGF receptor rather than the insulin receptor. Based on these criteria, IGFBP2 appears to be useful as a surrogate marker for determining the in vivo effects of rhIGF-1. The American Society for Pharmacology and Experimental Therapeutics