Diagnostic uses of IGFBP-2

Abstract

A method for determining a concentration of IGF-I that defines a therapeutically effective dose of IGF-I, i.e., a dose that will provide a therapeutic response in the treatment of neurological disorders for which IGF-I is utilized (including peripheral neuropathy, diabetic neuropathy, post-polio syndrome, small fiber neuropathy, ALS, and MS) is described. The method comprises determining whether a particular dose of IGF-I causes a 1.5 fold or greater increase in the homeostatic concentration of plasma IGFBP-2 in a mammal that has previously received a defined dose of IGF-I. The method of the invention can also be used to determine whether or not biological tolerance has developed to a particular dose of IGF-I.

What is claimed is: 
     
       1. A method for determining a therapeutically effective dose of IGF-I in a mammal comprising; a) measuring homeostatic IGFBP-2 concentration in said mammal;   b) administering a dose of IGF-I to be tested to said mammal at least once daily for a period of at least 7 days;   c) administering a final dose of said dose of IGF-I to be tested to said mammal on the day following said period;   d) measuring post-treatment IGFBP-2 in said mammal from at least about 0.5 to at least about 10 hours following said final dose; and   e) determining whether post-treatment IGFBP-2 concentration increased 1.5 fold or greater over homeostatic IGFBP-2 concentration for said mammal.   
     
     
       2. A method for screening a mammal receiving a therapeutically effective dose of IGF-I as determined according to claim 1 to determine whether said mammal has become tolerant to said dose of IGF-I comprising; a) measuring post-treatment IGFBP-2 concentration in said mammal from at least about 0.5 to at least about 10 hours following said therapeutically effective dose of IGF-I; and   b) determining whether post-treatment IGFBP-2 concentration increased 1.5 fold or greater over homeostatic IGFBP-2 concentration for said mammal.