An enhanced quantitative assay for chiro-inositol concentration can be used to determine insulin-resistance, or a predeposition to the development of insulin-resistance, in type I and type II diabetics. Spot urine or serum samples reflecting concentrations of chiro-inositol below about 1.0 micrograms/ml in urine or 0.1 micrograms/ml in serum are indicative of a predisposition to the development of insulin-resistance, while concentrations below about 0.3 micrograms/ml or 0.03 micrograms/ml in serum are associated with actual insulin-resistance symptoms. The assay can be employed for patient diagnosis, insulin therapy monitoring, and family screening.
This application is a continuation of application Ser. No. 07/476,953, filed on Feb. 8, 1990, now abandoned; which is a CONT-IN-PART of 07/320,485, filed on Mar. 8, 1989, abandoned for Continuation of 07/751,628 of Aug. 26, 1991, pending.
Antibodies raised against derivatives of inositol are used to assay for specific isomers of inositol in a sample by first converting any inositol present in the sample to the derivative that was used to raise the antibody and then conducting an immunoassay for the inositol derivative in a conventional manner.
The present invention relates to an assay method of chiroinositol which comprises reacting a specimen containing chiroinositol with 1) a dehydrogenase, which catalyses at least reversible reaction with a substrate of chiroinositol in the presence of a coenzyme selected from NAD(P)s and a coenzyme selected from thio-NAD(P)s, 2) A1 and 3) B1 to form cycling reaction of the formula ##STR1## wherein a product is a compound, from which 2 or 4 hydrogen atoms are deleted from chiroinositol, A1 is NAD(P)s or thio-NAD(P)s, A2 is a reduced form of A1, B1 is a reduced form of NAD(P)s in case of A1 being thio-NAD(P)s or a reduced form of thio-NAD(P)s in case of A1 being NAD(P)s and B2 is an oxidized form of B1, and determining an amount of converted A2 or B1 by the said reaction, and a composition for assay of chiroinositol. Chiroinositol can be assayed by accurate, simple, low price and high sensitive method.
An enhanced quantitative assay for chiro-inositol concentration can be used to determine insulin-resistance, or a predisposition to the development of insulin-resistance, in type I and type II diabetics. Spot urine or serum samples reflecting concentrations of chiro-inositol below about 1.0 micrograms/ml in urine or 0.1 micrograms/ml in serum are indicative of a predisposition to the development of insulin-resistance, while concentrations below about 0.3 micrograms/ml or 0.03 micrograms/ml in serum are associated with actual insulin-resistance symptoms. The assay can be employed for patient diagnosis, insulin therapy monitoring, and family screening.
The present invention provides a new method for screening for insulin resistance that utilizes both myoinositol and chiroinositol as indicators. According to this method, levels of myoinositol and D-chiroinositol are measured. The value of the concentration of myoinositol is divided by that of D-chiroinositol to give a "myo/chiro ratio." The value of this ratio is compared with a value that is characteristic of insulin resistance. If the characteristic value is equaled or exceeded, insulin resistance is indicated.
