Competitive particle concentration fluorescence immunoassays for measuring anti-diabetic drug levels in mouse plasma.

Two competitive particle concentration fluorescence immunoassays were developed to measure blood levels of analogs of anti-diabetic drugs being tested in diabetic mice. Ligands that contained the active pharmacophores were conjugated to PPD for immunization and to beta-phycoerythrin for use as a tracer in the immunoassays. Approximately 90% of 262 compounds assayed were detectable at less than 120 nM in plasma which was well below the estimated therapeutic level of 1 microM for lowering blood glucose.

Monoclonal antibodies as surrogate receptors in a high throughput screen for compounds that enhance insulin sensitivity.

Monoclonal antibodies (MoAbs) were made to a known insulin sensitivity enhancer (ISE) compound, CS-045. The MoAbs were characterized with respect to binding other known thiazolidinedione ISE compounds using a CS-045 labeled with b-phycoerythrin in a competitive particle concentration fluorescence immunoassay (PCFIA). By comparing the rank order of IC50 values for each compound to its respective potency as an ISE, one MoAb (13E3) was selected for further characterization.

Compound M & B 39890A [N-(3-imidazol-1-ylpropyl)- 2-(3-trifluoromethylbenezensulphonamido)-benzamide hydrochloride], a glucagon and insulin secretion inhibitor, improves insulin sensitivity in viable yellow obese-diabetic mice.

Compound M & B 39890A [N-(3-imidazol-1-ylpropyl)-2- (3-trifluoromethylbenzenesulphonamido)benzamide hydrochloride] had no effect on cellular cAMP and cGMP levels but significantly inhibited insulin and glucagon secretion from freshly isolated normal rat islets stimulated with 10 mM glucose and 20 mM arginine. Daily gavage of the compound for three days lowered the elevated blood glucose and plasma insulin levels in fed, male viable yellow obese-diabetic mice; the minimum effective dose was 25 mg/kg. However, M & B 39890A did not affect the blood glucose level of fasted diabetic mice.