NPY Indirect Antibody ELISA. NPY measured in the insulin injection groups decreased 18% and in the glucagon injection groups increased 50% when compared to NPY levels of controls injected with PBS. Indirect antibody ELISA was performed according to the procedures of Kirkegaard & Perry Laboratories, Inc., using rabbit anti-NPY antibody. The NPY levels were determined through color intensity by measuring OD reading at 405 nm using a Perkin Elmer Wallac 1420 VICTOR3 Multilabel Counter. Results are expressed as the mean ± SD of assays of the brain extracts from four independent animals. Each extract was assayed in duplicate. For negative controls, the samples were not reacted with primary anti-NPY antibody. The net OD values for samples were obtained by subtracting the individual values with negative control values. The average of net OD values were converted into % change in NPY levels relative to PBS control and is plotted. A one-way analysis of variance revealed significant differences between the groups [F(3,12) = 4.13, p = 0.031].