Used to measure nitric oxide synthase 3 (NOS3) enzyme activity in rat biological samples such as tissue homogenates, cell lysates, and serum. This kit is commonly applied in cardiovascular and endothelial function research, where NOS3 plays a key role in producing nitric oxide, a critical signaling molecule for blood vessel dilation and vascular health. Researchers use this assay to evaluate changes in NOS3 activity under experimental conditions, including hypertension, diabetes, ischemia, and drug treatments. The ELISA format allows for high-throughput, quantitative analysis with good sensitivity and specificity, making it suitable for both basic research and preclinical studies involving rat models.