Bivariate assay for cleaved atrial natriuretic factor (ANF(101-105/106-126)) in sheep plasma

A bivariate assay has been developed to measure both ANF, and cleaved ANF (ANF(101-105/106-126)) the primary product of endopeptidase-24.11 action on rat ANF(101-126). The assay employed two different antisera directed to the carboxy-terminal and ring regions of ANF to enable discrimination and measurement of intact endogenous ANF(99-126) and infused cleaved ANF (rat ANF(101-105/106-126)) in sheep plasma extracts. The assay which was validated by HPLC analysis of plasma extracts, had sufficient accuracy and precision to measure the metabolic clearance rate and half-life of cleaved ANF when infused in normal sheep.