Atrial natriuretic polypeptides elevate the level of cyclic GMP in the rat choroid plexus.

We studied the effect of synthetic rat alpha-atrial natriuretic polypeptide (1-28) (ANF-(99-126)) and related atrial natriuretic polypeptides on the accumulation of cyclic GMP (cGMP) in isolated rat choroid plexus in vitro, the objective being to determine whether ANF-(99-126) binding sites are physiologically active receptors. One microM of ANF-(99-126) increased the level of cGMP within 30 s and the accumulation reached the maximum level 5 min after adding of ANF-(99-126) to the incubation media. Significant increase in the level of cGMP depended on concentrations of the ANF-(99-126), ANF-(101-126) and ANF-(103-125), with a range of 10.0 nM to 10.0 microM. These data indicate that binding sites for ANF-(99-126) in the rat choroid plexus may be physiologically active receptors, possibly linked to the production of cerebrospinal fluid.