Atrial natriuretic factor in the spinal cord of normotensive and hypertensive rats.

Atrial natriuretic factor (ANF) was investigated in the rat spinal cord and hypothalamus using two radioimmunoassays. ANF was also quantified in both tissues of Spontaneously Hypertensive Rats and Dahl rats. Spinal cord and hypothalamus were found to be immunoreactive to proANF and its near-NH2- or near-COOH-terminal fragments. A major part of the extracted ANF was a COOH-terminal peptide smaller than or the same as ANF (Ser99-Tyr 126). SHR had higher hypothalamic and spinal cord ANF concentrations than Wistar Kyoto rats, while the Dahl salt-sensitive animals exhibited an increase in spinal cord ANF when compared with the Dahl salt-resistant group. The data suggest that spinal cord may produce ANF locally with processing similar to that in hypothalamus. Changes in ANF concentrations occurring during the course of hypertension remain to be further investigated.