Effects of atrial natriuretic factor on renal function in chronic hypoxic rats

The renal effects of atrial natriuretic factor (ANF) were studied in chronic hypoxic (HA) and sea level (SL) rats. It was found that after 4 weeks of exposure to simulated 18,000 ft hypoxia, all HA rats were in apparently good health, and base line renal function was not significantly different from SL rats. Both doses (0.1 and 0.3 microgram/minutes/kg) of ANF administered produced a marked increase in urinary flow, sodium and potassium excretion in the SL rats. In the HA rats, the increase in water and salt excretion were comparatively mild, and the only statistically significant response was to the higher dose of ANF. ANF did not cause significant changes in the glomerular filtration rate in either group of rats. It is concluded that these animals showed an impaired response to ANF after exposure to chronic hypoxia.