Using a specific radioimmunoassay (RIA) for α-rat atrial natriuretic polypeptide (α-rANP), we have demonstrated the presence of a considerable amount (6.10 ± 0.38 ng/g) (mean ± SE) of α-rANP-like immunoreactivity (α-rANP-LI) in the rat lung, the first organ through which atrial natriuretic polypeptide (ANP) released from the heart passes. High performance gel permeation chromatography coupled with the RIA revealed that most of α-rANP-LI eluted at the position of a low molecular weight form corresponding to synthetic α-rANP. In 2- or 5-day water-deprived rats, the concentration and content of α-rANP-LI in the lung decreased significantly compared with those of control rats. In addition, water-deprivation induced a significant decrease in the plasma concentration of α-rANP-LI simultaneously determined. There was a significant positive correlation between the concentrations of α-rANP-LI in the lung and plasma (r=0.591, P<0.01). These results indicate the presence of ANP in the lung and suggest physiological roles of ANP in pulmonary function.
|Biochemical and Biophysical Research Communications
|Published - 1986 3月 13
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