THE EFFECT OF ANGIOTENSIN ON RAT INTESTINAL FLUID TRANSFER

Abstract

SUMMARY Fluid transfer by isolated everted sacs of rat jejunum, ileum and intact colon prepared from adrenalectomized-nephrectomized rats 48 h after operation was reduced when compared with that of sacs prepared from untreated controls (P < 0·001). Angiotensin at 10−10 g/ml significantly (P < 0·01) stimulated fluid transfer by intestinal sacs prepared from the adrenalectomized-nephrectomized rats; all three regions of gut were equally sensitive. Fluid transfer was similarly reduced in stripped colon sacs prepared from adrenalectomized-nephrectomized rats. Angiotensin had a dose-dependent biphasic action on fluid transfer by stripped colon sacs: low concentrations (10−11 and 10−12 g/ml) stimulated (P < 0·05), whilst high concentrations (10−9 and 10−8 g/ml) inhibited fluid transfer (P < 0·01). Histological examination of the colon preparations showed that the stripping procedure removed the ganglia, indicating that both angiotensin effects were due to direct action on the colon mucosa. The significance of these results is discussed in relation to the role of angiotensin in the control of salt and fluid transport by the mammalian kidney and other epithelial tissues.