Parsons Bj

Effects of angiotensin II on fluid transport, transmural potential difference and blood flow by rat jejunum in vivo.

A method has been described for the measurement of fluid transport by rat jejunum in vivo over two consecutive 30 min periods. 2. Subpressor infusion rates of angiotensin (0‐59 ng/kg per minute) stimulate fluid transport, while high (pressor) infusion rates (590 ng/kg per minute) inhibit fluid absorption. 3. Both the inhibitory and stimulatory effects of angiotensin on fluid transport are not accompanied by any change in the transmural p.d., total blood flow to the jejunum or distribution of blood flow within the wall of the jejunum. 4. These results are discussed in relation to the mechanism of action of angiotensin on fluid transport and its role in sodium and water homoeostasis.

The effect of angiotensin on cation transport by rat kidney cortex slices.

1. A study has been made of the effect of angiotensin (10−12 g/ml.) on active and passive transport of sodium, potassium and water between rat kidney cortex slices and the incubation medium.

Noradrenaline as a possible mediator of the actions of angiotensin on fluid transport by rat rejunum in vivo

1. Net fluid absorption and transmural potential difference were measured in the rat jejunum in vivo.

Studies on the mechanism of action of angiotensin on ion transport by kidney cortex slices

1. A study has been made of the effects of cyclic AMP, phosphodiesterase inhibitors and protein synthesis inhibitors on the response of rat kidney cortex slices to physiological doses of angiotensin.

Intestinal fluid absorption in spontaneously hypertensive rats.

A comparison has been made of intestinal fluid absorption between male Okamoto spontaneously hypertensive rats (s.h.r.) and normotensive male Wistar controls. S.h.r. show enhanced fluid absorption both in hypertensive adults and in young s.h.r. before hypertension has developed. Several potential causes for increased fluid transport in s.h.r. were tested using pharmacological antagonists. It is unlikely that enhanced fluid absorption is due to high sympathetic nervous activity, the renin‐angiotensin system or is secondary to hypertension. Intestine from s.h.r. have a high short‐circuit current indicating a change in ion pump activity. These results are discussed in relation to the possible causes of increased fluid (ion) transport by the intestine of s.h.r.