Ricinoleic acid causes secretion in autotransplanted (extrinsically denervated) canine jejunum

To examine the role of extrinsic nerves and hormones in intestinal secretion of fluid, we studied the effect of ricinoleic acid on absorption by isolated, autotransplanted jejunal loops in four dogs. Compared to perfusion with control solution, the addition of ricinoleic acid caused reversible secretion of water and electrolytes and inhibition of glucose absorption, as previously described in the innervated intestine. In contrast, oral castor oil caused diarrhea but had no effect on absorption from the denervated loop. Thus, the secretory action of ricinoleic acid is maintained without the influence of extrinsic nerves; in addition, further support is added to the proposal that hormones do not mediate secretion in this model. These findings support a local mechanism for the secretion induced by ricinoleic acid.