Abstract
The secretory responses to seven dopamine amino acid conjugated derivatives were compared with those to dopamine, using blood-perfused canine pancreas preparations. Each of these dopamine derivatives produced a dose dependent increase in the secretion of pancreatic juice. The rank order of the secretory responses and relative potency (dopamine =1) was: N-Ileu-dopamine (0.4)>N-Ala-Glu-dopamine (0.2)>N-γ-Glu-dopamine (0.1) = N-Gly-Pro-dopamine (0.1)>N-Gly-Gly-dopamine (0.01)>N-Gly-Gly-Leu-dopamine (0.005)=N-Gly-Gly-Pro-dopamine (0.005). The duration of action of doses of the derivatives which produced approximately equal secretory responses was about 1.2-2.7 times longer than that of dopamine. Dopamine and N-Ileu-dopamine which has the most potent secretagogue property among seven dopamine derivatives produced a secretin-like secretion of the pancreatic juice containing a high concentration of bicarbonate but had little effect on protein output with lower amylase activity.
