Simultaneous Measurements of Cholecystokinin-Induced Changes in Absorption Spectrum of Cytochromes, Nad(p)h-Fluorescence, and Enzyme Output in Isolated Pereused Rat Pancreas

Redox states of cytochromes and nicotinamide nucleotides were recorded simultaneously and continuously in the isolated perfused rat pancreas with the aid of a scanning organ spectrophotometer and a fluorometer. Continuous stimulation with 2 mU/ml CCK induced immediate reduction of cytochromes, a(a3), b, and c+c1; almost no change in NAD(P)H-fluorescence; and a gradual increase in secretory response (pancreatic protein output). The time lapse between the reduction of cytochromes and the initiation of secretory response was about 6 min. Continuous stimulation with 50 mU/ml CCK induced immediate marked reduction of cytochromes; a small increase in NAD(P)H-fluorescence; and a large rapid increase in secretory response followed by a gradual return to the resting level. Anoxic treatment of the preparation always caused parallel reduction of the cytochromes and nicotinamide nucleotides without inducing the secretory response.