Studies of secretin-stimulated insulin responses in man

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Abstract

Recent studies have suggested that secretin, like glucose, stimulates a rapid insulin response from a small storage pool. In order to evaluate the mechanism of the secretin-stimulated insulin response, small (15 U) rapidly administered intravenous injections (pulses) of secretin were given before, during, and after a 20 hr 300 mg/min glucose infusion. Contrary to previous studies demonstrating that the acute insulin response to a small (5 g) pulse of glucose given 45 min after the start of the glucose infusion was significantly diminished compared to the response to the preinfusion pulse, the acute insulin response (2-5 min Δimmuno-reactive insulin μU/ml) to 15-U secretin pulses exhibited a greater than twofold increase (before: 31.1±15.4; during: 71.2±40.4, μU/ml, mean ±SD, P < 0.02). The increased response to secretin was also found after 20 hr of continuous glucose infusion, but was not observed 1 hr after cessation of the infusion when plasma glucose levels returned to control values. Thus, this increased response to secretin was glucose dependent.

Authors

Roger L. Lerner, Daniel Porte Jr.