Decreased plasma epinephrine concentrations after glucose ingestion in humans

Plasma levels of norepinephrine (NE), epinephrine (E), immunoreactive insulin (IRI), and glucose were measured in six healthy volunteers after glucose consumption and in six volunteers after a water solution. Ingestion of the glucose (100 g) solution significantly decreased E levels from 46.7 ± 8.0 to 20.8 ± 1.9 pg/mL ( P < 0.01). Three hours after the glucose ingestion, plasma E levels nearly returned to basal values. Plasma IRI and glucose levels peaked at 45 minutes after glucose consumption ( P < 0.01), then declined toward basal values. Plasma NE levels were unaffected by glucose consumption. There were no changes in glucose, IRI, NE, or E levels in the control group. These results suggest that E behaves as a counter-regulatory hormone to insulin under stimulation by glucose.