Gastric H+ secretion in presence of substrates: absolute dependence on secretagogues

Spontaneously secreting gastric mucosae of the bullfrog (Rana catesbeiana) were brought to resting states in the absence of both the exogenous secretagogue and energy-yielding substrate, either by treatment with burimamide or by the classical method of prolonged preincubation. Glucose, pyruvate, lactate, and tricarboxylic acid cycle intermediates were compared with short- and long-chain fatty acids as potential substrates on these resting mucosae to determine if the latter could initiate and sustain H+ secretion in the absence of added secretagogues. The experimental data indicate that fatty acids cannot stimulate acid secretion from the resting state by preempting the requirement for secretagogues. Although fatty acids may serve as preferred substrates in comparison with glucose, glycolytic intermediates, and tricarboxylic acid cycle intermediates, acid secretion is obligatorily dependent on the presence of endogenous or added secretagogues. The implications of this finding with respect to one of the recently proposed hypothesis for secretagogue regulation of gastric hydrochloric acid secretion are discussed.