Gastrin-stimulated Gastric Acid Secretion Research Articles

Characteristics and tachyphylaxis of gastrin-stimulated gastric acid secretion in the cat.

1. The characteristics of gastrin-stimulated gastric acid secretion were investigated in conscious cats fitted with chronic cannulated gastric fistulae, with particular reference to tachyphylaxis. 2. There is a significant postive correlation between the peak acid secretion in response to pentagastrin 8 microgram kg-1 hr-1 and body weight. Male cats secret significantly greater amounts of acid in response to pentagastrin than females. The difference is lessened, but not eliminated, by expressing the acid out put in terms of body weight. 3. Pentagastrin stimulates a dose-dependent increase in acid secretion in the range 0.5-32 microgram kg-1 hr-1 when the response to each dose is assayed on separate occasions. Pentagastrin 64 microgram kg-1 hr-1 does not produce a further increase in acid secretion. The acid response to pentagastrin 1-16 microgram kg-1 hr-1 assayed on a single occasion by a continuous infusion method shows a dose-response relationship up to 8 microgram kg-1 hr-1 when it reaches a plateau of secretion. There is no difference between the two methods of assaying the gastric acid stimulating activity using doses of pentagastrin up to 8 microgram kg-1 hr-1. 4 The acid secretion in response to pentagastrin 8 microgram kg-1 hr-1 reaches a maximum after 45 min of stimulation and thereafter shows tachyphylaxis. Over a period of 5 hr there are at least two phases of tachyphylaxis distinguishable. During the period 0.75--2.5 hr of stimulation there is a fast phase of tachyphylaxis (-32.0 muequivH+kg-1 15 min-1). This is followed by a slow phase of tachyphylaxis (-9.4 muequivH+kg-1 15 min-1) up to 5 hr of stimulation. 5. The absolute rate of the fast phase of tachyphylaxis of acid secretion (muequivH+kg-1 15 min-1) increases with increasing doses of pentagastrin, but rates of tachyphylaxis are similar when expressed as a percentage of the peak acid response to the particular dose of pentagastrin (5.1--7.8% 15 min-1). Synthetic human gastrin-17, the synthetic C-terminal decapeptide of human gastrin and the C-terminal tetrapeptide of gastrin have comparable rates of tachyphylaxis. The possible receptor models for the tachyphylaxis of gastrin-stimulated acid secretion are discussed.

Canine pancreatic responses to intestinally perfused fat and products of fat digestion.

Canine pancreatic responses to intestinally perfused fat and products of fat digestion.

Effect of Gastrin and SC 15396 on Gastric Motility in Dogs

A continuous infusion of porcine gastrin preparations, including crude gastrin, gastrin I, or gastrin II, in doses submaximal for gastric acid secretion, stimulated rhythmic antral contractions in the intact stomach or innervated antral pouch of dogs. SC 15396 markedly decreased gastrin-stimulated gastric acid secretion, but had no effect on gastrin-stimulated antral motility. Provided that the endogenous release of gastrin can be shown to produce an effect similar to exogenous gastrin, stimulation of rhythmic antral contractions should be included as one of the physiological actions of gastrin.

The primate as an experimental animal suitable for measuring gastrin-stimulated gastric acid secretion.

A study of the alteration of secretory patterns through the use of Heidenhain pouches in twoMacaca nemestrina, following subcutaneous injection of a gastrin preparation, revealed that the response was more reliable when the dorsal trunk, rather than the anterior thigh, was utilized as the site of injection. A plateau of maximal secretory response was obtained when 18–25 mg. of the extract per kilogram of body weight was injected. Although the observations were not conclusive, they suggested that pepsin is liberated by a “washing-out” process but is also continuously secreted in response to continued stimulation with gastrin extract. Evaluation of the monkey's response to stimulation by gastrin extracts established that theMacaca nemestrina is a different type of experimental animal when compared to the dog. The dog shows a response of gastric secretion to much smaller amounts of the gastrin extract and is less sensitive to other stimuli of an external nature.

THE EFFECT OF VAGOTOMY ON GASTRIN-STIMULATED GASTRIC-ACID SECRETION IN MAN

THE EFFECT OF VAGOTOMY ON GASTRIN-STIMULATED GASTRIC-ACID SECRETION IN MAN