Increased sensitivity of gastrin release to adrenaline in duodenal ulcer

The role of catecholamines in clinical medicine

The sympathetic nervous system is of major importance for the regulation of several physiological functions. Drugs which inhibit the actions of catecholamines and adrenergic drugs are used in the treatment of many clinical disorders. The potential role of catecholamines in a number of human diseases has, however, until recent years been studied to a limited extent only due to lack of methods for quantitation of sympathetic nervous activity. After the development of enzymatic isotope-derivative assays, reliable measurements of noradrenaline and adrenaline in plasma became available. Studies in man have shown that plasma noradrenaline is an index of sympathetic nervous activity. The present survey deals with sympathetic nervous activity and plasma adrenaline in a number of clinical disorders viz. arterial hypertension, duodenal ulcer, thyrotoxicosis, diabetes mellitus and ketotic hypoglycemia.

The gastroenteroinsular response to glucose ingestion during postexercise recovery

This study examined gastrointestinal hormone and peptide responses when glucose was ingested after prolonged exercise. Six endurance-trained male athletes ran on a treadmill for 2 h at 60% VO2 max. Immediately after the run, the athletes consumed 75 g of glucose in 250 ml of water (ExGLU) or flavored water as a placebo control (ExPL). On a separate visit, the athletes rested for 2 h and then consumed glucose (ConGLU). During the first 60 min of recovery from exercise alone (ExPL), plasma vasoactive intestinal peptide (VIP), gastrin, and glucagon-like peptide-1 (GLP-1) all increased significantly, whereas glucose, insulin, and gastric inhibitory polypeptide (GIP) were unchanged from the immediate postexercise value. When glucose was ingested after exercise (ExGLU), glucose, insulin, VIP, gastrin, GLP-1, and GIP were all increased (P < 0.01). However, when glucose was ingested after resting for 2 h (ConGLU), VIP levels were unaffected, although glucose, insulin, gastrin, GLP-1, and GIP levels increased (P < 0.05). The plasma glucose response was greater (P < 0.03) and the plasma insulin response lower (P < 0.004) during ExGLU compared with ConGLU. There was a significantly higher (P < 0.01) VIP response during the initial period of recovery in ExGLU than there was with both ExPL and ConGLU. Plasma VIP showed a modest negative correlation with circulating glucose (r = -0.35, P < 0.03) and insulin (r = -0.37, P < 0.03) during the ExGLU recovery period. In summary, when glucose is ingested after prolonged exercise, there is mild insulin resistance and a corresponding rapid transitory increase in plasma VIP. These data suggest that VIP may play an important glucoregulatory role when glucose is ingested during the immediate postexercise recovery period.

Sympathoadrenal activity and psychosocial stress. The significance of aging, long-term smoking, and stress models

Recent studies have indicated that the increase in plasma norepinephrine and sympathetic activity with aging in healthy subjects is largely due to long-term cigarette smoking. In patients who have or have had duodenal ulcer the increase in plasma norepinephrine with age was markedly increased. These patients as a group perceive their lives somewhat more stressful than the general population and they tend to die prematurely due to smoking-associated diseases. These patients may select dysfunctional coping strategies like smoking, which may result in organ pathologies and a compensatory increase in plasma norepinephrine. No close correlation has been established between plasma epinephrine and "ill health." High plasma epinephrine levels may have a deleterious effect on the cardiovascular system in elderly subjects during certain conditions. In a population study, we found, however, that low resting plasma epinephrine levels were associated with an unfavorable survival rate. We speculate that an inadequate response to psychosocial stress and the choice of dysfunctional coping strategies may be more harmful and cause more "ill health" than hypersecretion of stress hormones like epinephrine and cortisol, which has been the traditional view. We suggest that there are different stress states. Stress hormones like epinephrine and cortisol may play a major role during situations like combat, illness, and strenuous exercise. In response to psychosocial stress, dysfunctional coping strategies are, however, largely responsible for harmful effects of stress.

Acute effects of smoking during modified sham feeding in duodenal ulcer patients. An analysis of nicotine, acid secretion, gastrin, catecholamines, epidermal growth factor, prostaglandin E2, and bile acids

Smoking is associated with an increased incidence of duodenal ulcer with a high relapse rate, and smokers tend to be slow healers. The etiology responsible for this remains unknown, and there is general disagreement as to whether smoking affects gastric secretion. The aim of the present study was to investigate both aggressive and protective factors in response to vagal stimulation induced by modified sham feeding (MSF) in duodenal ulcer patients when smoking versus not smoking. On smoking days, nicotine concentrations in plasma averaged about 15 ng/ml and were extremely high in saliva and gastric juice (> 1300 and > 800 ng/ml, respectively). MSF induced a significant decrease in intragastric pH during non-smoking (p = 0.01) but not during smoking. Acid output 1 h after MSF was lower on smoking than on non-smoking days (p = 0.02), as was volume secretion (p = 0.02). Plasma gastrin concentrations were significantly increased during MSF on non-smoking days (p = 0.04) but not on smoking days, the concentrations during the whole day being lower on smoking days (p = 0.002). Plasma catecholamine levels were unaffected by MSF, whether smoking or not. However, plasma concentrations of noradrenaline decreased during the smoking of a single cigarette (p = 0.03), whereas those of adrenaline were increased on smoking days (p = 0.02). Epidermal growth factor concentrations were decreased in gastric juice after MSF during non-smoking (p = 0.01) but not during smoking. Although prostaglandin E2 (PGE2) concentrations in gastric juice were unaffected by MSF, PGE2 output increased after MSF whether smoking or not, the increment being non-significantly less during smoking (p = 0.09).(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of sympathomimetics on gastrin secretion from antral G cells in culture

Clinical data indicate that the control of gastrin secretion from the human antrum has a beta-adrenergic component. The purpose of the present study was to investigate whether this was due to the presence of beta-adrenergic receptors on the G cells. A newly developed short-term culture system of enriched antral G cells was used to eliminate the possibility of input from factors in the circulation and the peripheral innervation. The results demonstrated that epinephrine and terbutaline (a beta 2 agonist) significantly stimulated gastrin release above basal which could be blocked by the addition of propranolol (beta-adrenergic antagonist). However, the beta 1 agonist, dobutamine, and phenylepinephrine did not stimulate gastrin release above basal. In addition, simultaneous administration of epinephrine and the neuropeptide, bombesin, resulted in a potentiation of gastrin release. It was concluded that the stimulatory effect of the sympathetic system on gastrin release was mediated through beta 2-adrenergic receptors. The data indicated that adrenaline released from the adrenal medulla and gastrin releasing peptide (the mammalian homolog of bombesin) released from the intrinsic innervation of the stomach interact with respect to the stimulation of gastrin.

Plasma neurotransmitters and cortisol in duodenal ulcer patients. Role of stress

Levels of noradrenaline, adrenaline, dopamine, free serotonin, platelet serotonin, and cortisol were measured in the plasma of duodenal ulcer patients and controls. All subjects received antacids, and these substances were also measured. During relapse, all patients showed raised noradrenaline, adrenaline, dopamine, free serotonin, and cortisol values. In contrast, platelet serotonin showed very low values, which correlated negatively with all the former, except free serotonin. No correlations were found in parameters of the controls. After healing, significant reductions of noradrenaline, adrenaline, dopamine, free serotonin, and cortisol and significant increases of platelet serotonin values were observed. However, only dopamine, free serotonin, and cortisol reached normal values. Noradrenaline and adrenaline remained higher and platelet serotonin lower, both significantly more so than normals. These still-altered parameters showed similar correlations to those found during relapses. The present results demonstrate that some baseline autonomic system imbalance exists in patients, amplified and accentuated during relapse. We discuss the possibility that stress plays some role in triggering duodenal ulcer relapse.

Adrenaline stimulates acid production in isolated pig and human parietal cells

To investigate the mechanisms of adrenergic stimulation of the parietal cell and to study the possible relationship between the stress hormone adrenaline and duodenal ulcer, the effects of adrenaline and various adrenoceptor agonists and antagonists were investigated in parietal cells isolated from pig stomachs and from endoscopic biopsy specimens taken from the gastric mucosa of patients. Parietal cell acid production was assayed by the aminopyrine accumulation technique. Adrenaline as the sole drug showed poor or no stimulatory effect but potentiated histamine-stimulated acid production. In the presence of histamine, beta-adrenoceptor agonists caused a stimulation of acid formation with the potency order isoproterenol greater than adrenaline greater than noradrenaline. The beta-2-selective antagonist ICI118551 was a more potent inhibitor of acid production than both the beta-1 antagonist practolol and the H2-receptor antagonist cimetidine. Studies of (3H)-dihydroalprenolol (DHA) binding to purified parietal cell membranes showed a protein-concentration-dependent and specific binding of 2.2 +/- 0.6 pmol DHA/microgram. Adrenaline increased gastric acid production in both pig and human parietal cells, most likely through a beta-2 receptor on the parietal cell. The adrenaline stimulatory effect in cells obtained from patients with peptic ulcer was more pronounced than in cells from non-ulcer patients, which indicates a possible role of adrenaline in some types of ulcer disease.

Gastrin responses in patients with adrenergic insufficiency

High basal gastrin levels in pure autonomic failure could result from peripheral vagus nerve involvement, whereas the increased response during hypoglycaemia may reflect adrenergic supersensitivity. A reduced gastrin increment in multiple system atrophy was found following insulin-hypoglycaemia and is consistent with decreased gastrin release secondary to diminished central sympathetic nervous system activation in the absence of peripheral denervation supersensitivity.

hPP and gastrin response to a liquid meal and oral glucose during prolonged severe exercise, caloric deficit, and sleep deprivation

Sixteen young healthy military cadets were subjected to prolonged severe exercise, caloric supply deficiency, and sleep deprivation during a 5-day ranger training course. Several cadets complained of gastric discomfort. The fasting and postprandial human pancreatic polypeptide (hPP) and gastrin levels induced by a liquid meal (no. = 9) and peroral glucose load (no. = 7) were measured during normal school activities (control) and on the third day during the course. The results showed that the fasting level of hhPP was significantly increased during the course. Both during meal and glucose stimulation the hPP level during the course was significantly higher at most registrations than during control conditions. The fasting level of gastrin was not changed. The maximal level of gastrin during meal stimulation was higher during the course than during the control period. Glucose loading, on the other hand, did not change the gastrin response. The integrated response of hPP and gastrin were not changed during the course either for the liquid meal or for the peroral glucose load.

The mechanism of gastrin release in cysteamine-induced duodenal ulcer

Duodenal ulcer can be induced in rats by a single dose of cysteamine. The ulcer formation is accompanied by acid hypersecretion and elevated serum gastrin levels. This study was performed to elucidate the mechanisms of gastrin release after an ulcerogenic dose of cysteamine. Cysteamine induced a rise in serum gastrin from 29 +/- 5 pg/ml to a maximum of 203 +/- 62 pg/ml after 3 h in unoperated rats, whereas no rise was seen in vagotomized or antrectomized rats. The beta-adrenergic blocking agent propranolol strongly inhibited cysteamine-induced gastrin release, whereas atropine dependent on an intact vagus and may be mediated by beta-adrenergic receptors.

Adrenergic mechanisms in selected diseases: arterial hypertension, duodenal ulcer, primary depressive illness, malignant tumors, and ketotic hypoglycemia

The sympathetic nervous system is of major importance for the regulation of several physiologic functions. Drugs that inhibit the actions of catecholamines and adrenergic drugs are used in the treatment of many clinical disorders. The potential role of catecholamines in a number of human diseases has, however, until recent years been studied to a limited extent only due to lack of methods for quantitation of sympathetic nervous activity. After the development of enzymatic isotope-derivative assays, reliable measurements of noradrenaline and adrenaline became available. Studies in man have shown that plasma noradrenaline is an index of sympathetic nervous activity. The present survey deals with noradrenaline and adrenaline concentrations in blood, tissue, and cerebrospinal fluid in a number of clinical disorders viz. arterial hypertension, duodenal ulcer, malignant tumors, primary depressive illness, and ketotic hypoglycemia.

Effect of four dopamine receptor antagonists on gastrin secretion in healthy subjects

The effect of 1 week of oral treatment with four antidopaminergic drugs--metoclopramide, sulpiride, haloperidol, and pimozide--on fasting and meal-stimulated serum gastrin levels has been evaluated in healthy subjects. All of the four drugs significantly reduced the gastrin response to a meal, whereas basal concentration was unaffected. It is suggested that this action is mediated by central nervous system dopamine receptor blockade, which might act either via nervous or humoral mechanisms to inhibit gastrin release.

Inhibition of gastrin secretion by hypertonic solutions in patients with pernicious anaemia and duodenal ulcer

Serum gastrin increased in patients with pernicious anaemia after a beef-meal, but decreased after an oral load of glucose, xylose or sodium chloride. 50 g of glucose and 25 or 75 g of xylose suppressed serum gastrin to approximately 40% of basal values at 60 min and were slightly more effective than 10 g of sodium chloride. There was no rise in beef-meal stimulated serum gastrin concentration in vagotomized patients and only a slight rise in two patients with duodenal ulcer when an oral dose of 10 g of sodium chloride was given together with the beef-meal. 25 g of xylose suppressed basal serum gastrin concentration significantly in six vagotomized patients. Nasal administration of small amounts of vasopressin decreased basal serum gastrin significantly in six vagotomized patients. Nasal administration of small amounts of vasopressin decreased basal serum gastrin significantly in all subjects examined. Further studies indicated, however, that vasopressin was only effective when pharmacological plasma concenten orally and intraduodenally were compared in six patients with pernicious anaemia. Serum gastrin concentration decreased approximately to the same extent in both experiments. It is concluded that the inhibitory effect of glucose on gastrin secretion most likely is mediated hormonally via osmo-receptors located in the small intestine.

Increased plasma noradrenaline and serum gastrin in patients with duodenal ulcer

Serum gastrin, serum insulin, plasma noradrenaline, plasma adrenaline, pulse rate and blood pressure were measured repeatedly during 24h in six patients with duodenal ulcer and in six control subjects. Mean serum gastrin concentration was 3-4 times higher in duodenal ulcer patients than in controls during both the day and at night. Serum insulin was the same in both groups of subjects. Overnight fasting and mean supine plasma noradrenaline as well as mean supine pulse rate were significantly higher in duodenal ulcer patients than in controls. Plasma adrenaline and arterial blood pressure were the same in patients and controls. These results suggest that sympathetic nervous activity is increased in patients with duodenal ulcer. The increased sympathetic nervous activity may mean that duodenal ulcer patients are subject to more stress than normal subjects or may be compensatory to increased vagal nervous activity presumed by some authors to be present in such patients.