Gastrin and somatostatin in plasma and gastric biopsy specimens in pernicious anemia

Methyl donor deficiency affects fetal programming of gastric ghrelin cell organization and function in the rat

Methyl donor deficiency (MDD) during pregnancy influences intrauterine development. Ghrelin is expressed in the stomach of fetuses and influences fetal growth, but MDD influence on gastric ghrelin is unknown. We examined the gastric ghrelin system in MDD-induced intrauterine growth retardation. By using specific markers and approaches (such as periodic acid-Schiff, bromodeoxyuridine, homocysteine, terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling, immunostaining, reverse transcription-polymerase chain reaction), we studied the gastric oxyntic mucosa cellular organization and ghrelin gene expression in the mucosa in 20-day-old fetuses and weanling pups, and plasma ghrelin concentration in weanling rat pups of dams either normally fed or deprived of choline, folate, vitamin B6, and vitamin B12 during gestation and suckling periods. MDD fetuses weighed less than controls; the weight deficit reached 57% at weaning (P < 0.001). Both at the end of gestation and at weaning, they presented with an aberrant gastric oxyntic mucosa formation with loss of cell polarity, anarchic cell migration, abnormal progenitor differentiation, apoptosis, and signs of surface layer erosion. Ghrelin cells were abnormally located in the pit region of oxyntic glands. At weaning, plasma ghrelin levels were decreased (-28%; P < 0.001) despite unchanged mRNA expression in the stomach. This decrease was associated with lower body weight. Taken together, these data indicate that one mechanism through which MDD influences fetal programming is the remodeling of gastric cellular organization, leading to dysfunction of the ghrelin system and dramatic effects on growth.

Gastric luminal somatostatin secretion of normals and patients with pernicious anemia and with Zollinger-Ellison syndrome

We studied the release of gastric luminal somatostatin-like immunoreactivity (SLI) in response to a pentagastrin infusion (0.9 microgram/kg/hr, intravenous) in five normal volunteers, five patients with pernicious anemia, and two patients with Zollinger-Ellison syndrome. In addition, we studied the gastric luminal SLI secretion in response to a gastric luminal acid perfusion in two patients with pernicious anemia. Our results have shown that: (1) pentagastrin caused a parallel increase in luminal hydrogen ions and SLI release in normal volunteers; (2) Zollinger-Ellison patients had elevated basal acid and SLI levels that did not increase further with pentagastrin; (3) pentagastrin did not increase gastric acid or luminal SLI secretion in pernicious anemia patients; and (4) in pernicious anemia patients, a gastric luminal acid perfusion caused a significant increase in gastric luminal SLI over baseline values. In conclusion, gastric luminal hydrochloric acid appears to be a factor which stimulates the secretion of luminal SLI in human beings.

Somatostatin, gastrin, and cholinergic muscarinic binding sites in rat gastric, duodenal, and jejunal mucosa

Clinical and experimental data indicate that the concentration of gastrin-I and somatostatin binding sites in human and rat gastric and duodenal mucosa may be changed in several pathologic conditions, including human peptic ulcer and cancer diseases. There are no data, however, indicating the distribution of receptor binding sites in the normal upper gastrointestinal tract. We studied the regional distribution of somatostatin-14, gastrin-I, and cholinergic muscarinic binding sites in membrane preparations from rat gastric corporeal and antral mucosa and in mucosa obtained from the duodenum and jejunum. The corporeal mucosa contained the most high-affinity gastrin binding sites (Bmax = 39.1 +/- 6.5 fmol/mg protein; Kd = 1.1 +/- 0.4 nM). The antral mucosa contained the most somatostatin and cholinergic muscarinic binding sites (Bmax = 65.7 +/- 6.6 fmol/mg protein and 460.3 +/- 101.8 fmol/mg protein, respectively). The duodenal and jejunal mucosal membranes contained somatostatin, gastrin, and cholinergic muscarinic binding sites in decreasing concentrations. Concentrations of binding sites are characteristic for particular gut regions and may help in analyzing their abnormalities.

Somatostatin release by human gastric mucosa. Studies in peptic ulcer disease and pernicious anemia

Somatostation has been postulated to have a paracrine modulating role in gastrin and gastric acid secretion. We applied the organ culture technique to examine somatostatin release by explants of human gastric mucosa taken from patients with active duodenal ulcer, from control subjects, and from patients with pernicious anemia. Somatostatin was found to be released at a constant rate by antral explants during 3 h of incubation. In active duodenal ulcer antral and fundic 2-h somatostatin release (18.7 +/- 2.6 pg/mg tissue (means + SE), n = 75; and 27 +/- 3 pg/mg tissue, n = 94, respectively) was significantly lower than release by control antral and fundic mucosa (83 +/- 17 pg/mg tissue, n = 39, and 72 +/- 16 pg/mg tissue, n = 42, respectively) (P less than 0.01). Somatostatin release by antral and fundic mucosa of patients with pernicious anemia was also significantly decreased (20 +/- 8 pg/mg tissue, n = 12, and 7.6 +/- 2 pg/mg tissue, n = 12, respectively) (P less than 0.05). These results imply possible impairments of the paracrine release of somatostatin in peptic ulcer disease and in pernicious anemia.