The Role of Food Intake on Gastric Mucosal Growth and Gastrin Receptors during Pregnancy and Lactation

Abstract

We examined the effects of pregnancy and lactation on mucosal growth and the numbers and affinity of gastrin receptors in the oxyntic gland mucosa in rats and compared these with changes in serum gastrin levels and food consumption. Gastric mucosal DNA, RNA, and protein contents were significantly increased during lactation. These changes were not observed in either pregnant or nonlactating rats which had given birth at the same time as the lactating animals. The gastrin-binding capacity of a membrane fraction of the oxyntic mucosa was also increased at the corresponding periods in lactating rats (Days 7,15,20). Scatchard plot analysis revealed that the number of gastrin receptors was significantly increased without any change in affinity. Food consumption and levels of serum gastrin remained unaltered in pregnant and nonlactating rats compared to virgin controls, but were significantly increased in lactating rats. Increased serum gastrin levels and gastrin binding capacities in lactating rats (Day 15) were abolished by preventing increased food consumption by means of pair feeding. The results demonstrate that the number of gastrin receptors in the oxyntic mucosa increases during lactation in rats. This increase is probably due to hypergastrinemia caused by increased food intake. The increased number of gastrin receptors may be involved in the mechanism of hypertrophic responses of the gastric mUCOSa in lactating rats. 0

Effects of CCK2 Receptor Blockade on Growth Parameters in Gastrointestinal Tract and Pancreas in Rats

“…In fact, the mucosal weight was reduced by almost 10% within 12 hr of treatment. The prompt reduction in oxyntic mucosal mass seen after CCK 2 receptor blockade was similar in magnitude and onset to that after food deprivation observed by Solomon (1986), Tabata & Johnson (1986) and Takeuchi & Johnson (1987). The rapid and fairly parallel reduction in both oxyntic mucosal weight (∂10% within 12 hr) and DNA content (∂20% in 2 days) is notable.…”

Hormonal Control of Rat Fetal Pancreas Development

“…Increased contents of pancreatic gastrin may not come from the mother, as pregnancy did not appreciably influence the levels of serum or antral gastrin when compared to nonpregnant control rats [34]. Our data certainly agree with an important role for gastrin in fetal rat pancreas development.…”

Casein Kinase II

“…Besides being involved in the control of acid secretion, the occupation of the CCK-2R was also associated with proliferation of the gastric mucosa, especially during lactation in rats (Takeuchi and Johnson 1987). Gastrin was also described as a growth factor for the small intestine and colon.…”