The effect of semistarvation on absorption by the rat small intestine in vitro and in vivo

Abstract

During a period of semistarvation there is a fall in the mass of body cells and a lowering of the basal metabolic rate (Wishart, 1934;Taylor & Keys, 1950;Grande, Anderson & Keys, 1958), the degree to which each change occurs depending upon the duration of the experiment and the severity of the dietary restriction. The loss of cellular mass and the fall in the metabolic rate depend upon the number of calories available, and provided that the caloric restriction is not too severe an equilibrium situation can be obtained. It was of interest therefore to investigate the absorptive ability of the small intestine during semistarvation, as it seemed a vulnerable organ in view of its great demands on the metabolic pool for the frequent replacement ofits epithelial lining (Leblond & Stevens, 1948;McMinn, 1954).We have found that after a period of semistarvation sufficient to cause a loss of about 20 % of the initial body weight, there is an enhanced rate of disappearance of both glucose and L-histidine from the small intestine of the rat in vivo, and that in vitro the small intestine from semistarved animals can transport both these substances against a concentration gradient to a greater extent than can the small intestine of rats fed on an 'ad libitum' diet. A preliminary report has been given by Neame & Wiseman (1959). METHODS Animal8 and diet. Male albino rats of an inbred strain were used, and were kept individually in separating cageswith free access to water. The food used throughout was Diet 86, purchased from The North-Eastern Agricultural Cooperative Society, Ltd., Bannermill Place, Aberdeen, its composition being: soluble carbohydrate 53.4%; protein, 20-0 %; fat, 3.8%; fibre, 3-3%; ash, 5-2%; moisture, 14-3%.All animals were inspected every day and the dietary regimen was as follows: Group A was fed ad libitum. Group B was fed 5 g food per rat per day for 5 days. Group C was fed 5 g food per rat per day for 9 days. Group D was fed 5 g food per rat per day for 9 days, and then fed ad libitum for 24 hr. Group E was fed 5 g food per rat per day for 9 days, and then fed ad libitum for 3 days. Group F was fed 5 g food per rat per day for 9 days, and then fed ad libitum for 7 days.

Effects of Semi-Starvation on the Total Body Composition and Absorptive Function of the Small Intestine of the Young Adult Female Rat

“…It is of interest, therefore, that the absorptive capacity of the small intestine of the rat and mouse is enhanced, rather than decreased, for. some nutrients such as D( + )-glucose after the imposition of a severe decrease in intake of a balanced food (Kershaw et al 1960;Hindmarsh et al 1967;Madge 1970) and the present work shows that this response is retained even when the animals have lost 40 % of body weight. Although there will always be difficulties in extrapolating data from one species to another, it seems valuable to pursue the influence of variable dietary deprivation at different ages and for different periods of time on digestive function in the rat because some principles may emerge which are applicable across species.…”

“…Experimental studies in the rat have shown enhanced absorptive capacity of the small intestine for some nutrients after dietary restriction had resulted in up to 23 % body weight loss (Kershaw et al 1960;Hindmarsh et al 1967). Jackson (1925) reported that young adult mammals, such as the rats used in the above experiments, are capable of losing about 50 % of their body weight before death.…”

“…The active transport of histidine has been shown to increase (Kershaw et al 1960;Hindmarsh et al 1967;Madge 1970). Lis et al (1972) showed for rats that after 10 days offood restriction to prevent growth but to maintain body weight there was increased L-methionine absorption from the small intestine, but the effect was no longer apparent after 51 days.…”

Influence of restricted diet on epithelial renewal and maturation in the mice jejunum.

“…It is expected that the small intestinal function is reflected partly by the mature cell number existing on the villi. Many investigators have observed the effect of diet on the cell renewal or the digestive and absorptive functions (1)(2)(3)(4). However there has been little research to examine the relationship between cell renewal and the functions.…”

Influence de la composition du régime alimentaire sur le transit digestif et l'absorption intestinale des acides aminés chez le poulet

“…Chez les mammifères, l'influence du régime alimentaire sur la vitesse d'absorption des acides aminés fait l'objet de nombreux travaux depuis que Neame et Wiseman (1959) puis Kershaw, Neame et Wiseman (1960) ont montré que la restriction éner-gétique entraîne chez le rat une augmentation du transport actif de l'histidine.…”