Exocrine Pancreas and Experimental Dietary Lesions

Influence of starving on the rat gastric mucosa -- light and electron microscopical findings

The histology and ultrastructure of the rat gastric mucosa were investigated during 168 hours of starvation. An increased desquamation of individual foveolar cells was found. In the preserved cells of the foveolae, the content of the PAS positive mucosubstances did not change during starvation, and no changes took place in the appearance and in the amount of the mucous granules at the electron microscopic investigation. The number of lipid droplets increased in the mucous foveolar cells within 24 and 48 hours. During starvation the mitochondria (mainly in the parietal cells) were enlarged and contained rare mitochondrial cristae. Some mitochondria were distintegrated and removed by lysosomes. The number of lysosomes (mainly cytosergresomes) was markedly increased n parietal cells. A collapse of the intracellular canaliculi occurred as well as a narrowing in the tubulovesicular profiles. In chief cells the profiles of the granular endoplasmic reticulum and Golgi apparatus were reduced. It was shown that the ultrastructural changes induced by starvation can be interpreted functionally in changed histochemical parameters of the gastric mucosa.

Histochemical findings in the rat gastric mucosa during starvation

The influence of starving on the activity of enzymes of the rat gastric mucosa was investigated by selected histochemical methods. Beside the conventional methods of enzymatic histochemistry the technique of semipermeable membranes was used in the proof of lysosomal enzymes. Dehydrogenases were proved in aqueous and also in gel media with PMS. During the starvation in the parietal cells a marked increase took place in the activity of acid phosphatase, E-600 resistant esterase, less in beta-glucuronidase. High activity of the lysosomal enzymes in macrophages did not change during starvation. Nor did any changes took place in the activity of alkaline phosphatase in the endothelium of the capillaries. The chief cells in the control and starving animals, in contrast to the human gastric mucosa, did not contain any non-specific esterase. Concerning dehydrogenases, parietal cells with a different activity of these enzymes were observed both in starved and control animals. In the rat gastric mucosa starving induced changes in the activity of the enzymes which mark important organelles of the cells. Thus it is possible to consider the observed histochemical changes as a functional manifestation of morphological damage of cellular structures which are affected during starvation.

Histoenzymatic and ultrastructural findings in the human gastric mucosa during fasting

In this study the influence of fasting on the structures in the human gastric mucosa was followed using selective histoenzymological and electronmicroscopic method. The gastrobioptical material of 7 healthy volunteers was examined after 24 to 240 hour fasting. During fasting an increased acid phosphatase activity in the chief cells of the human fundal mucosa was observed. The activity of the nonspecific esterase (naphtyl esterase) in the chief cells decreased mainly after 240 hour fasting. In the electronmicroscopic examination of the chief cells during fasting a multiplication of lysosomes and narrowing of the granular endoplasmic reticulum was observed. In some chief cells during fasting an agglomeration of zymogen granules was seen while in others only a few granules were observed. In the parietal and other cells of the human gastric glands a steatosis, which attained excessive values, was seen after 72 and 240 hours of fasting. We believe that this steatosis occurred mainly on the strength fasting lipemia with the possible participation of other factors. The changes in the mitochondrial structure of the parietal and other cells of the human gastric mucosa were only slightly pronounced. "The decreased" activity of dehydrogenase in the steatotic parietal cells under a histochemical examination may represent only findings caused by the agglomeration of a large amount of lipid drops in the steatotic cells. After 72 and 240 hours of fasting the parietal cells contained collapsed, underdeveloped intracellular canaliculi and narrowed tubulovesicular profiles probably related to the decreased HCl production. Generally it can be said that the observed morphological changes are the consequences of the decreased function of human gastric mucosa cells during fasting and that these regressive changes are reversible and they are caused by an insufficiency of nutrition.