effect of methotrexate [MTX] on the small intestine of the mouse: V-cytochemical study

Cytochemical analysis of the normal mouse intestine reveals the presence of a high concentration of proteins, RNA and DNA, carbohydrates and lipids. The Golgi apparatus zone gives a PAS-positive reaction confirming its role in the secretion of mucopolysaccharides, particularly in goblet cells and cell membranes. The brush border is strongly PAS-positve. The crypt lumen contains diffuse acid mucopolysaccharides and glycogen granules. After MTX-treatment, all cytochemical reactions show a decrease in the amount of metabolites studied [total proteins, nucleic acids, carbohydrates, fats]. Of all these substances, proteins show the most detectable decrease in amount than control. The decrease is more pronounced in crypts than in villi. We conclude that MTX produces an imbalance in the absorptive power of cells and/or in the coordinate synthesis of DNA, RNA and protein resulting in a suppression in their synthesis. The amount of these substances shows variability [decrease then increase] depending on the physiological state of the cells. After recovery, the DNA content increased and consequently RNA and proteins also increased and reached the control levels

Histamine content of the digestive tract of a catfish Clarias batrachus (Linn.) in relation to spawning, sex and seasonal variation.

Histamine content of the digestive tract of a catfish Clarias batrachus has been estimated biologically on the atropinized guineapig ileum. A significant decrease of histamine content has been observed with the decrease of gonosomatic index (G.S.I.) during breeding season in female fishes, while no such type of change in histamine content of male fishes during breeding season has been noted. In the summer histamine content of both the sexes was signivicantly lowered in comparison with the histamine content during breeding season in both the sexes. It is concluded that higher histamine content in prespawing female fishes during breeding season may be due to the inhibition of the enzyme histaminase by gonadotrophines. It is also suggested that the route of inactivation of histamine during breeding season may be different in both the sexes, while in summer a common factor may be involved in depletion of histamine content of both the sexes.