[Amino acid production in the isolated and perfused rumen wall of sheep].

The metabolism of amino acids and urea in an isolated perfused wall of sheep rumen was studied by the method of organ perfusion, using 3 kinds of perfusate. In experiments with semisynthetic perfusate containing urea (SPurea) the levels of lysine, valine, glutamic acid and alanine increased at a simultaneous decrease of levels of leucine, arginine, aspartic acid, threonine and methionine. In perfusions with the semisynthetic medium without urea (SP) the levels of lysine, valine, phenylalanine, isoleucine, glutamic acid, glycine and alanine increased, the level of threonine dropped.

[Renal excretion of urea and electrolytes in sheep after extracellular fluid expansion with an isotonic solution of sodium chloride].

Sheep of the Merino breed, given 10.11 g nitrogen daily (after Czechoslovak Standard CSN 46 7007) were studied for the effect of the expansion of the extracellular fluid (ECF) by an infusion of an isotonic solution of NaCl (at a rate of 5% of live weight), as exerted on the renal excretion of urea and on the sodium and potassium electrolytes. The high natriuresis, induced by the expansion of ECF, resulted in a statistically significant increase in the clearance of urea, free water, and solutions, and in higher diuresis.

[The effect of the antidiuretic hormone on the renal excretion of urea and electrolytes in fed and fasting sheep].

The effects of the antidiuretic hormone (ADH) on the renal excretion of urea and electrolytes were studied in sheep, subjected to water stress, before and after 36-hour fasting. The intravenous administration of synthetic lysine-vasopressin (L-VP) at the dose of 100 microgram per kg induced only a temporary, statistically insignificant, drop of the urinary urea outputs by the fed as well as fasting sheep. L-VP did not influence the excretion of sodium and potassium electrolytes either.

[Biological titration of antidiuretic activity of ovine plasma].

We studied a relationship of the antidiuretic hormone to the level of urea in the ovine blood. An antidiuretic activity of the ovine blood plasma before and after 36-hour fasting was determined by biological titration on 22-day-old rats. Optimum control doses were calculated as follows: 1.

[The passage of nitrogenous compounds through the wall of perfused sheep rumen (author's transl)].

Experiments were performed by the method of the extracorporeal perfusion of sheep rumen lasting 150 minutes. After 60 minutes of perfusion, 20 g of enzymatic casein hydrolyzate were applied to the rumen. Ammonia, urea, and total nitrogen were determined in the samples of perfusate, and ammonia and pH were determined in the rumen content.

[Extracorporeal perfusion of the sheep rumen].

We constructed a modified perfusion apparatus and elaborated a method of extracorporal perfusion of the rumen of sheep. As perfusates we used the bovine plasma diluted in a ratio of 1:1 of an isotonic sodium chloride (NaCl) solution and the whole autologous blood. Transaminases GOT and GPT, ammonia and pH were determined in the perfusate.