Students' Research Circle    
» 2013
Call for papers
The conference
Veterinary Session
Veterinary Jury
Home » Archive » 2013

TDK conference 2013

The effect of increased salt intake on urinary endothelin in dogs
Falus Fruzsina Anna - graduating student
SzIU, Faculty of Veterinary Science, Department and Clinic for Internal Medicine
Supervisor: Manczur Ferenc DVM


Endothelins are 21 amino-acid vasoactive proteins, among them endothelin-1 is known as the most potent vasoconstrictor molecule. Endothelins can be detected in a wide variety of human and animal tissues where they take part in different physiological and pathophysiological processes. The highest concentration of endothelins and their receptors can be found in the kidneys, especially in the inner medulla.

It is known that the urinary endothelin originates almost exclusively from the kidneys (and not from the systemic circulation) and the urinary endothelin excretion increase in various kidney disorders. Hence, this parameter could have an important role in the diagnosis or prognosis of different nephropathies. As endothelins have a great role in the physiological regulation of volume and salt homeostasis in the kidney, it is logical to assume that urinary endothelin concentration may correlate with the urinary salt excretion. The aim of my research was to investigate whether the salt content of the food influences the endothelin concentration of the urine. If it was true, any found association between nephropathies and urinary endothelin concentration should be viewed after allowing adjustments for the salt content of the food.

To investigate the association between the food salt content and the urinary endothelin concentration I performed two experiments. In the first one I fed high salt diet to four healthy beagle dogs for two weeks and the control group consisted of four other beagles. The salt content of the diet was approximately five times more than in an average dog food and three-quarters of the recommended safe upper limit. I took blood and urine samples at the beginning and at the end of the study. The second experiment was a crossover study with four healthy beagles, where two beagle dogs were on the high salt diet and two were fed their normal diet for a week and then the two groups were reversed. I obtained blood and urine samples three times during this trial. I compared serum creatinine, sodium and potassium levels, while I measured the specific gravity, protein, creatinine, sodium, potassium and endothelin levels from the urine samples. In addition I also determined the sodium/creatinine and endothelin/creatinine ratios and the fractional excretion of sodium.

I found no association between the urine endothelin and sodium levels. Moreover the high salt diet fed in theses studies was not able to increase the urine sodium excretion. Based on these results it can be concluded that the urinary endothelin concentration is not affected by the salt content of the pet foods, thus the urinary endothelin concentration is probably determined by other physiological or pathophysiological parameters.

List of lectures