Further studies on the diagnostic value of gamma-glutamyl transpeptidase and 5′-nucleotidase in cattle, sheep and horses.

This research paper reports on a study that examined the distribution and diagnostic value of two enzymes, 5′-nucleotidase and gamma-glutamyl transpeptidase, in the tissues of cattle, sheep, and horses, and their response to induced liver and kidney damage.

Enzymes and Tissue Distribution

• The researchers focused on two enzymes, gamma-glutamyl transpeptidase (gamma-GT), and 5′-nucleotidase (5′-NT). These enzymes, found in a variety of tissues, can sometimes be released into the blood plasma as response to organ damage.
• The study found that the distribution of these two enzymes in various body tissues was found to be similar across the three studied species – cattle, sheep, and horses. An exception was observed in the liver of the calves which was found to contain relatively lower amounts of gamma-GT as compared to the livers of sheep and horses.

Liver Damage and Enzyme Release

• Chloroform was orally administered to the animals to induce liver damage. The resultant liver damage was found to be similar across cattle, sheep, and horses.
• Following the liver damage, 5′-NT was released into the blood plasma of sheep and cattle, but not horses. In contrast, gamma-GT was released into the plasma of horses, but not in sheep or cattle. This difference in enzyme release was noted to be independent of their distribution in individual tissues.

Kidney Damage and Enzyme Activity

• In sheep, kidney damage was induced using mercuric chloride administered intravenously. This damage was accompanied by a decreased rate of excretion of inulin (a measure of kidney function), an increased concentration of urea in the plasma (another indicator of impaired kidney function), and an increased activity of gamma-GT in both plasma and urine.
• In contrast, no increase in 5′-NT activity was observed in either the plasma or urine, suggesting that gamma-GT might be a more relevant enzyme for monitoring kidney function.