Validation of a radioimmunoassay for measurement of gastrin in equine serum.

This research validates the use of a commercially available radioimmunoassay kit initially designed for measuring gastrin levels in human serum for use in horses. The performance of the kit was tested and yielded high accuracy and consistent results, with some considerations around the use of certain substances that may affect results.

Validation of Radioimmunoassay Kit

• An existing commercial radioimmunoassay kit, created initially for measuring the levels of gastrin in human serum, was tested for validity with equine (horse) serum. Gastrin is a hormone that stimulates the production of gastric acid, which is crucial for digestion.
• The kit uses a double-antibody procedure, meaning two different antibodies are used in the testing process, enhancing the accuracy and sensitivity of the test.
• The researchers validated the assay procedure by comparing the assayed gastrin values with the added mass of synthetic gastrin (G17-I) to equine serum, showing a recovery rate of 99 to 115%. This indicates a high level of accuracy in the measurement of gastrin concentration.

Test Outcomes and Variations

• The behavior of gastrin in postprandial equine serum (serum after feeding) was also tested and yielded consistent results. The dilution plots were comparable to those of the human test gauges.
• Nonetheless, two substances, ethylenediamine tetraacetate and heparin, were found to adversely affect the assay by decreasing the detected gastrin concentration. These substances should therefore be avoided when using this kit for equine serum gastrin assessment.
• The assay’s intra-assay coefficient of variation, which shows the degree of variation in the results of several runs of the same sample on the kit, was 3.8%. The interassay coefficient of variation, on the other hand, measuring variations between separate runs of different samples, was 11.2%.

Gastrin Concentration in Fasting and Postprandial Serum

• The gastrin concentration in serum from fasting horses ranged from undetectable (less than 8 pg/ml) to 17.5 pg/ml, and after feeding, peaked at a mean value of 70 pg/ml. This indicates the utility of the radioimmunoassay for studying the effects of feeding on gastrin levels in horses.
• During these tests, serum cortisol values were monitored and found to be within the normal range for horses, indicating that the feeding and fasting did not induce undue stress in the test subjects.

Overall, this study confirms the reliability and applicability of this commercially available radioimmunoassay kit for measuring gastrin levels in equine serum, with some considerations around substances that might interfere with the results.