Steroid determination in milk by enzyme immunoassay (EIA).

Area of Science:

• Biochemistry
• Endocrinology
• Veterinary Medicine

Background:

• Progesterone is a key hormone in reproductive cycles.
• Accurate progesterone measurement is crucial for monitoring reproductive health in livestock and humans.
• Existing assays can be complex and require sample extraction.

Purpose of the Study:

• To develop a simple and sensitive enzyme immunoassay (EIA) for progesterone using a homologous system.
• To adapt the EIA for direct measurement of progesterone in bovine milk, bypassing extraction.
• To validate the EIA's applicability to various biological samples, including human blood and saliva.

Main Methods:

• Development of a homologous enzyme immunoassay for progesterone.
• Optimization of incubation procedures to enhance assay sensitivity.
• Application of the EIA to analyze progesterone in bovine milk fat, bovine serum, human blood, and saliva extracts.
• Direct analysis of progesterone in bovine milk and human serum.

Main Results:

• The developed EIA accurately quantifies progesterone within the range of 30-3000 fmol/test tube (9.4-944 pg).
• Modified incubation procedures enabled direct progesterone measurement in cow milk without prior extraction.
• Milk fat did not interfere with the accuracy of progesterone measurements, preserving physiological relevance.
• The EIA demonstrated effectiveness in analyzing progesterone changes under various physiological, pathological, and therapeutic conditions.

Conclusions:

• A sensitive and straightforward homologous enzyme immunoassay for progesterone has been successfully developed.
• The EIA is suitable for direct progesterone analysis in bovine milk, simplifying sample processing.
• The assay provides reliable progesterone measurements in diverse biological matrices, supporting reproductive health assessments.