[Various protocols for determining estrogens by the enzymatic method using estradiol dehydrogenase. Respective...

Area of Science:

• Clinical Biochemistry
• Enzyme Assays

Background:

• Over 40,000 urinary estrogen (E1 + E2) determinations have been performed using enzymatic methods.
• Estradiol dehydrogenase utilizes transhydrogenating activity for NADP to NAD conversion, recycling the substrate.

Purpose of the Study:

• To detail improvements in measuring reduced NAD, which is proportional to estrogen concentration.
• To present three distinct protocols for enzymatic urinary estrogen analysis.

Main Methods:

• Spectrophotometric measurement at 340 nm (original method).
• Colorimetric measurement at 492 nm using a tetrazolium salt (INT) and diaphorase.
• Bioluminescence assay measuring light energy from NADH reduction via marine bacterial enzymes and decanal.

Main Results:

• All three protocols allow for the measurement of reduced NAD, directly correlating with estrogen levels.
• Procedures for each protocol and linearity control methods are described.
• The choice of protocol depends on biological sample, desired speed, and cost.

Conclusions:

• The enzymatic method for urinary estrogen determination is well-established and refined.
• Multiple detection methods offer flexibility for clinical laboratories.
• Optimization of reduced NAD measurement enhances assay accuracy and applicability.