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Origin of plasma androstanediol glucuronide in men
The Journal of Clinical Endocrinology and Metabolism
|September 1, 1984
Summary
Testosterone (T) and dihydrotestosterone (DHT) are precursors to androstanediol glucuronide (3 alpha diol G). DHT is a more direct precursor than T, suggesting a specific metabolic pathway for androgen formation.
Area of Science:
- Endocrinology
- Steroid Metabolism
- Biochemistry
Background:
- Testosterone (T) and dihydrotestosterone (DHT) are key androgens.
- Androstanediol glucuronide (3 alpha diol G) is a peripheral metabolite.
- Understanding precursor-metabolite relationships is crucial for hormonal studies.
Purpose of the Study:
- To investigate the roles of T and DHT as precursors to 3 alpha diol G in normal men.
- To elucidate the metabolic pathway leading to 3 alpha diol G formation.
- To clarify the significance of unconjugated 3 alpha diol levels in androgen disorders.
Main Methods:
- Constant intravenous infusions of 3H-labeled T and DHT in normal men.
- Measurement of unconjugated steroids and steroid glucuronides using chromatography.
- Calculation of conversion ratios (CR) to assess precursor-metabolite relationships.
Main Results:
- DHT was a more efficient precursor to 3 alpha diol G than T (CRDHT-3 alpha diol G was 10x higher than CRT-3 alpha diol G).
- The major conversion product of T was DHT glucuronide (DHTG), and the major product of DHT was 3 alpha diol G.
- Specific activities of 3 alpha diol and 3 alpha diol G differed, indicating distinct metabolic pools.
Conclusions:
- The metabolic pathway T → DHT → 3 alpha diol G is supported by the data.
- Peripheral 3 alpha diol G formation likely involves DHT glucuronide reduction.
- Blood levels of unconjugated 3 alpha diol may not accurately reflect androgen formation disorders due to differing origins.