Norandrosterone and noretiocholanolone concentration before and after submaximal standardized exercise

Area of Science:

• Exercise Physiology
• Sports Science
• Anti-doping Analysis

Background:

• 19-Norandrosterone (19-NA) and 19-noretiocholanolone (19-NE) are key urinary markers for nandrolone doping detection.
• Endogenous production of 19-NA and 19-NE in humans is possible, with levels near anti-doping thresholds.
• Eccentric exercise may influence androgen and estrogen biosynthesis, potentially affecting 19-norandrogen production.

Purpose of the Study:

• To investigate the influence of different exercise modalities on urinary 19-NA and 19-NE concentrations.
• To determine if eccentric exercise impacts endogenous 19-norandrogen excretion in healthy individuals.

Main Methods:

• Fifteen amateur hockey players performed standardized 30-minute submaximal exercise protocols.
• Exercise types included cycle ergometer (cyclic), treadmill (concentric), and bench-step (eccentric) tests.
• Urinary samples were collected pre-exercise and at 60 and 120 minutes post-exercise; muscle soreness was assessed.

Main Results:

• Baseline urinary 19-NA and 19-NE concentrations were below the limit of detection (0.05 ng/ml) in most samples.
• No 19-NA or 19-NE were detected in urine samples post-exercise across all tested modalities.
• Exercise mode (eccentric vs. concentric) did not significantly impact 19-NA or 19-NE excretion.

Conclusions:

• Under the experimental conditions, exercise type did not influence urinary 19-NA and 19-NE levels.
• The current International Olympic Committee threshold for nandrolone metabolites is robust against false positives from exercise.
• Further research may be needed to fully understand endogenous 19-norandrogen production during intense physical exertion.