Further Insights Into the Metabolism of LGD‐4033 in Human Urine. Part 2. A New Minor Metabolite With Antagonistic Activity on the Androgen Receptor Can Indicate Recent Substance Intake
Bibliographic record
Abstract
ABSTRACT Using a targeted metabolic investigation approach, a new, previously undescribed metabolite, which is a pyrrole derivative of LGD‐4033, has been detected and coded as M8 . This metabolite can be detected in postadministration human urine samples up to 6 days after administration. It has also been detected in post‐administration samples, mimicking supplement contamination, after repeated 10 μg doses detectable for ≥ 120 h after administration. Given M8's structural similarity to LGD‐4033, its androgen receptor (AR) agonist/antagonist properties were studied using in silico molecular docking and functional in vitro AR transactivation assays in the PC3(AR) 2 cell model, alongside other selected LGD‐4033 metabolites. The results indicate that M8 can act as a potent AR antagonist, whereas M2c was reconfirmed as a potent AR agonist. Therefore, we propose the inclusion of M2c in ITP doping control methods, as it could be used as an LGD‐4033 alternative and may be introduced into the black market. Additionally, the detection of M8 , which is an early‐stage excreted metabolite, is valuable for estimating sample collection time relative to LGD‐4033 intake. When combined with the evaluation of other long‐term metabolites like M5b, M5a, M2c, and M2d, M8 detection can aid in distinguishing adverse analytical findings, associated abuse through regular dosing, from unintentional doping caused by certain contamination scenarios or abuse through microdosing.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".