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Record W1990368239 · doi:10.1152/ajpregu.00376.2003

Divergent gonadotropin-gonadal dose-responsive coupling in healthy young and aging men

2004· article· en· W1990368239 on OpenAlex
Daniel M. Keenan, Johannes D. Veldhuis

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

affAt least one author lists a Canadian institution in the pinned OpenAlex snapshot.

Bibliographic record

VenueAmerican Journal of Physiology-Regulatory, Integrative and Comparative Physiology · 2004
Typearticle
Languageen
FieldMedicine
TopicHypothalamic control of reproductive hormones
Canadian institutionsInstitute of Nutrition, Metabolism and Diabetes
FundersNational Center for Research ResourcesNational Institute on Aging
KeywordsEndocrinologyInternal medicineGonadotropinLuteinizing hormonePulsatile flowTestosterone (patch)Median eminenceChemistryBiologyHormoneMedicine

Abstract

fetched live from OpenAlex

The present study extends a recent composite model of in vivo interglandular signaling to assess the impact of age on 1) nonequilibrium exchange among diffusible and protein-bound testosterone (Te); 2) elimination of total and free Te; 3) basal and pulsatile Te secretion (sec); 4) the implicit feedforward function mediating luteinizing hormone (LH) concentration (con) drive of instantaneous Te sec; and 5) possible stochastic variability of the predicted LH con-Te sec dose-response linkage. To this end, we measured LH and Te con every 10 min for 24 h in healthy young (n = 13) and older men (n = 13). Statistical comparisons of analytic estimates revealed that elderly subjects manifest 1) reduced maximal burstlike LH-stimulated Te sec (impaired stimulus efficacy); 2) depressed half-maximally LH-stimulated Te sec (lower Leydig-cell responsivity); 3) decreased pulsatile and total Te sec; 4) elevated basal Te sec; 5) a prolonged half-life of total but not free Te con; and 6) delayed time evolution of LH and Te sec bursts. In contradistinction, age did not influence estimated LH-pulse potency (ED50), steroidogenic sensitivity (slope term), or stochastic variability of LH-Te coupling. On the basis of these data, we postulate that aging in the human male alters specific dose-response attributes linking LH con and Te sec and disrupts the time waveform of LH and Te sec bursts.

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.

Full frame distilled prediction

Teacher imitation

Not 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.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesMeta-epidemiology (narrow)
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Bench or experimental · Consensus signal: none
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.963
Threshold uncertainty score1.000

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0020.000
Bibliometrics0.0000.000
Science and technology studies0.0000.002
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.001
Insufficient payload (model declined to judge)0.0000.000

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.

Opus teacher head0.021
GPT teacher head0.299
Teacher spread0.278 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it