Continuous Administration of Human Corticotropin-Releasing Hormone in the Absence of Glucocorticoid Feedback in Man
Bibliographic record
Abstract
Continuous 24-hour infusions of a maximally stimulating dose (1 microgram/kg/h) of corticotropin-releasing hormone (CRH) have been shown to cause elevations of plasma cortisol and ACTH, but the pattern of results were confounded by serum cortisol causing feedback changes. We have looked at ACTH responses to saline or CRH infusions over 24 h in 6 normal subjects who, in addition, received either placebo or metyrapone, an 11 beta-hydroxylase inhibitor which blocks the formation of cortisol and thus abolishes glucocorticoid feedback. Cortisol and ACTH levels were measured by radioimmunoassay. Before metyrapone, CRH infusion resulted in exaggerated ACTH peaks throughout the day, as compared with normal saline: there was no influence on the noctural rise in ACTH. Following metyrapone alone, absolute cortisol levels were lower but circadian rhythmicity was preserved. Circadian rhythm of ACTH was maintained, with a fall in the evening to 14.5 +/- 4 pg/ml (mean +/- SE) at midnight and an exaggerated rise overnight, reaching a peak level of 90 +/- 33 pg/ml at 07:00 h. Subjects receiving CRH with metyrapone showed a similar pattern of responses, but with further enhanced ACTH levels. The evening fall reached a nadir of 30 +/- 6 pg/ml at 01:00 h. With diminished glucocorticoid feedback the nocturnal rise in ACTH was augmented by CRH infusion, with a morning peak of 193 +/- 21 pg/ml at 07:00 h. Thus, continuous infusion of CRH in the absence of steroid feedback leads to a retention of the circadian rhythmicity in ACTH secretion, reset at a higher absolute level.(ABSTRACT TRUNCATED AT 250 WORDS)
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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 source (direct Gemma or distilled Codex), 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".