Suppression of Progesterone-Induced Gonadotropin Surge by Adrenergic Agonists in Estrogen-Primed Ovariectomized Rats
Bibliographic record
Abstract
An involvement of catecholamines in the preovulatory gonadotropin surge has been proposed for many years. Specifically, an alpha-adrenergic mechanism has been implicated in the stimulation of ovulation and LH release. On the other hand, little is known regarding the possible role of adrenergic neurotransmission once a gonadotropin surge has been initiated. In this study, drugs which affect adrenergic receptors were administered centrally to estrogen-primed ovariectomized rats and the effects on serum concentrations of LH and FSH induced by treatment with progesterone at 08:00 h were examined. As expected, the progesterone treatment caused a significant (p less than 0.05) increase in blood LH and FSH levels by 14:00 and 15:00 h, respectively, when compared with those seen at 13:00 h. In control rats that received isotonic saline intraventricularly at 15:00-16:00 h, both LH and FSH levels continued to rise linearly and reached peak levels by 17:00 and 18:00 h. By contrast, intraventricular infusion of norepinephrine at 16:00 h caused a significant decrease (p less than 0.05) in LH levels when compared with the saline-infused control groups. Moreover, rats that received intraventricular infusion of phenylephrine (an alpha 1-adrenergic agonist) at 15:00 h failed to show a significant increase in LH and FSH levels until 19:00 h; this inhibitory effect was mimicked by a relatively more specific alpha 1-adrenergic agonist, methoxamine. Consistent with our previous findings, animals which received intraventricular isoproterenol (a specific beta-adrenergic agonist) at 15:00 h also responded with suppressed serum LH levels at 16:00-19:00 h when compared with controls.(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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".