Cyclic 3’,5’-Adenosine Monophosphate Mediates Dopamine D1-Stimulated Growth Hormone Release from Goldfish Pituitary Cells
Bibliographic record
Abstract
Previously, we have demonstrated that dopamine (DA) stimulates growth hormone (GH) release from the goldfish pituitary through DA D1 receptors. In the present study, the role of cAMP in DA D1-stimulated GH release was investigated using static incubation of goldfish pituitary cells. The D1 agonist SKF38393 (1 nM-10 microM) induced GH release and cAMP accumulation in a dose-dependent manner with ED50s of 73 +/- 32 and 109 +/- 53 nM, respectively. In contrast, the D2 agonist LY171555 (1 nM-10 microM) was not effective in these regards. The GH-releasing action of SKF38393 was mimicked by the adenylate cyclase activator forskolin (0.1-40 microM) as well as the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (0.1 microM-1 mM). Dideoxyforskolin (0.1-40 microM), a derivative of forskolin inactive in stimulating adenylate cyclase, did not affect basal GH secretion. Similar stimulatory effects on GH release were also observed using the membrane-permeant cAMP analogs (10 microM-2 mM), dibutyryl cAMP and 8-bromo cAMP (8Br.cAMP). In the presence of a high dose (1 mM) of Br.cAMP, the ability of SKF38393 (1 nM-10 microM) to stimulate GH release was abolished, suggesting that the GH-releasing actions of cAMP and DA D1 stimulation are mediated through a common signal transduction mechanism. In the present study, the possible involvement of the cAMP-dependent enzyme protein kinase A (PKA) in DA D1-stimulated GH release was also examined. The GH responses to 8Br.cAMP (1 mM) and SKF38393 (1 microM) were blocked by simultaneous treatment with the PKA inhibitor H89 (10 microM).(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 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".