B-Type Natriuretic Peptide Receptor Expression and Activity Are Hormonally Regulated in Rat Ovarian Cells1
Bibliographic record
Abstract
Natriuretic peptides form a family of structurally related peptides known to regulate salt and water homeostasis and to cause vasodilation. Synthesis of atrial (ANP), brain (BNP), and C-type (CNP) natriuretic peptides occurs mainly in the heart and brain and has been identified recently in the female reproductive tract. The expression of ANP and CNP as well as their cognate guanylyl cyclase receptors (NPR-A and NPR-B, respectively) have been detected in the rat ovary. We have shown previously that the expression of the natriuretic peptides and their receptors in the rat ovary appears to be modulated by the estrous cycle. In the present study we have evaluated the expression of the natriuretic peptide system (peptide and receptor) in ovarian cells (granulosa and thecal-interstitial cells) obtained from immature female rats treated with either diethylstilbestrol (DES), an estrogen analog, or equine CG (eCG), a gonadotropin that possesses both LH and FSH activity. Using a whole cell RRA, we found that CNP binding was increased by 2-fold in granulosa cells taken from animals treated with either DES or eCG. Semiquantitative RT-PCR revealed that granulosa cells from DES- or eCG-treated animals have increased levels of NPR-B messenger RNA (mRNA) transcripts, which was in good agreement with the increased binding. The activity of the receptors was assessed by ligand-dependent stimulation of cGMP release. CNP, but not ANP, stimulated the release of cGMP from granulosa cells obtained from DES-treated, but not from eCG-treated, animals. The relative levels of CNP mRNA in granulosa cells were unaltered by either DES or eCG treatment. In contrast, CNP mRNA levels were increased more than 2-fold, but only in theca-interstitial from the eCG-treated animals. Our results indicate that CNP and NPR-B are expressed in the ovary, and their expression is responsive to hormonal treatments. Furthermore, expression of these components of the natriuretic peptide system appears to be compartmentalized, with CNP being derived from the extrafollicular compartment and acting, through NPR-B, on the granulosa cells.
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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 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".