The Ovary Has Its Own Opioid Receptors That Change During the Menstrual Cycle

Opioid receptors found on pig ovarian granulosa cells and corpora lutea increased during follicular maturation, directly linking opioids to ovarian function.

Hamada, H et al.·European journal of endocrinology·1995·Preliminary Evidencein-vitro
RPEP-00322In VitroPreliminary Evidence1995RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
in-vitro
Evidence
Preliminary Evidence
Sample
Not reported

What This Study Found

Specific opioid receptors were found in pig granulosa cells and corpora lutea, with receptor numbers increasing during follicular maturation.

Key Numbers

How They Did This

Radioligand binding using [3H]naloxone in porcine granulosa cells and corpus luteum subcellular fractions. Competition binding with beta-endorphin, met-enkephalin, and dynorphin.

Why This Research Matters

Finding opioid receptors directly in the ovary means opioid peptides can regulate fertility at the organ level, not just through the brain. This has implications for understanding how opioid drugs affect reproductive function.

The Bigger Picture

Finding opioid receptors directly on the ovary adds a new level to understanding opioid effects on fertility. Opioid drugs could affect egg maturation directly, not just through hormonal changes.

What This Study Doesn't Tell Us

In vitro binding study in pig tissue. The functional significance of these receptors and their relevance to human ovarian biology need further study.

Questions This Raises

  • ?Do opioid drugs directly impair egg quality through these ovarian receptors?
  • ?Could ovarian opioid receptors be targeted for fertility treatment?

Trust & Context

Key Stat:
Cycle-dependent Ovarian opioid receptor numbers increased during follicular maturation, suggesting dynamic opioid regulation of egg development
Evidence Grade:
Preliminary — in vitro binding study in pig ovarian tissue. Functional significance not determined.
Study Age:
Published in 1995 (31 years ago). Ovarian opioid receptors have since been confirmed in multiple species.
Original Title:
[3H]naloxone binding sites in porcine ovarian follicles and corpora lutea during the ovarian cycle.
Published In:
European journal of endocrinology, 132(5), 622-6 (1995)
Database ID:
RPEP-00322

Evidence Hierarchy

Meta-Analysis / Systematic Review
Randomized Controlled Trial
Cohort / Case-Control
Cross-Sectional / ObservationalSnapshot without intervening
This study
Case Report / Animal Study
What do these levels mean? →

Frequently Asked Questions

Can opioid drugs directly affect the ovaries?

This study suggests yes — opioid receptors are present directly on ovarian cells, and their numbers change during the cycle. This means opioid drugs could affect egg maturation at the ovarian level, independent of brain hormonal effects.

Why do opioid receptors increase during egg maturation?

It suggests opioid signaling plays a role in the ovulation process. The increasing receptor numbers during maturation may help fine-tune the timing and quality of egg release.

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Cite This Study

RPEP-00322·https://rethinkpeptides.com/research/RPEP-00322

APA

Hamada, H; Kishioka, S; Yamoto, M; Nakano, R. (1995). [3H]naloxone binding sites in porcine ovarian follicles and corpora lutea during the ovarian cycle.. European journal of endocrinology, 132(5), 622-6.

MLA

Hamada, H, et al. "[3H]naloxone binding sites in porcine ovarian follicles and corpora lutea during the ovarian cycle.." European journal of endocrinology, 1995.

RethinkPeptides

RethinkPeptides Research Database. "[3H]naloxone binding sites in porcine ovarian follicles and ..." RPEP-00322. Retrieved from https://rethinkpeptides.com/research/hamada-1995-3hnaloxone-binding-sites-in

Access the Original Study

Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.

This study breakdown was produced by the RethinkPeptides research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.