Dynorphin Causes a 5-Fold Prolactin Surge in Turkey Hens Through Kappa Receptors
Big dynorphin infused into turkey brains caused a 5.1-fold increase in prolactin through kappa opioid receptors, relevant to incubation behavior.
Quick Facts
What This Study Found
Big dynorphin (prodynorphin 209-240) caused a 5.1-fold increase in serum prolactin in turkeys, mediated through kappa opioid receptors.
Key Numbers
How They Did This
Researchers infused opioid peptides (big dynorphin, dynorphin A, dynorphin B, beta-endorphin, met-enkephalin) into the third ventricle of anesthetized laying turkey hens and measured serum prolactin levels.
Why This Research Matters
Prolactin controls incubation behavior in birds and has wide-ranging hormonal effects in mammals. Understanding opioid control of prolactin helps explain how peptides regulate hormone systems.
The Bigger Picture
Prolactin has wide-ranging effects from lactation to immune function. Understanding its opioid regulation in an evolutionary model reveals how ancient this control system is.
What This Study Doesn't Tell Us
Animal study in turkeys, not mammals. Used direct brain injection under anesthesia. Results may not apply to mammalian prolactin regulation or natural conditions.
Questions This Raises
- ?Is dynorphin-driven prolactin release conserved in mammals?
- ?Could this pathway explain some opioid drug side effects on prolactin?
Trust & Context
- Key Stat:
- 5.1-fold increase Big dynorphin caused the largest prolactin response of any peptide tested — a dramatic surge through kappa receptors
- Evidence Grade:
- Preliminary — animal study in anesthetized turkey hens with ICV infusion. Shows clear effect but in an avian model under anesthesia.
- Study Age:
- Published in 1993 (33 years ago). Opioid regulation of prolactin is now well-characterized in both birds and mammals.
- Original Title:
- Dynorphin modulates prolactin secretion in the turkey.
- Published In:
- General and comparative endocrinology, 91(2), 224-31 (1993)
- Authors:
- Youngren, O M, Silsby, J L, Phillips, R E, el Halawani, M E
- Database ID:
- RPEP-00284
Evidence Hierarchy
Tests effects in animals (usually mice or rats), not humans.
What do these levels mean? →Frequently Asked Questions
Why study prolactin in turkeys?
Prolactin drives incubation behavior in birds — it's the hormone that makes hens sit on eggs. Understanding its regulation reveals fundamental neuroendocrine mechanisms conserved across species.
Does this apply to humans?
Yes — kappa opioid receptor activation increases prolactin in mammals too. This helps explain why some opioid drugs cause elevated prolactin, leading to side effects like breast growth and lactation issues.
Read More on RethinkPeptides
Cite This Study
https://rethinkpeptides.com/research/RPEP-00284APA
Youngren, O M; Silsby, J L; Phillips, R E; el Halawani, M E. (1993). Dynorphin modulates prolactin secretion in the turkey.. General and comparative endocrinology, 91(2), 224-31.
MLA
Youngren, O M, et al. "Dynorphin modulates prolactin secretion in the turkey.." General and comparative endocrinology, 1993.
RethinkPeptides
RethinkPeptides Research Database. "Dynorphin modulates prolactin secretion in the turkey." RPEP-00284. Retrieved from https://rethinkpeptides.com/research/youngren-1993-dynorphin-modulates-prolactin-secretion
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.