The Body's Own Cannabis System May Help Regulate Fertility
Researchers discovered the endocannabinoid anandamide in human reproductive fluids and found that both anandamide analogues and THC altered sperm capacitation and fertilizing potential, suggesting cannabis use could affect fertility.
Quick Facts
What This Study Found
Anandamide, an endocannabinoid, was detected in human seminal plasma, mid-cycle oviductal fluid, and follicular fluid. Human sperm expressed cannabinoid receptors with specific, saturable binding. A metabolically stable anandamide analogue produced dose-dependent effects on sperm: at higher concentrations (2.5 nM) it inhibited hyperactivated motility, while at lower concentrations (0.25 nM) it stimulated it.
Both the anandamide analogue and THC inhibited acrosomal changes needed for fertilization at remarkably low concentrations. Sperm fertilizing capacity in the Hemizona Assay was reduced 50% by just 1 nM of the anandamide analogue. These findings suggested that the endocannabinoid system plays a natural regulatory role in fertility, and that cannabis use could disrupt this regulation.
Key Numbers
Cannabinoid receptor binding: KD 9.71 nM on sperm. Anandamide analogue: inhibited hyperactivated motility at 2.5 nM, stimulated at 0.25 nM. Acrosomal changes inhibited at IC50 of 5.9 pM (analogue) and 3.5 nM (THC). Fertilizing capacity reduced 50% at 1 nM.
How They Did This
This was a laboratory study using human reproductive fluids analyzed by HPLC/mass spectrometry to detect anandamide. Cannabinoid receptor binding on human sperm was characterized using radioligand binding assays. Functional effects of cannabinoid agonists and THC on sperm capacitation, hyperactivated motility, acrosomal changes, and fertilizing potential were assessed in vitro.
Why This Research Matters
This study provided the first evidence that the endocannabinoid system was present and active in human reproductive fluids and sperm. The finding that very low concentrations of cannabinoids could significantly impair sperm fertilizing capacity raised important questions about cannabis use and male fertility.
The Bigger Picture
This study opened a new field of research into endocannabinoid regulation of fertility. Subsequent studies have confirmed endocannabinoid involvement in implantation, placentation, and early pregnancy. The implications for cannabis users trying to conceive have become more clinically relevant as cannabis use has increased.
What This Study Doesn't Tell Us
All functional experiments were conducted in vitro and may not directly reflect conditions in the reproductive tract. The concentrations of anandamide in reproductive fluids and the concentrations of THC that would reach sperm after cannabis use may differ from those tested. The study did not assess female fertility parameters.
Questions This Raises
- ?Do THC concentrations in the reproductive tract of cannabis users reach levels sufficient to affect sperm function?
- ?Does chronic cannabis use alter endocannabinoid levels in reproductive fluids?
- ?How does the endocannabinoid system interact with other hormonal regulators of fertility?
Trust & Context
- Key Stat:
- Sperm fertilizing capacity cut 50% at just 1 nM cannabinoid concentration
- Evidence Grade:
- This is an in vitro laboratory study providing preliminary evidence of a mechanism that requires in vivo confirmation.
- Study Age:
- Published in 2002. Subsequent research has confirmed endocannabinoid involvement in reproductive function.
- Original Title:
- Evidence that anandamide-signaling regulates human sperm functions required for fertilization.
- Published In:
- Molecular reproduction and development, 63(3), 376-87 (2002)
- Authors:
- Schuel, Herbert, Burkman, Lani J, Lippes, Jack, Crickard, Kent, Mahony, Mary C, Giuffrida, Andrea, Picone, Robert P, Makriyannis, Alexandros
- Database ID:
- RTHC-00129
Evidence Hierarchy
Watches what happens naturally without intervening.
What do these levels mean? →Frequently Asked Questions
Can cannabis affect male fertility?
This study showed that cannabinoid compounds significantly impaired sperm function at very low concentrations in the lab. Whether typical cannabis use produces sufficient THC levels in reproductive fluids to cause these effects in real life requires further study.
What does the body's endocannabinoid system do in reproduction?
The researchers found that anandamide, a natural endocannabinoid, was present in seminal fluid, oviductal fluid, and follicular fluid, suggesting it plays a role in regulating the fertilization process. This natural regulation could be disrupted by external cannabinoids from cannabis use.
Read More on RethinkTHC
Cite This Study
https://rethinkthc.com/research/RTHC-00129APA
Schuel, Herbert; Burkman, Lani J; Lippes, Jack; Crickard, Kent; Mahony, Mary C; Giuffrida, Andrea; Picone, Robert P; Makriyannis, Alexandros. (2002). Evidence that anandamide-signaling regulates human sperm functions required for fertilization.. Molecular reproduction and development, 63(3), 376-87.
MLA
Schuel, Herbert, et al. "Evidence that anandamide-signaling regulates human sperm functions required for fertilization.." Molecular reproduction and development, 2002.
RethinkTHC
RethinkTHC Research Database. "Evidence that anandamide-signaling regulates human sperm fun..." RTHC-00129. Retrieved from https://rethinkthc.com/research/schuel-2002-evidence-that-anandamidesignaling-regulates
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 RethinkTHC 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.