1. Human sperm cells can form paracetamol metabolite AM404 that directly interferes with sperm calcium signalling and function through a CatSper-dependent mechanism
- Author
-
Rehfeld, A, Frederiksen, H., Rasmussen, R. H., David, A., Chaker, J., Nielsen, B. S., Nielsen, J. E., Juul, A, Skakkebæk, N. E., Kristensen, D. M., Rehfeld, A, Frederiksen, H., Rasmussen, R. H., David, A., Chaker, J., Nielsen, B. S., Nielsen, J. E., Juul, A, Skakkebæk, N. E., and Kristensen, D. M.
- Abstract
STUDY QUESTION: Do paracetamol (N-acetyl-para-aminophenol (APAP) or acetaminophen) and/or its metabolites affect human sperm Ca2+-signalling and function?SUMMARY ANSWER: While APAP itself does not interact with Ca2+-signalling in human sperm, its metabolite N-arachidonoyl phenolamine (AM404), produced via fatty acid amide hydrolase (FAAH), interferes with human sperm Ca2+-signalling and function through a suggested CatSper channel-dependent action.WHAT IS KNOWN ALREADY: Studies have shown that adult men with high urinary levels of over-the-counter mild analgesic APAP have impaired sperm motility and increased time-to-pregnancy.STUDY DESIGN, SIZE, DURATION: This study consists of (i) an in vivo human pharmaceutical APAP exposure experiment to understand to what degree APAP reaches the sperm cells in the seminal fluid; (ii) in vitro calcium imaging and functional experiments in freshly donated human sperm cells to investigate CatSper channel-dependent activation by APAP and its metabolites; and (iii) experiments to understand the in situ capabilities of human sperm cells to form APAP metabolite AM404.PARTICIPANTS/MATERIALS, SETTING, METHODS: Three healthy young males participated in the in vivo human exposure experiment after prior consent. Human semen samples were provided by healthy young volunteer donors after prior consent on the day of the in vitro experiments.MAIN RESULTS AND THE ROLE OF CHANCE: Pharmaceutical APAP exposure reaches the seminal plasma in high micromolar concentrations and accumulates in the seminal plasma between 3 and 5 days of exposure (P-value 0.023). APAP and its primary metabolite 4-aminophenol (4AP) do not interact with human sperm Ca2+-signalling. Instead, the APAP metabolite AM404 produced via FAAH interferes with human sperm Ca2+-signalling through a CatSper-dependent action. Also, AM404 significantly increases sperm cell penetration into viscous mucous (P-value of 0.003). FAAH is functionally expres
- Published
- 2022