Neurophysin I is an analytically robust surrogate biomarker for oxytocin
AuthorMacLean, Evan L.
Gnanadesikan, Gitanjali E.
King, Katherine M.
Allen, Alicia M.
Linde-Krieger, Linnea B.
White-Traut, Rosemary C.
Hammock, Elizabeth A.D.
Carter, C. Sue
Tecot, Stacey R.
Bell, Aleeca F.
AffiliationCollege of Veterinary Medicine, University of Arizona
Department of Psychology, University of Arizona
School of Anthropology, University of Arizona
Department of Family and Community Medicine, University of Arizona
Laboratory for the Evolutionary Endocrinology of Primates, University of Arizona
College of Nursing, University of Arizona
Psychiatry and Mental health
Endocrine and Autonomic Systems
Endocrinology, Diabetes and Metabolism
MetadataShow full item record
CitationMacLean, E. L., Carranza, E., Gnanadesikan, G. E., King, K. M., Allen, A. M., Linde-Krieger, L. B., ... & Bell, A. F. (2023). Neurophysin I is an Analytically Robust Surrogate Biomarker for Oxytocin. Psychoneuroendocrinology, 106951.
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AbstractOxytocin is a pleiotropic neuropeptide that plays roles in biological processes ranging from birth, lactation, and social bonding to immune function, cardiovascular repair, and regulation of appetite. Although measurements of endogenous oxytocin concentrations have been performed for more than 50 years, the ability to measure oxytocin accurately poses notable challenges. One potential solution for overcoming these challenges involves measurement of oxytocin's carrier molecule – neurophysin I (NP-1) – as a surrogate biomarker. NP-1 is secreted in equimolar concentrations with oxytocin but has a longer half-life, circulates in higher concentrations, and can be measured using a sandwich immunoassay. We report experiments that 1) analytically validate a commercially available NP-1 sandwich immunoassay for use with human plasma and urine samples, 2) confirm the specificity of this assay, based on detection of NP-1 in plasma from wild-type but not oxytocin knockout mice, 3) demonstrate that NP-1 concentrations are markedly elevated in late pregnancy, consistent with studies showing substantial increases in plasma oxytocin throughout gestation, and 4) establish strong correlation between NP-1 and plasma oxytocin concentrations when oxytocin is measured in extracted (but not non-extracted) plasma. The NP-1 assay used in this study has strong analytical properties, does not require time-intensive extraction protocols, and the assay itself can be completed in < 2 h (compared to 16–24 h for a competitive oxytocin immunoassay). Our findings suggest that much like copeptin has become a useful surrogate biomarker in studies of vasopressin, measurements of NP-1 have similar potential to advance oxytocin research.
Note12 month embargo; first published 30 December 2023
VersionFinal accepted manuscript
SponsorsNational Institute of Nursing Research