Abstract

Oxytocin is a hormone with functions in: reproduction, maternal bonding, milk ejection, and feeding/social behavior, and is reported to be present in a variety of tissues. Our goal is to characterize oxytocin and leucyl and cystinyl aminopeptidase (LNPEP/oxytocinase), a key regulator of oxytocin in mares. We measured serum and tissue LNPEP by ELISA from ovulation (D0) until D21–22 in non-pregnant (n = 5) and pregnant mares (n = 6); and in periparturient and postpartum mares (n = 18). Placenta (n = 7) and homogenized tissue of diestrus mares (n = 6) were evaluated using protein determinations and LNPEP ELISAs. Identification of LNPEP and OXT protein in tissues was also performed via western blot, immunohistochemistry and liquid chromatography-mass spectrometry (LC-MS/MS). Furthermore, in situ hybridization was performed for LNPEP and OXT on endometrium, myometrium, pituitary and corpus luteum (CL). Serum LNPEP concentration were similar. Placental LNPEP U/mg protein was highest in the body and pregnant horn. The highest to lowest LNPEP U/mg protein by tissue were: myometrium > follicle wall > endometrium > kidney > CL > liver. Oxytocin was identified in the equine pituitary, CL and placenta and is likely to act in autocrine or paracrine manner, while LNPEP may act systemically and locally to regulate the availability of OXT.

Details

Title
Characterization of serum and tissue oxytocinase and tissue oxytocin in the pregnant and non-pregnant mare
Author
Diel de Amorim, Mariana 1 ; Dong, Lynn 2 ; Byron, Michael 1 ; Foster, Robert A. 3 ; Klein, Claudia 4 ; Saleh, Monique 5 ; Saleh, Tarek 5 ; Card, Claire 6 

 Cornell University, Department of Clinical Sciences, Ithaca, USA (GRID:grid.5386.8) (ISNI:000000041936877X) 
 Cornell University, Immunopathology Research and Development Laboratory, Department of Biomedical Sciences, Ithaca, USA (GRID:grid.5386.8) (ISNI:000000041936877X); Bristol Myers Squibb, Translational Pathology, Princeton, USA (GRID:grid.419971.3) (ISNI:0000 0004 0374 8313) 
 University of Guelph, Department of Pathobiology, Ontario Veterinary College, Guelph, Canada (GRID:grid.34429.38) (ISNI:0000 0004 1936 8198) 
 University of Calgary, Department of Veterinary Clinical and Diagnostic Science, Calgary, Canada (GRID:grid.22072.35) (ISNI:0000 0004 1936 7697); Institute of Farm Animal Genetics, Federal Research Institute for Animal Health, Neustadt-Mariense, Germany (GRID:grid.417834.d) 
 University of Guelph, Department of Biomedical Sciences, Ontario Veterinary College, Guelph, Canada (GRID:grid.34429.38) (ISNI:0000 0004 1936 8198) 
 Western College of Veterinary Medicine, Department of Large Animal Clinical Sciences, Saskatoon, Canada (GRID:grid.25152.31) (ISNI:0000 0001 2154 235X) 
Pages
4616
Publication year
2023
Publication date
2023
Publisher
Nature Publishing Group
e-ISSN
20452322
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2789150654
Copyright
© The Author(s) 2023. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.