Uncoupling protein 2, but not uncoupling protein 1, is expressed in the female mouse reproductive tract

J Biol Chem. 2003 Nov 14;278(46):45843-7. doi: 10.1074/jbc.M306980200. Epub 2003 Aug 26.


Uncoupling proteins (UCPs) are transporters of the inner mitochondrial membrane. Whereas UCP1 is uniquely present in brown adipose tissue where it uncouples respiration from ATP synthesis and activates respiration and heat production, UCP2 is present in numerous tissues, and its exact function remains to be clarified. Two sets of data provided the rationale for this study: (i) the intriguing report that UCP1 is present in uterus of mice (Nibbelink, M., Moulin, K., Arnaud, E., Duval, C., Penicaud, L., and Casteilla, L. (2001) J. Biol. Chem. 276, 47291-47295); and (ii) an observation that Ucp2(-/-) female mice (homozygous matings) have smaller litters compared with Ucp2(+/+) animals (S. Rousset and A.-M. Cassard-Doulcier, unpublished observations). These data prompted us to examine the expression of UCP1 and UCP2 in the reproductive tract of female mice. Using wild type, Ucp1(-/-) mice, and Ucp2(-/-) mice, we were unable to detect UCP1 in uterus of mice with appropriate antibodies, and we conclude that the signal assigned to UCP1 by others was neither UCP1 nor UCP2. Using a polyclonal antibody against UCP2 and tissues from Ucp2(-/-) mice as controls, UCP2 was detected in ovary, oviduct, and uterus. Expression of Ucp2 mRNA was also observed in ovary and uterus using in situ hybridization analysis. Bone marrow transplantation experiments revealed that the UCP2 signal of the ovary was restricted to ovarian cells. UCP2 level in ovary decreased during follicular growth and increased during the pre-ovulatory period, during which aspects of an inflammatory process are known to exist. Because UCP2 down-regulates reactive oxygen species, a role in the regulation of inflammatory events linked to the preparation of ovulation is suggested.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / metabolism
  • Animals
  • Blotting, Western
  • Carrier Proteins / biosynthesis*
  • Female
  • In Situ Hybridization
  • Inflammation
  • Ion Channels
  • Membrane Proteins / biosynthesis*
  • Membrane Transport Proteins*
  • Mice
  • Mitochondrial Proteins*
  • Ovary / metabolism*
  • Oviducts / metabolism*
  • Ovulation
  • Pregnancy
  • Pregnancy, Animal
  • Protein Biosynthesis*
  • RNA, Messenger / metabolism
  • Reactive Oxygen Species
  • Time Factors
  • Tissue Distribution
  • Uncoupling Protein 1
  • Uncoupling Protein 2
  • Urogenital System
  • Uterus / metabolism*


  • Carrier Proteins
  • Ion Channels
  • Membrane Proteins
  • Membrane Transport Proteins
  • Mitochondrial Proteins
  • RNA, Messenger
  • Reactive Oxygen Species
  • Ucp1 protein, mouse
  • Ucp2 protein, mouse
  • Uncoupling Protein 1
  • Uncoupling Protein 2
  • Adenosine Triphosphate