Anti-Müllerian hormone (AMH), also known as Müllerian inhibiting substance (MIS), is expressed by granulosa cells in females of many mammalian species, and circulating AMH concentrations have been used to monitor granulosa-cell tumors (GCT) in women. The objective was to characterize expression of AMH in equine GCT, and in normal equine ovaries, based upon immunohistochemistry (IHC), using a polyclonal primary antibody directed against human AMH. Equine GCT (n = 27) and normal equine ovaries (n = 10) were examined by IHC. In addition, sera from four mares with GCT were characterized for AMH bioactivity, based upon suppression of Müllerian duct development in the fetal rat. Immunolabeling with α-AMH was localized to granulosa cells in equine GCT, as well as within antral follicles in normal ovaries. Expression of AMH first appeared in granulosa cells of small growing follicles and was most intense in small antral follicles; large antral or atretic follicles had reduced immunolabeling. Omission of the primary antibody or incubation of the primary antibody with the corresponding blocking peptide eliminated immunolabeling of granulosa cells in GCT and in normal antral follicles, confirming the specificity of the immunolabel. Sera from mares with GCT had increased AMH bioactivity compared to control sera. In conclusion, AMH was strongly expressed by granulosa cells in equine GCT and in normal antral follicles. Therefore, anti-Müllerian hormone may be a useful biomarker for detection of GCT in the horse.
|Number of pages||10|
|State||Published - Oct 1 2008|
Bibliographical noteFunding Information:
Supported by the John P. Hughes Endowment and the Center for Equine Health, with funds provided by the State of California Pari-mutuel Fund, and contributions by private donors. The authors thank Ms. Andrea Brum for assistance with immunohistochemistry, Dr. Anja Stoll and Dr. Alejandro Esteller Vico for providing some of the tissues used in this study, as well as Ms. Coralie Munro for assistance with endocrine assays.
- Anti-Müllerian hormone
- Granulosa-cell tumor
- Ovarian follicle
ASJC Scopus subject areas
- Small Animals
- Food Animals
- Animal Science and Zoology