Detection of Serum Anti-Müllerian Hormone Concentrations as a Method for Diagnosis of Cryptorchidism in the Horse

1. Introduction

Cryptorchidism, particularly in previously castrated geldings, remains a diagnostic challenge for the equine practitioner. Measurement of testosterone (with or without human chorionic gonadotropin [hCG] stimulation) and/or estrone sulphate is the most convenient diagnostic method for the equine practitioner. We have shown previously that anti-Müllerian hormone (AMH) is expressed by the Sertoli cells in cryptorchid equine testes, and the objective of this study was to determine serum concentrations of AMH in geldings, cryptorchids, and stallions.

2. Materials and Methods

Serum samples from geldings (n = 48), cryptorchids (n = 44), and stallions (n = 15) from the clinical endocrinology laboratory and the Veterinary Medical Teaching Hospital at the University of California at Davis were used in this study. Horses were classified as gelding, cryptorchid, or intact stallion according to their history and serum testosterone concentrations. Serum AMH concentrations were measured with a heterologous enzyme immunoassay (active AMH–enzyme-linked immunosorbent assay^a). Differences in serum AMH concentrations were compared using Student t tests.

3. Results and Discussion

Serum concentrations of AMH were higher (p < 0.01) in cryptorchids (32.4 ± 5.0 ng/ml) than in stallions (14.7 ± 2.4 ng/ml) or geldings (0.07 ± 0.01 ng/ml). Serum AMH concentrations were also higher (p < 0.02) in stallions than in geldings. Serum AMH concentrations are a useful biomarker for the presence of testicular tissue in the stallion, and concentrations of AMH are higher in cryptorchids than in either geldings or stallions.

This work was supported by the John P. Hughes Endowment and the Clinical Endocrinology Laboratory, University of California, Davis, CA.

Footnote

^a ELISA, Diagnostic Systems Laboratories, Webster, TX 77598.