Idiopathic infertility degeneration has been associated with altered e
ndocrine function in stallions. Therapy with gonadotropin releasing ho
rmone (GnRH) has been used in an attempt to correct these endocrine im
balances and thereby improve fertility. This article describes the phy
siologic basis of GnRH therapy and emphasizes the importance of endocr
ine testing of those stallions for which GnRH therapy is being contemp
lated.