Expression of Steroid Hormone Receptors in the Genital Structures of a True Hermaphrodite Pug Dog

Hermaphroditism is a rare and a not well‐understood disordered sexual development (DSD) in dogs. The objective of the study was to analyse the sex steroid hormone receptor (STHR) expression patterns in the internal genital structures, because the responsiveness of the different tissue types to the steroid hormones may have a key role in pathological alterations based on DSDs. Furthermore, the adhesion molecule β‐catenin was investigated by means of immunohistochemistry because of its important role in development, tissue integrity and disease. Molecular sexing was performed via PCR targeting DBX/DBY genes to identify the pug dog as a true XX hermaphrodite. The portions of uterine tissue revealed comparable expression patterns for STHRs as investigated in normal female reproductive tissue. In the male parts, β‐catenin showed strong expression in the Sertoli cells of the seminiferous tubules; this was in contrast to normal testicular tissue. Likewise, the layers of smooth muscle actin‐positive cells surrounding the seminiferous tubules were reduced in the hermaphrodite. The results of this study deepen the knowledge of tissue characteristics in a hermaphrodite dog and highlight the importance of early diagnosis because the STH responsiveness in maldeveloped reproductive tissue might lead to serious problems for the dog.