Effects of oestrogen treatment on testicular descent, inguinal closure and prostatic development in a male marsupial, Macropus eugenii.
This study reports the effect of oestrogen treatment on the development of the genital ducts, prostate gland, testicular descent and inguinal canal closure in male tammar wallaby young treated with oestrogen over four time spans during the first 25 days of pouch life (days 0-10, 10-15, 15-25 and 0-25) and sampled at day 50. In control males, the Müllerian ducts had regressed and the Wolffian ducts had developed into the vas deferens and epididymis. The prostate gland had formed epithelial buds extending from the ventral, lateral and posterior walls of the urethra. The testes were in the neck of the scrotum and the gubernaculum and processus vaginalis were present at the base of the scrotum. In most males treated with oestradiol from day 0 to day 25, the testes had failed to descend by day 50. The gubernaculae were long and thin. The retained Müllerian ducts formed a lateral vaginal expansion like that of normal day 50 females. The Wolffian ducts of the males treated on days 0-25 were regressed, but were present in males in the other three treatment groups. The prostate glands were hyperplastic and epithelial budding was highly invasive. Some treated males from the day 10-25 and 0-25 groups had inguinal hernias. These results demonstrate that oestrogen treatment has profound effects on the development of the internal genitalia of a male marsupial, preventing inguinal closure and interfering with testicular descent. Therefore, the tammar wallaby may provide a useful experimental model animal in which to investigate the hormonal control of testicular migration and closure of the inguinal canal.
Coveney
D
D
Department of Zoology, The University of Melbourne, Victoria 3010, Australia. d.coveney@zoology.unimelb.edu.au
Shaw
G
G
Renfree
M B
MB
D000818:Animals; D005314:Embryonic and Fetal Development / Q000187:drug effects*; D004958:Estradiol / Q000494:pharmacology*; D005837:Genitalia, Male / Q000187:drug effects* / Q000196:embryology*; D005865:Gestational Age; D006965:Hyperplasia; D007614:Macropodidae / Q000196:embryology*; D008297:Male; D023421:Models, Animal; D009095:Mullerian Ducts / Q000187:drug effects; D011467:Prostate / Q000187:drug effects / Q000196:embryology*; D013737:Testis / Q000196:embryology; D014928:Wolffian Ducts / Q000187:drug effects
D004958:Estradiol