scholarly journals Effect of an anti-androgen on testicular descent and inguinal closure in a marsupial, the tammar wallaby (Macropus eugenii)

Reproduction ◽  
2002 ◽  
pp. 865-874 ◽  
Author(s):  
D Coveney ◽  
G Shaw ◽  
JM Hutson ◽  
MB Renfree
Keyword(s):  
Dorsal Root ◽  
Inguinal Canal ◽  
Prostate Gland ◽  
Tammar Wallaby ◽  
Calcitonin Gene Related Peptide ◽  
Hormonal Control ◽  
Testicular Descent ◽  
Genitofemoral Nerve ◽  
Related Peptide ◽  
Calcitonin Gene

Androgens are essential for testicular descent in eutherian mammals, but little is known about its hormonal control in marsupials. This study reports the effects of daily treatment with the anti-androgen flutamide (10 mg kg(-1)) from day 9 to day 75 after birth on the descent of the testis and inguinal closure in tammar wallabies. By day 75 after birth, the testes of control males had descended and the prostate gland was well developed. The testes of all flutamide-treated males had passed through the inguinal canal and were situated in the base of the scrotum. Three of the nine flutamide-treated males had unilateral inguinal hernias. The size of the inguinal canal, regardless of whether a hernia was present, was significantly wider than that of control males. Development of the prostate gland was significantly inhibited. By day 75 after birth, the phallus was significantly longer in control males than in females, whereas the phallus of flutamide-treated males was similar to that of control females. In flutamide-treated males, the lumbar 1 dorsal root ganglia was feminized and significantly fewer cell bodies expressed calcitonin gene- related peptide. As the anti-androgen treatment resulted in a reduction in the number of calcitonin gene-related peptide-positive cell bodies in the dorsal root ganglion supplying the genitofemoral nerve, the process of inguinal closure in tammar wallabies may be mediated by calcitonin gene-related peptide via the genitofemoral nerve, as indicated in humans. Flutamide treatment inhibited development of the prostate gland and phallus, which are both androgen-dependent structures, but it did not affect the normal descent of the testis, indicating that testicular descent can proceed when the action of androgens is blocked.

scholarly journals Effects of oestrogen treatment on testicular descent, inguinal closure and prostatic development in a male marsupial, Macropus eugenii

Reproduction ◽  
2002 ◽  
pp. 73-83 ◽  
Author(s):  
D Coveney ◽  
G Shaw ◽  
MB Renfree
Keyword(s):  
Inguinal Canal ◽  
Prostate Gland ◽  
Tammar Wallaby ◽  
Hormonal Control ◽  
Testicular Descent ◽  
Oestrogen Treatment ◽  
Model Animal ◽  
Internal Genitalia ◽  
Mullerian Ducts ◽  
Testicular Migration

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 Mullerian 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 Mullerian 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.

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