The development of the prostate and the normal descent of the testes in the tammar wallaby (Macropus eugenii) were influenced by treatment with the non-steroidal anti-androgen flutamide. Male pouch young were treated daily from day 9 to day 45, or from day 20 to day 45, of pouch life. Prostate development was inhibited in both treatment groups to a similar extent. Since prostatic buds do not form until day 25 of pouch life, these results suggest that there is a window of androgen sensitivity operating between day 20 and day 25 of pouch life. The number of prostatic buds was significantly lower, but despite the duration of treatment there was never complete abolition of prostate development. Although testes had descended to the same position in treated and control pouch young, inguinal hernias developed in three of four animals treated with flutamide from day 9. These data demonstrate that virilization of the male reproductive tract in this marsupial is dependent on a relatively brief exposure to androgens. Blocking androgen receptor action interferes with normal development of the inguinal canal, which suggests that it is this aspect of inguinoscrotal testicular descent that is androgen dependent.
J. C. Lucas, M. B. Renfree, G. Shaw, and C. M. Butler
S. K. Wasser, R. Thomas, P. P. Nair, C. Guidry, J. Southers, J. Lucas, D. E. Wildt, and S. L. Monfort
A study was conducted in captive baboons to determine (i) the impact of cereal dietary fibre on faecal progestogen excretion, and (ii) whether means of controlling dietary effects could be identified. Blood was collected on 3 days per week and faeces on 5 days per week from four unanaesthetized cyclic female baboons, consecutively fed three diets of 5, 10 and 20% fibre for 90 days per diet. A 2 day lag time was detected before progesterone in the blood appeared in the faeces, regardless of diet (mean correlation was 0.62, P = 0.002). Increased dietary fibre had a negative effect on progestogen excretion (P < 0.004). Correspondence between blood and faecal progestogens was consistently greatest and the effect of dietary fibre least when faecal progestogens were expressed g−1 dry faeces. Several means of indexing faecal steroid excretion rates were examined including dehydroepiandrosterone (DHEA) and a number of byproducts of cholesterol metabolism. The cholesterol metabolite, cholestanone, was positively correlated with dietary fibre (r = 0.27; P < 0.04). Multiplying faecal progestogen concentration by the cholestanone g−1 dry faeces concentration increased the correlation between serum and cholestanone-indexed faecal progestogens (r = 0.78, P = 0.0001) compared with nonindexed progestogens (r = 0.71, P = 0.0001). We conclude that expressing faecal progestogens g−1 dry faeces may be sufficient and the most cost-effective method for controlling for most dietary effects when the objective is monitoring longitudinal endocrine status in baboons. However, it may be appropriate to express faecal progestogens by cholestanone concentrations when increased precision is needed to overcome the effects of profound variations in dietary fibre.