| 研究実績の概要 |
I conducted hormonal analysis of fecal samples of Japanese macaques collected from captivity, semi-captivity and free-ranging (Jigokudani Monkey Park, Nagano). The preliminary results of captive females revealed that DHEAS increase at late pregnancy, but not when the fetus is dead. Thus, DHEAS can be a good predictor of fetal loss in Japanese macaques. Prior to cortisol and testosterone measurements, I validated both assay methods for fecal samples, physiologically by ACTH/hCG administration in captive monkeys and biologically by comparing testosterone levels between castrated and intact males. Additional analysis of testosterone and cortisol showed that behavior, environment, and age can significantly influence hormonal levels. I also found that cortisol is influenced by age, temperature, reproductive state (for females) and by the unique hot spring bathing habit of Jigokudani monkeys.
Furthermore, I conducted biological validation of a cortisol assay of orangutan feces. We observed a peak in cortisol levels one day after a stressful procedure, the anesthetizing and blood sampling of a female orangutan from Orang-Utan Island in Bukit Merah, Malaysia. Further analysis of fecal samples from wild orangutans showed cortisol changes in a juvenile female that was stuck in a tree and had to be rescued, treated in a rehabilitation center, and then released back to the forest.
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| 今後の研究の推進方策 |
I am currently analyzing housing condition effect on cortisol by comparing fecal samples from captive, semi-captive and wild orangutans. For the next fiscal year I plan to validate a cheaper assay for measurement of DHEAS in orangutans and investigate the possible occurrence of adrenarche in this species, an endocrinological event believed to be shared only among humans and great apes.
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