| 研究実績の概要 |
I developed a new Enzyme Immunoassay (EIA) to detect dehydroepiandrosterone-sulfate (DHEAS) levels in feces of Japanese macaques and orangutans collected in the previous year. I validated the assay by confirming that DHEAS levels increased after DHEA challenge in one male and one female Japanese macaques. Additional challenges using Adrenocorticotrophic hormone (ACTH) and human chorionic gonadotropin(hGC) in other monkeys revealed that the intra-muscular injection of ACTH and hCG did not stimulate the adrenal to secrete DHEAS in Japanese macaques. The study has been published at the International Journal of Primatology. I also published the results from the previous year in the journla Primates, related to the stress-reducing effect of hot springs in stress levels of Japanese macaques.
Another part of this project included the validation of the EIA for measurement of DHEAS in feces of orangutans. I investigated hormonal changes (DHEAS and glucocorticoids) levels with: (a) stress response, (b) reproductive state, and (c) age in orangutans from captivity and from the wild. The results suggest that DHEAS rises in response to increase in GC levels. I also found that pregnant females had the highest levels of DHEAS, and that early lactating females had the highest levels of fGC. Finally, I found that DHEAS is lower in infants than in adults and adolescents, with a pre-pubertal increase on DHEAS levels. This phenomenon is called adrenarche, and it is present in humans, chimpanzees, and bonobos, but not in macaques and lower primates.
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