| Budget Amount *help |
¥5,330,000 (Direct Cost: ¥4,100,000、Indirect Cost: ¥1,230,000)
Fiscal Year 2013: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2012: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2011: ¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000)
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| Research Abstract |
Since hagfishes are considered the most primitive vertebrate known, living or extinct, studies on their reproduction are important for understanding the evolutionary aspects of the vertebrate reproductive endocrine system. Recently, single functional GTH was identified in the hagfish pituitary gland. In the present study, cytochrome P450 side-chain cleavage enzyme (CYP11A) was cloned from the hagfish testis. A clear positive correlation was noted between CYP11A mRNA levels and gonadal development in both sexes. Moreover, hagfish GTH stimulated CYP11A mRNA levels in the cultured testis. A PQRFamide peptide identified from the hagfish hypothalamus was shown to stimulate GTH mRNA levels in the hagfish pituitary. The present study further showed the presence of a steroid (estradiol) feedback system at the hypothalamic-pituitary levels. It is suggested that vertebrates, during their early evolution, have established the hypothalamic-pituitary-gonadal axis.
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