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Accession number;04A0022321
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| Title;Studies on the Relationship between Growth Hormone and Insulin-like Growth Factor-I Secretions and Reproductive Characteristic in Ruminants-Effects of insulin-like growth factor-I on the secretion of luteinizing hormone- |
| Author;
HASHIZUME TSUTOMU
(Iwate Univ., Faculty of Agriculture, JPN)
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Journal Title;Shokuniku ni kansuru Josei Kenkyu Chosa Seika Hokokusho
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Journal Code:X0296A
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ISSN:
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VOL.21;NO.;PAGE.53-56(2003)
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| Figure&Table&Reference;FIG.3, REF.13 |
| Pub. Country;Japan |
| Language;Japanese |
| Abstract;The role of insulin-like growth factor I(IGF-I) in the release of luteinizing hormone(LH) is unclear in ruminants. In the present study, the effects of IGF-I on the release of LH stimulated by gonadotropin-releasing hormone(GnRH) were examined in primary cultures of bovine anterior pituitary cells, and the interaction between estradiol-17.BETA.(E2) and IGF-I was characterized. GnRH(100nM)-stimulated LH release from the cultured cells was increased(P<0.05) 12, 24 and 36h after addition of IGF-I(250ng/ml), with a maximum at 12h. IGF-I at concentrations of 25, 250 and 500ng/ml increased the release of LH(P<0.05), when compared with controls. E2(10nM), IGF-I(250ng/ml) and combined treatment of E2 plus IGF-I also induced significant increases in LH release(P<0.05). The amounts of LH release after treatment with E2 alone was greater than with IGF-I alone(P<0.05). When E2 and IGF-I were added together, the release of LH was significantly greater than with either E2 alone or IGF-I alone(P<0.05). These results show that IGF-I enhances GnRH-stimulated LH release and IGF-I interacts with E2 to increase the response to GnRH in cattle. (author abst.) |
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