| Autor: |
Davis, S. L., Anfinson, M. |
| Zdroj: |
Journal of Animal Science; July 1975, Vol. 41 Issue: 1 p172-177, 6p |
| Abstrakt: |
Ten ewe lambs (approximately 40 kg) were used to determine the influence of prostaglandin E1(PGE1) and synthetic somatotropin-release inhibiting factor (SRIF) on plasma levels of ovine growth hormone (GH), prolactin (PRL) and thyrotropin (TSH). Intravenous injection of PGE1(20 and 100 µg/kg) stimulated a dose-related increase in plasma levels of GH (20 ± 6 and 50 ± 10 ng/ml), respectively. Intravenous injection of SRIF (500 µg), significantly (P<.05) depressed the GH stimulation by PGE1(20 µg/kg), while lower doses (5 and 50 µg) were ineffective. The highest dose of PGE1(100 µg/kg) also stimulated a significant (P<.01) increase in plasma levels of PRL. One and 10 µg doses of PGE1/kg had no influence, while the 20 µg/kg dose appeared to stimulate PRL secretion although the response was quite variable. Treatment with SRIF (500 µg) significantly (P<.05) reduced the PRL stimulation by PGE1at 20 µg/kg. However the variable PRL response to the 20 µg/kg dose of PGE1makes this observation inconclusive. Neither PGE1nor SRIF exerted an influence on plasma TSH.These data demonstrate the dose-related stimulatory effect of intravenously administered PGE1on secretion of GH and PRL. The GH response to PGE1at doses less than 100 µg/kg was more consistent than that for PRL. The observation that the stimulatory effect of PGE1on GH is partially inhibited by a single injection of 500 µg of SRIF is in support of previous reports that high doses of SRIF are inhibitory to the GH response to a variety of stimuli in other species. SRIF likely does not exert a physiological effect on the secretion of either PRL or TSH in sheep. |
| Databáze: |
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