Abstract |
Although studies have indicated that follicle-stimulating hormone (FSH) and luteinizing hormone (LH) release can be dissociated in the pig, the underlying mechanisms are still to be answered. Since it was demonstrated that lamprey gonadotropin-releasing hormone (l- GnRH-III) has preferential FSH-releasing potency in several mammalian species, we have investigated the gonadotropin-releasing activity of l- GnRH-III in barrows. Each of nine barrows ( body weight: 85-90 kg; age: 207 days) received 2 ml saline (S-barrow), followed by 150 microg l- GnRH-III (1.6-1.7 microg/kg body weight) dissolved in 2 ml saline intramuscularly 7 days later. Three pre-treatment and 13 post-treatment blood samples were taken at intervals of 30 min to 8 h to assess basal and treatment-associated concentrations of FSH and LH, respectively, by radioimmunoassay. Animals were defined as having responded to treatment if, 2 h post-treatment, plasma FSH and/or LH levels were >3 SD of the respective basal concentrations. There was no treatment-associated FSH response after saline treatment, but a clear FSH response in all l- GnRH-III-injected barrows. On average, the maximum FSH level (205% of the basal concentration) was observed at 1 h post-treatment. Mean FSH values were elevated until 10 h post-treatment. There was no LH response either to saline or to l- GnRH-III. In conclusion, this study demonstrates a selective FSH-releasing activity of 150 microg l- GnRH-III in barrows. Further studies are needed to investigate whether this effect is ubiquitous in the pig and what the physiological relevance is.
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Authors | J Kauffold, F Schneider, W Zaremba, K-P Brüssow |
Journal | Reproduction in domestic animals = Zuchthygiene
(Reprod Domest Anim)
Vol. 40
Issue 5
Pg. 475-9
(Oct 2005)
ISSN: 0936-6768 [Print] Germany |
PMID | 16149955
(Publication Type: Journal Article)
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Chemical References |
- Oligopeptides
- gonadotropin-releasing hormone-III
- Gonadotropin-Releasing Hormone
- Luteinizing Hormone
- Follicle Stimulating Hormone
- Pyrrolidonecarboxylic Acid
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Topics |
- Animals
- Area Under Curve
- Follicle Stimulating Hormone
(metabolism)
- Gonadotropin-Releasing Hormone
(administration & dosage, pharmacology)
- Injections, Intramuscular
(veterinary)
- Kinetics
- Lampreys
- Luteinizing Hormone
(drug effects, metabolism)
- Male
- Oligopeptides
(administration & dosage, pharmacology)
- Pyrrolidonecarboxylic Acid
(administration & dosage, analogs & derivatives, pharmacology)
- Radioimmunoassay
(methods, veterinary)
- Swine
(physiology)
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