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Lamprey GnRH‐III Stimulates FSH Secretion in Barrows
Author(s) -
Kauffold J,
Schneider F,
Zaremba W,
Brüssow KP
Publication year - 2005
Publication title -
reproduction in domestic animals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.546
H-Index - 66
eISSN - 1439-0531
pISSN - 0936-6768
DOI - 10.1111/j.1439-0531.2005.00609.x
Subject(s) - endocrinology , saline , medicine , follicle stimulating hormone , luteinizing hormone , basal (medicine) , gonadotropin , radioimmunoassay , hormone , gonadotropin releasing hormone , biology , chemistry , insulin
Contents 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 μ g l‐GnRH‐III (1.6–1.7 μ g/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 μ g 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.