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Variation in hypothalamic gonadotrophin-releasing hormone content, plasma and pituitary LH, and in-vitro testosterone release in a long-distance migratory bird, the garden warbler (Sylvia borin), under constant photoperiods


, : Variation in hypothalamic gonadotrophin-releasing hormone content, plasma and pituitary LH, and in-vitro testosterone release in a long-distance migratory bird, the garden warbler (Sylvia borin), under constant photoperiods. Journal of Endocrinology 128(3): 339-345

Changes in concentrations of hypothalamic gonadotrophin-releasing hormone (GnRH), pituitary and plasma LH, testicular mass, in-vitro release of testosterone, body mass and migratory activity were measured in male garden warblers (Sylvia borin) kept from November to June under a constant photo-period of 12.8 h. Under such conditions garden warblers gradually change from the photorefractory to the photosensitive state and gonadal recrudescence then occurs. Hypothalamic GnRH content was low from December to March, but increased in April to reach the highest levels in June. The spontaneous increase in GnRH was paralleled by increases in pituitary LH content, testicular mass and in-vitro testosterone release. Body mass decreased 1 month and nocturnal activity 2 months before the spontaneous increase in GnRH. Ovine LH increased in-vitro testosterone release over basal release at all times. The results suggest that in garden warblers (1) changes in hypothalamic GnRH content can occur under constant photoperiodic condition, (2) the gradual change from the photorefractory to the photosensitive state is not characterized by a gradual increase in hypothalamic content of GnRH (cf. starlings), and (3) Leydig cells are capable of testosterone release even during the photorefractory state.

US$19.90

PMID: 2013742

DOI: 10.1677/joe.0.1280339


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Riget, F.; Vorkamp, K.; Dietz, R.; Rastogi, S., C., 2000: Temporal trend studies on polybrominated diphenyl ethers PBDEs and polychlorinated biphenyls PCBs in ringed seals from East Greenland. The concentrations of polybrominated diphenyl ethers ( PBDEs) 17, 28, 47, 49, 66, 85, 99, 100, 153, 154, and 183 were determined in ringed seal blubber from central East Greenland collected in 1986, 1994, 1999 and during the period 2001 to 2004....

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Ornhagen, H.C., 1979: Influence of nitrous oxide, nitrogen, neon, and helium on the beating frequency of the mouse sinus node at high pressure. The beating frequency (BF) reducing effect of 150 atm of hydrostatic pressure on mammalian cardiac pacemaker tissue (hyperbaric bradycardia) was counteracted by dissolved gas only if the gas was added after hydrostatic compression. The effect on B...

Pasonen, S.; Tammi, R.; Suhonen, M.; Kirjavainen, M.; Suihko, E.; Urtti, A.; Tammi, M., 2000: A continuous rat keratinocyte cell line produces epidermal equivalent cultures for transepidermal penetration studies. Journal of Investigative Dermatology 114(4): 813, April

Yang, G.C.C.; Huang, S-Chih.; Wang, C-Lung.; Jen, Y-Sheng., 2016: Degradation of phthalate esters and acetaminophen in river sediments using the electrokinetic process integrated with a novel Fenton-like process catalyzed by nanoscale schwertmannite. The main objective of this study was to develop and establish an in situ remediation technology coupling nano-schwertmannite/H2O2 process and electrokinetic (EK) process for the removal of phthalates (PAEs) and acetaminophen in river sediments. Te...

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Dashkevich, M.S., 1954: Accessory maxillary sinuses. Vestnik Otorinolaringologii 16(4): 50-54

Tang, H.; Cuevas, H.E.; Das, S.; Sezen, U.U.; Zhou, C.; Guo, H.; Goff, V.H.; Ge, Z.; Clemente, T.E.; Paterson, A.H., 2013: Seed shattering in a wild sorghum is conferred by a locus unrelated to domestication. Suppression of seed shattering was a key step during crop domestication that we have previously suggested to be convergent among independent cereal lineages. Positional, association, expression, and mutant complementation data all implicate a WRKY...

Quick Jeffrey C., 2000: Carbon emissions from coal combustion; variation with coal rank, type and grade. Using ASTM rank parameters (1990 vintage), carbon emissions per net unit of energy are estimated for coals from 88 large western U. S. mines; the results show a 15 percent range of variation. The relationship between carbon emissions and coal rank...

Cannizzo, C.J., 1977: What have been the recent development and trends in the law of "informed consent"?. Hospital Forum 20(3): 19, 30-19, 30