Plasma and pituitary luteinizing hormone in intact and castrated tree sparrows (Spizella arborea) during a photoinduced gonadal cycle

Wilson, Fred E.; Follett, B. K.

doi:10.1016/0016-6480(74)90056-2

Cited by 84 publications

(38 citation statements)

References 21 publications

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“…First, the finding that, in canaries on 8L/16D, ovariectomy increased plasma IR-LH and oestrogen treatment reduced it indicates the presence of active sex-steroid feedback in birds exposed to short daylengths. Similar findings have been made in male quail (B. K. Follett and B. L. Gledhill, unpublished observa¬ tions) and tree sparrows (Wilson & Follett, 1974), but its physiological import¬ ance is unknown. Such feedback is absent in photorefractory birds (Table 9).…”

Section: Discussionsupporting

confidence: 80%

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Effect of Photoperiod on Oestrogeninduced Nest-Building in Ovariectomized or Refractory Female Canaries (Serinus Canarius)

Hinde¹,

Steel²,

Follett³

1974

Reproduction

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Nest building was induced in ovariectomized photosensitive canaries with a standard dose of oestradiol (0\m=.\05mg thrice weekly) at various times of year. On a range of daylengths between 6 and 18 hr light/day, building behaviour tended to be more intense if the birds were exposed to long photoperiods. A similar result was found in photorefractory birds, both intact and ovariectomized.Differences in building were unlikely to have been due solely to the amount of time available to birds on different photoperiods as hourly building rates still revealed a difference between groups. A marked difference in the latency of the response to oestrogen was found in the refractory birds.Ovariectomy was not complete in many birds but the evidence from such birds and from the few which had been totally ovariectomized, as well as from those in the refractory period when long days did not result in ovarian growth, showed that endogenous oestrogen secretion was negligible.The effect of long photoperiods in augmenting the induction of nestbuilding by oestrogen could not be reproduced by injections of either ovine or avian LH. This and other evidence suggests that a direct effect of gonadotrophins is not involved.

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Section: Discussionsupporting

confidence: 80%

“…4 than in the 16L/8D birds suggests that the sex-steroid feedback system had been re-established in the 8L/ 16D birds. The low IR-LH levels in the ovariectomized refractory birds suggest that refractory canaries do have a much depressed level of LH secretion, a finding in keeping with data on tree sparrows (Wilson & Follett, 1974).…”

Section: Discussionsupporting

confidence: 58%

Effect of Photoperiod on Oestrogeninduced Nest-Building in Ovariectomized or Refractory Female Canaries (Serinus Canarius)

Hinde¹,

Steel²,

Follett³

1974

Reproduction

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“…Increased photoperiod stimulates both the synthesis and release of gonadotrophins and hence gonadal growth and a functionally reproductive state (quail: Nicholls et al, 1973;Follett, 1976;canary: Nicholls, 1974; white crowned sparrow: Follett et al, 1975). In some birds, after 1 to 2 months on a stimulatory long photoperiod, gonadotrophin concentrations decrease and the gonads regress (Wilson and Follett, 1974). Long photoperiods will stimulate sexual activity in these birds only after they have passed through a period of short daylengths to break the photorefractive state (Follett et al, 1975).…”

Section: Introductionmentioning

confidence: 97%

Effect of photoperiod on gonadotrophin concentrations in domestic turkeys

Godden

Scanes

1977

British Poultry Science

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1. Circulating immunoreactive luteinising hormone (LH) and follicle stimulating hormone (FSH) concentrations have been measured during photoperiodically-induced changes in the reproductive state of turkeys. 2. In a period of sexual quiescence on short photoperiods (6L: 18D) LH concentrations were higher during the hours of darkness in both sexes. 3. Transfer to long photoperiods (16L: 8D) stimulated a rapid increase in LH and FSH concentrations. This was maintained for between 2 to 3 months when the concentrations of both gonadotrophins decreased as the birds became photorefractory. 4. Return to short photoperiods had no immediate effect on the concentrations of LH and FSH in females. The concentration of LH was increased during the 3rd week of short photoperiods when the hens were moulting. 5. LH concentrations fluctuated during the ovulatory cycle and were highest about 6 h before ovulation.

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“…In animals as diverse as grouse, quail, sparrows, pony mares and rams, photic-induced changes in circulating gonadotropin levels are observed in castrated as well as intact animals (Wilson and Follett, 1974;Pelletier and Ortavant, 1975b;Gibson et al, 1975;Garcia and Ginther, 1976;Mattocks et al, 1976;Sharp and Moss, 1977). ; Interestingly, while the photoperiod can alter serum levels of LH in castrated rams (Pelletier and Ortavant, 1975b), no effect of day length is observed in ovariectomized ewes (Legan et al, 1977).…”

Section: Photic-induced Changes In the Hypothalamic-pituitary-gonadalmentioning

confidence: 99%

Photoperiodic Regulation of Neuroendocrine-Gonadal Activity

Turek

Campbell²

1979

Biology of Reproduction

224

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Plasma and pituitary luteinizing hormone in intact and castrated tree sparrows (Spizella arborea) during a photoinduced gonadal cycle

Cited by 84 publications

References 21 publications

Effect of Photoperiod on Oestrogeninduced Nest-Building in Ovariectomized or Refractory Female Canaries (Serinus Canarius)

Effect of Photoperiod on Oestrogeninduced Nest-Building in Ovariectomized or Refractory Female Canaries (Serinus Canarius)

Effect of photoperiod on gonadotrophin concentrations in domestic turkeys

Photoperiodic Regulation of Neuroendocrine-Gonadal Activity

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