Papers
More filters
Journal Article•
TL;DR: Cloacal gland (an androgen dependent sex accessory) of Japanese quail exhibits full breeding condition as long as these were maintained under long days (LD 16:8), but, when the birds were shifted to 13L, photoresponses cannot be generalized and it depends on the photoperiod to which quail were exposed previously.
Abstract: Cloacal gland (an androgen dependent sex accessory) of Japanese quail exhibits full breeding condition as long as these were maintained under long days (LD 16:8). When shifted to short daylength (LD 6:18), scotosensitivity (cloacal gland regression) was observed up to 5 weeks, followed by scotorefractoriness (cloacal gland development). There was a regression in cloacal gland volume of the birds when shifted to intermediate daylength (LD 13.5:10.5 and 13:11) after 12 weeks of exposure to long days (relative refractoriness) but no regression when shifted to relatively short days (< 14 hr) after 3 weeks of exposure to long daylength. Birds maintained under constant short photoperiod (LD 6:18) exhibited cyclicity. Shift experiments (quail reared and maintained under continuous light; LL, were shifted to LD 16:8, 13:11 and 8:16, similarly quail maintained under LD 16:8 were shifted to rest three photoperiods and so on) made to compare the cloacal gland responses indicated that if the difference between two photoperiods (previous and shifted one) was more the percentage of difference in cloacal gland response was also high. Short daylength (LD 8:16) was always gonadoinhibitory for the quail previously exposed to any daylength (13L, 16L or 24L) and 16L and 24L were always stimulatory for the quail previously exposed to other daylength (8L, 13L, 16L). But, when the birds were shifted to 13L, photoresponses cannot be generalized and it depends on the photoperiod to which quail were exposed previously (i.e. photoperiodic history).
51 citations
Journal Article•
13 citations
TL;DR: A study of the temporal synergism of serotonergic and dopaminergic activity in the regulation of reproductive seasonality of photosensitive and photorefractory migratory Red headed bunting found that full gonadal growth was achieved much in advance to that of control birds.
Abstract: A study of the temporal synergism of serotonergic and dopaminergic activity in the regulation of reproductive seasonality of photosensitive and photorefractory migratory Red headed bunting was undertaken. In experiment 1, groups of birds kept in natural day length (NDL) in their photosensitive phase (April) received daily injections of L‐DOPA (L‐dihydroxyphenylalanine, a dopamine precursor) at 8 and 12 hr after 5‐HTP (5 hydroxytryptophan, a serotonin precursor) administration. One control group received two daily injections of saline. The injections with 12‐hr temporal relation induced early recrudescence and full gonadal growth was achieved much in advance to that of control birds. The applications with 8‐hr temporal relation suppressed the testicular growth initially but later on this effect was eliminated by NDL of May‐June. In Experiment 2, photorefractory birds also received the treatments but the temporal relation of 5‐HTP and L‐DOPA had no effect on the regressed gonads of these birds. Thi...
7 citations
Cited by
More filters
TL;DR: It is concluded that selection for reduced adrenocortical responsiveness in Coturnix is associated with acceleration in the onset of puberty in males.
51 citations
TL;DR: The results suggest that selection for reduced adrenocortical responsiveness in Coturnix is accompanied by an accelerated onset of puberty in males, and enhanced reproductive development in LS males remains extant throughout early to middle-age adulthood.
48 citations
Journal Article•
TL;DR: This article summarizes present knowledge concerning perception and transduction of light into the biological signal, model of the avian photoperiodic response, and seasonal changes in hypothalamic secretion of gonadotropin-releasing hormone, vasoactive intestinal polipeptide, as well as the gonadotropic hormone inhibitory hormone.
45 citations
TL;DR: The results suggest that selection for reduced adrenocortical responsiveness in Coturnix has resulted in certain reproductive advantages in middle-aged, adult males maintained on stimulatory photoperiods as well as in such adults subjected to photocastration and subsequent rephotostimulation.
28 citations
TL;DR: Male quail selected for reduced (low stress, LS) rather than exaggerated plasma corticosterone stress response show more photo-induced reproductive development, greater resistance to reproductive declines induced by exposure to very short days, and a quicker recovery to a higher reproductive level upon return to long days.
23 citations