Annual changes in levels of plasma LH and size of cloacal protrusion in Japanese quail (Coturnix coturnix japonica) housed in outdoor cages under natural conditions.
Japanese quail of the strain used in our laboratory do not show a complete decrease in levels of circulating luteinizing hormone (LH) concentrations and show no collapse of the testes following their transfer from long to short days under laboratory conditions. Thus, merely manipulating photoperiods in the laboratory does not simulate an annual breeding cycle. To see whether an annual breeding cycle does exist in "our" quail under natural conditions, mature male birds were housed in individual cages and placed on the roof of a building at 35 degrees 45'N, 139 degrees 53'E; day length and ambient temperature were not controlled at all though food and water were continuously supplied. For 16 months blood was collected every week and the area of the cloacal protrusion measured at the time of each blood collection. The results showed that levels of plasma LH and the area of the cloacal protrusion had a clear annual cycle under the natural conditions. To detect more precisely the changes in circulating LH concentrations during spring and autumn, samples were collected every other day. The first significant increase in levels of plasma LH was found when the day length exceeded 12-12.5 hr, though the increase was sporadic and not synchronized among individuals. The results also showed that circulating levels of LH declined significantly in early September starting when the day length was still about 14 hr; this downward trend continued rather steadily to nonbreeding levels.(ABSTRACT TRUNCATED AT 250 WORDS)
Wada
M
M
Department of General Education, Tokyo Medical and Dental University, Chiba, Japan.
Akimoto
R
R
Tsuyoshi
H
H
D000704:Analysis of Variance; D000818:Animals; D002988:Cloaca / Q000033:anatomy & histology*; D003080:Cold Temperature; D003370:Coturnix / Q000502:physiology*; D008027:Light; D007986:Luteinizing Hormone / Q000097:blood*; D008297:Male; D010507:Periodicity
D007986:Luteinizing Hormone