Characterization of 2-[125I]iodomelatonin-binding sites in quail testes at mid-light and mid-dark.
The binding and pharmacological characteristics of 2-[125I]iodomelatonin binding sites in testis membrane preparations of quails were examined. Scatchard analyses yielded an equilibrium dissociation constant (Kd) of 46.6 +/- 8.6 pmol/l and maximum binding capacity (Bmax) of 2.77 +/- 0.20 fmol/mg protein for the gonadal 2-[125I]iodomelatonin binding sites. Except for melatonin, 6-chloromelatonin, 2-iodomelatonin and N-acetylserotonin, all compounds tested elicited no significant inhibition of radioligand binding. Significant diurnal variations were detected in serum melatonin levels of 24-week-old quails while no diurnal difference was detected in the affinities or densities of the gonadal 2-[125I]iodomelatonin binding sites in quails. Results of the present study suggest possible direct gonadal action by pineal melatonin in birds.
Wang
Z P
ZP
Neuroendocrinology Research Section, Clarke Institute of Psychiatry, Toronto, Ont., Canada.
Cheng
K M
KM
Brown
G M
GM
Pang
C S
CS
Pang
S F
SF
D000818:Animals; D003370:Coturnix / Q000378:metabolism*; D003624:Darkness; D007700:Kinetics; D008027:Light; D008297:Male; D008550:Melatonin / Q000031:analogs & derivatives* / Q000097:blood / Q000378:metabolism; D044094:Receptors, Melatonin; D017981:Receptors, Neurotransmitter / Q000378:metabolism* / Q000502:physiology; D013737:Testis / Q000033:anatomy & histology / Q000378:metabolism* / Q000502:physiology
D044094:Receptors, Melatonin; D017981:Receptors, Neurotransmitter; C044556:2-iodomelatonin; D008550:Melatonin