Autoradiographic distribution and physiological regulation of 2-[125I]iodomelatonin binding in rat epididymis.
Autoradiographic study was conducted to localize 2-[125I]iodomelatonin binding in the rat epididymis. In the peripubertal (6 weeks old), postpubertal (8 weeks old) and adult (3 months old) rats, intense specific 2-[125I]iodomelatonin labelling of the corpus epididymidis was observed. The intensity of 2-[125I]iodomelatonin binding in the distal epididymal segment was significantly decreased in orchidectomized rats but the effect could be reversed with testosterone replacement. The intensity of 2-[125I]iodomelatonin binding in the distal rat epididymal segment did not show any diurnal rhythmicity when mid-light period and mid-dark period levels were compared, and was unaffected by constant lighting. Our data suggest androgen-dependent expression of 2-[125I]iodomelatonin binding sites, independent of light-induced changes in circulating melatonin, in the rat corpus epididymidis. A novel role of melatonin and its receptor in the regulation of the functions of rat corpus epididymidis is strongly implicated.
Shiu
S Y
SY
Department of Physiology, University of Hong Kong, Hong Kong. sywshiu@hkucc.hku.hk
Chow
P H
PH
Yu
Z H
ZH
Tang
F
F
Pang
S F
SF
D000818:Animals; D001345:Autoradiography; D002940:Circadian Rhythm; D004822:Epididymis / Q000378:metabolism*; D007457:Iodine Radioisotopes; D008027:Light; D008297:Male; D008550:Melatonin / Q000378:metabolism*; D009919:Orchiectomy; D017440:Photoperiod; D051381:Rats; D017207:Rats, Sprague-Dawley; D014018:Tissue Distribution
D007457:Iodine Radioisotopes; D008550:Melatonin