Autoradiographic localization of binding sites for 2-[125I]iodomelatonin in the pars tuberalis of the western spotted skunk (Spilogale putorius latifrons).

Pineal melatonin secretion mediates photoperiodic regulation of implantation of blastocysts in the female western spotted skunk. Autoradiography studies demonstrated that high affinity 2-[125I]iodomelatonin binding sites are present in the pars tuberalis but not in any other hypophyseal region or in the hypothalamus or thalamus of this species. This restricted localization of 2-[125I]iodomelatonin binding, which was characteristic of spotted skunks sacrificed at various times during their annual reproductive cycles, suggests that the pars tuberalis mediates photoperiodic responses in this species.