Effects of melatonin and 6-methoxybenzoxazolinone on photoperiodic control of testis size in adult male golden hamsters.
Consumption of young plants containing 6-methoxybenzoxazolinone (6-MBOA) appears to play an important role in the initiation of reproduction each spring in wild populations of the montane vole. Following its identification, 6-MBOA has been found to stimulate the reproductive system in a number of rodent species, but the mechanism of action remains unknown. The chemical structure of 6-MBOA is similar to melatonin, which, in addition to its well-known antigonadal effects, can exert a progonadal influence under certain experimental conditions. To determine if 6-MBOA might act as a melatonin agonist, four experiments were conducted to compare the effect of these two compounds on testis size in the golden hamster, a rodent whose responses to melatonin are well characterized. 1) Hamsters exposed to 14 h light per day (14L:10D) received a daily injection of melatonin (25.0 micrograms) or 6-MBOA (17.8 micrograms). 2) Hamsters exposed to 6L:18D received Silastic capsules (50 or 200 mm) containing melatonin or 6-MBOA. 3) Hamsters exposed to 6L:18D received chow containing melatonin (21.1 or 42.2 micrograms/gm chow) or 6-MBOA (15.0 or 30.0 micrograms/gm). 4) Hamsters exposed to 6L:18D received drinking water containing melatonin (15.5 micrograms/ml) or 6-MBOA (11.0 micrograms/ml). Testis widths were determined at 2--3 week intervals, and after 66-73 days testes were removed and weighed. Melatonin significantly influenced testis size in each experiment, but treatment with 6-MBOA had no effect in any of these experimental paradigms, indicating that 6-MBOA does not act as a melatonin agonist in the hamster. However, these results indicate that the consumption of melatonin (and presumably melatonin agonists) could serve as an environmental stimulus for reproductive activity.
Anderson
K D
KD
Department of Neurobiology and Physiology, Northwestern University, Evanston, Illinois 60201.
Nachman
R J
RJ
Turek
F W
FW
D000818:Animals; D001583:Benzoxazoles / Q000008:administration & dosage / Q000494:pharmacology*; D006224:Cricetinae; D008027:Light; D008297:Male; D008550:Melatonin / Q000008:administration & dosage / Q000502:physiology*; D008647:Mesocricetus; D013737:Testis / Q000187:drug effects* / Q000254:growth & development
D001583:Benzoxazoles; C031896:6-methoxybenzoxazolinone; D008550:Melatonin