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Pineal 5-methoxytryptophol rhythms in the box turtle: Effect of photoperiod and environmental temperature

1989; Elsevier BV; Volume: 98; Issue: 1 Linguagem: Inglês

10.1016/0304-3940(89)90375-3

1872-7972

Debra J. Skene, B. Vivien-Rœls, Paul Pévet,

Nitric Oxide and Endothelin Effects

The effect of different photoperiods and temperatures on pineal 5-methoxytryptophol (ML) content was investigated in male box turtles, Terrapene carolina triunguis. A rhythm in pineal ML was evident in the long photoperiod (18 h light (L)-6 h dark (D)) with high daytime levels of 178 ± 48 pg/gland (x̄ ± S.E.M.) which dropped to 38 ± 6 pg/gland during lights off. In the short photoperiod (8L:16D) no clearcut ML rhythm was observed. Diurnal (10.00–12.00 h) ML concentrations rose linearly (P < 0.05) with increasing ambient temperatures (5, 15, 20 and 27°C). Day/night differences in ML levels, however, were not significant. Pineal ML in the box turtle thus seems to be modified by the photoperiod and, to a lesser extent, by temperature.