Results from trials 1 and 2 show obvious age-related changes in LH and T that are independent of, but modified by, photoperiods. To determine whether pulsatile patterns of LH and T at different ages during growth and development are present or are modified by photoperiods, secretory patterns of LH and T were determined at 13, 23, and 35 wk of age in male turkeys exposed to lighting treatments LL and SL. The turkeys at 13 wk of age were not sexually mature, but equivalent robust pulses of LH and pulses of T were detected in the two photoperiod groups. Cheap Diskus Advair
This observation suggests that photoperiods have little influence on controlling the secretion of LH and T in the male turkeys at prepubertal or immature ages. In contrast, photoperiod does influence levels of plasma LH in starlings during pubertal development. Increases in plasma LH level were observed in starlings exposed to an SD photoperiod during development but not under an LD photoperiod from hatch, and the authors concluded that this species is photorefractory at hatch. In contrast, the present data indicate that male turkeys, similar to male chickens, are not photorefractory at hatch.