Role of oestradiol in the regulation of the seasonal antler cycle in female reindeer, Rangifer tarandus.

摘要: Reindeer (or caribou), Rangifer tarandus, is the only extant species of deer in which females as well males normally develop antlers that are cast and regrown each year. This study investigated role ovarian oestradiol regulation seasonal antler cycle female reindeer. Ovariectomized Norwegian reindeer living outdoors northern Norway (69\s=deg\N)were treated with continuous-release subcutaneous Silastic implants containing oestradiol, maintained blood concentrations within physiological range for mating season from June to October\p=n-\ November. The treatment induced synchronized maturation rapid cleaning velvet-like skin August\p=n-\September ovariectomized reindeer, a pattern very similar observed ovary-intact controls under same conditions. removal steroid implant November caused premature casting early winter two five animals, while remainder at normal time spring; this response was seen whether animals had received one or autumn. developed by ovariectomized, oestradiol-treated were significantly heavier carried more branches than without replacement, marginally intact controls. These results support view biologically active secreted ovary reindeers induces development antlers. Oestradiol stimulates growth mineralization bone, velvet, suppresses hard endocrine control ensures antlers, function weapons, retained throughout autumn when pregnant competition between over food snow most intense; hence there reproductive advantage explain evolution females.