title: Seasonal variations in reproductive hormones in free-ranging echidnas (Tachyglossus aculeatus): interaction between reproduction and hibernation.
abstract: We measured the reproductive steroids testosterone and progesterone in free-ranging adult echidnas over several years. For months other than June-August, the mean progesterone concentration was 0.18+/-0.12 ng ml(-1) (n=14), and all blood samples taken from active female echidnas in June-August had progesterone concentrations above 0.5 ng ml(-1). The highest progesterone value measured was 13.4 ng ml(-1) in a pregnant female several days before egg-laying. For months other than June-August the mean testosterone concentration was 0.09+/-0.05 ng ml(-1) (n=13). During June-August all active sexually mature males had testosterone concentrations in excess of 0.2 ng ml(-1) and were found in mating groups at some time during this period. The highest plasma testosterone concentration measured was 4.62 ng ml(-1).
authors.affiliation: Discipline of Anatomy and Physiology, University of Tasmania, Hobart, Tasmania, Australia. s.c.nicol@utas.edu.au
authors.forename: Stewart
authors.initials: S
authors.lastname: Nicol
authors.forename: Niels A
authors.initials: NA
authors.lastname: Andersen
authors.forename: Susan M
authors.initials: SM
authors.lastname: Jones
mesh_terms: D000818:Animals; D005260:Female; D006605:Hibernation / Q000502:physiology*; D008297:Male; D011247:Pregnancy; D011374:Progesterone / Q000097:blood*; D012098:Reproduction / Q000502:physiology*; D012621:Seasons; D004442:Tachyglossidae / Q000502:physiology*; D013739:Testosterone / Q000097:blood*
chemical_list: D013739:Testosterone; D011374:Progesterone