title: Seasonal changes in the concentrations of plasma luteinizing hormone and testosterone in willow ptarmigan (Lagopus lagopus lagopus) with observations on the effects of permanent short days.
mesh_terms: D000818:Animals; D001683:Biological Clocks; D001717:Birds / Q000097:blood / Q000502:physiology*; D001947:Breeding; D003129:Comb and Wattles / Q000033:anatomy & histology; D008027:Light; D007986:Luteinizing Hormone / Q000097:blood*; D008297:Male; D011863:Radioimmunoassay; D012621:Seasons; D013739:Testosterone / Q000097:blood*; D013997:Time Factors
chemical_list: D013739:Testosterone; D007986:Luteinizing Hormone