title: Serum leptin concentrations in Lipizzan fillies.
abstract: To determine seasonal changes in circulating leptin concentrations, as well as leptin fluctuations in various patterns of seasonal ovarian activity, blood samples were taken in 107 Lipizzan fillies aged 1-4 years over the whole year from January to December. Serum concentrations were measured in samples obtained once a month (leptin) or twice a month (progesterone), and evaluated with respect to the age of animals (yearlings, 2-, 3- and 4-year olds) and the pattern of ovarian activity (anoestrous, seasonal cycle, prolonged cyclicity, continuous cyclicity). The mean and monthly leptin concentrations in 3- and 4-year olds were significantly higher than in yearlings and 2-year olds (p < 0.001). Circulating leptin levels in 3- and 4-year olds increased significantly in summer, to peak in August and then decline significantly (p < 0.001) in autumn. The fluctuations in younger fillies were less evident. The highest mean serum leptin concentrations were observed in fillies exhibiting continuous cyclicity and the lowest in those, exhibiting seasonal cyclicity (p < 0.001). In anoestrous fillies, leptin concentrations were lower than in fillies with prolonged or continuous cyclicity but higher than in fillies with seasonal cyclic activity (p > 0.05).
authors.affiliation: Institute of Physiology, Pharmacology and Toxicology, Veterinary Faculty, University of Ljubljana, Ljubljana, Slovenia. nina.cebulj@vf.uni-lj.si
authors.forename: N
authors.initials: N
authors.lastname: Cebulj-Kadunc
authors.forename: M
authors.initials: M
authors.lastname: Kosec
authors.forename: V
authors.initials: V
authors.lastname: Cestnik
mesh_terms: D000375:Aging / Q000097:blood; D000818:Animals; D001947:Breeding; D030762:Estrous Cycle / Q000097:blood*; D005260:Female; D006736:Horses / Q000097:blood*; D020738:Leptin / Q000097:blood*; D011374:Progesterone / Q000097:blood; D012621:Seasons
chemical_list: D020738:Leptin; D011374:Progesterone