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Comparative sex‐related differences of excretory sex steroids from day‐old Andean condors ( Vultur gryphus ) and peregrine falcons ( Falco peregrinus ): Non‐invasive monitoring of neonatal endocrinology
Author(s) -
Bercovitz Arden Bryan,
Sarver Patricia L.
Publication year - 1988
Publication title -
zoo biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.5
H-Index - 54
eISSN - 1098-2361
pISSN - 0733-3188
DOI - 10.1002/zoo.1430070208
Subject(s) - biology , androgen , testosterone (patch) , estrone , excretory system , endocrinology , medicine , estrogen , hormone
Sex‐related differences in excretory steroids were monitored by radioimmunoas‐say (RIA) from allantoic egg waste samples of day‐old Andean condors ( Vultur gryphus ) and peregrine falcons ( Falco peregrinus ). Total immunoreactive estrogens (E T ), estradiol isolated by chromatography (E 2C ) or by estradiol‐specific (E 2S ) antibody, estrone isolated by chromatography (E 1C ), total androgen (T T ), or chromatographed testosterone (T C ) were measured by RIA. All estrogenic concentrations were higher ( P < 0.04) in females than in males of both species. Female condor E T and E 2C levels were each fivefold greater than males; female condor E 1C data were twofold greater than in males. Female peregrine falcon E T concentrations were only 25% greater than males; female falcon E 2S data were 70% greater than in males. Excretory androgen (T T ) concentrations from condors were half as large in females ( P < 0.03) than in males; falcon T T levels were not sexually distinct ( P > 0.05). Reliable prediction of sex in both species ( P < 0.05) was accomplished by estrogen:androgen ratio evaluation, which also eliminated discrepancies in absolute hormone concentration differences between samples for each species.