SIMULTANEOUS QUANTIFICATION OF PROGESTERONE, ESTRONE, ESTRADIOL-17-BETA AND CORTICOSTERONE IN FEMALE AMERICAN KESTREL PLASMA

Progesterone, estrone, estradiol-17.beta. and corticosterone were quantified simultaneously for the 1st time in female American kestrel (F. sparverius) plasma. A mean level for each hormone was determined for the laying and non-laying periods of the summer (April-Sept.), and for Feb. Means were comparable to those of other wild avian species and were significantly higher for the laying period than for the other 2 periods. The mean corticosterone level for Feb. was higher than that for the non-laying summer period. Plasma from laying kestrels, unlike that from other avian species, required lipid removal before column chromatography. Of 2 lipid removal techniques compared, i.e., the cold methanol and hexane:methanol techniques, the latter proved superior.