Abstract
Summary
Injections of arachidonic acid directly into the corpora lutea of normal cattle at the 12th or 13th day of the estrous cycle resulted in (a) a decline in jugular vein plasma progesterone levels from an average of 6 ng/ml to 2.5 ng/ml (P < 0.05), (b) an immediate rise in PGF levels in ovarian venous plasma, and (c) a sharp rise in jugular vein plasma estrogen levels. Jugular plasma estrogen peaks were associated with each ovarian vein PGF peak in each animal; jugular plasma LH levels did not change. These results show that the bovine ovary can convert arachidonic acid to PGF and that arachidonic acid administered directly into the corpus luteum results in partial regression of the corpus luteum. PGF appears to stimulate estrogen production by the ovary in the absence of measurable changes of plasma LH.
The technical assistance of R. Saatman and Denise Lensing is gratefully acknowledged.
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