An Ovarian Ascorbic Acid Depleting Factor in the Plasma of Adenohypophysectomized Cockerels

Abstract

A study was made of LH levels in plasma of adenohypophysectomized cockerels, using the ovarian ascorbic acid depletion (OAAD) assay. Validity of using the OAAD assay for cockerel plasma was examined. Although OAAD activity fell during 3-14 days following surgery, there was a significant rise in activity 25 days after surgery. This level of OAAD activity was maintained at least up to 47 weeks post surgery. The OAAD factor had no LH-like effect upon the animal itself, and attempts to identify the factor as LH, by use of alternate gonadotropin assays, were not successful. A dose-response curve based on adenohypophysectomized cockerel plasma did not deviate from parallelism with the LH standard curve. While an assay of an acetoneprecipitated extract of adenohypophysectomized cockerel plasma was negative, OAAD assay of plasma filtered through a Sephadex G-100 column demonstrated 2 active fractions, one of which was identical with a fraction associated with pituitary LH from human, bovine, ovine and porcine sources. Synthetic arginine vasotocin had OAAD activity and it was conjectured that the depleting factor was associated with increased secretion of the neurophyophysis. (Endocrinology77: 651, 1965)