Enhancement of Effect of Chorionic Gonadotrophin on Ovarian Hyperemia in the Rat by Pituitary Extract

Abstract

The earliest demonstrable effect of chorionic gonadotrophin on the ovary of rats is the appearance of hyperemia. This reaction has been used with varying degrees of success for the rapid diagnosis of pregnancy. Attempts to enhance the effect of chorionic gonadotrophin on ovarian hyperemia led to our present use of a pituitary extract for this purpose. This was based on the well-known synergistic effect of certain anterior pituitary extracts in augmenting the ovarian response when used in conjunction with chorionic gonadotrophin. The effective component of such pituitary extracts is not known. The earlier claims that such “synergists” represent a distinct gonadotrophin no longer seems likely in view of later work indicating that similar effects can be obtained with follicle-stimulating gonadotrophins (F.S.H.). The pituitary synergist employed in these studies is reported to be chiefly F.S.H., with traces of luteinizing principle. Prolactin was not demonstrable. Methods and Results. The 28- to 32-day-old, 50 to 60 g immature albino female rats used were of a mixed strain of unknown identity. Chorionic gonadotrophin, the pituitary synergist, or their combination was injected intraperitoneally into a total of 307 rats. The rats were asphyxiated with ether and autopsied after one, 1 1/4 or 2 hours. The reaction was considered positive if one or both ovaries were light to dark crimson, and negative if both were pale or pinkish. The details of the technic used have been described by Kupperman and Greenblatt. The results are given in Table I. There were no positive reactions with the synergist alone. Chorionic gonadotrophin in a dosage of 0.6 I.U. produced positive reactions in 76% of 25 rats.