ARE RESULTS OF GONADOTROPIC ASSAY PERFORMED ON THE INTACT IMMATURE RAT VALID?

Abstract

Investigation was made to determine whether a valid test for gonadotrophic factors can be obtained by using non-hypophysectomized rats, or whether the estrogen secreted by the intact rodent disturbs the result by inducing luteini-zation through mobilization of the luteinizing factor of its own hypophysis. In a preliminary group injected solely with equivalents of 40 cc. of gonadotrophic urine, 12% showed luteinization. A primed group which received ascending doses of estrogen 48 hrs. before the gonadotrophic injs. showed increased luteinization with doses of 1.0 to 1.5 R.U., decrease above this dosage. Finally a simultaneous group (estrogen and gonadotrophic hormone injected simultaneously) showed 16.6% luteinization, an increase which did not significantly ''influence the result. The results obtained on the intact rat were apparently valid.