SELECTIVE NEUTRALIZATION OF THE FOLLICLESTIMULATING ACTION OF GONADOTROPIC PREPARATIONS BY ANTIGONADOTROPIC SERA1

Abstract

The serum of rabbits repeatedly injected with a follicle-stimulating hormone (FSH) prep. made by tryptic digestion of an aq. extract of sheep pituitary powder, selectively neutralized the follicle stimulating activity of gonadotrophic extracts. The antifollicle stimulating (anti-FSH) activity of the serum was demonstrated by its ability to inhibit the gonad stimulating action of sheep pituitary glands (SAP), pregnant mare serum (PMS) and FSH when the extract and the anti-FSH serum were administered by separate injs. to immature [female] rats. The absence of antiluteinizing properties in the serum was shown by the inability of the serum to prevent the increase in size of the seminal vesicles and prostate when injected with luteinizing hormone into immature [male] rats. The anti- FSH specificity of the serum was demonstrated by its power to neutralize selectively the follicle stimulating component of gonadotrophic extracts of SAP and PMS when the serum and the extract were simultaneously administered to immature [male] rats. The luteinizing activity of these extracts, as detd. by the response of the seminal vesicles and prostate, was not inhibited by the anti-FSH serum. The serum from rabbits which received an unfractionated extract of sheep pituitary glands inhibited the gonadotrophic action of luteinizing hormone, SAP and PMS in both immature c? and $ rats.