Influence of Follicle-Stimulating Hormone on the Prostate Assay of Luteinizing Hormone (LH, ICSH)

Abstract

In view of previous reports on the augmenting effect of prolactin and growth hormone (GH) on the measurement of luteinizing hormone (LH, ICSH) by the hypophysectomized rat prostate (HRP) bio-assay of Greep, the influence of ovine follicle-stimulating hormone (FSH) on this method was examined. LH potency of various preparations obtained from ovine pituitary glands determined by the HRP method was compared with that obtained by the ovarian ascorbic acid depletion (OAAD) bio-assay of Parlow, as the latter method is unaffected by prolactin, GH or FSH. The LH potency of an aqueous homogenate of whole, unfractionated ovine pituitary glands, in terms of NIH-LH-S1, was found to be 4.9 times higher in the HRP system than in the OAAD system. On the other hand, the potencies of 2 partially purified ovine LH preparations determined by the HRP and OAAD methods were in excellent agreement. However, the amount of LH contamination of 4 partially purified ovine FSH preparations determined by the HRP method was always higher than that obtained by the OAAD method. This discrepancy increased as the FSH:LH ratio of these ovine FSH preparations became larger. Administration of ovine FSH simultaneously with ovine LH augmented the prostatic response. It is concluded that ovine FSH influences measurement of ovine LH by the HRP assay. The mere presence of FSH is not sufficient to exert this influence. A certain minimal ratio of FSH:LH activity is necessary to bring about the augmentation effect.