Ranta T, Chen H C, Jalkanen J, Nikula H, Shimohigashi Y, Huhtaniemi I
Obstet Gynecol. 1987 Aug;70(2):171-4.
The receptor binding properties and biologic actions of chemically deglycosylated-asialo human choriogonadotropin (AHF-hCG) were studied in human ovary and testis. In corpus luteum and testis homogenates, the relative binding affinity of AHF-hCG was two- to fourfold higher in the ovary and five- to tenfold higher in the testis than that of native hCG. When assayed for luteinizing hormone (LH)-like activity in granulosa-luteal cells from in vitro fertilization patients and in testicular minces from patients undergoing orchiectomy for prostatic cancer, AHF-hCG did not stimulate cyclic adenosine monophosphate production. When added with hCG to granulosa-luteal cells or to testicular minces, AHF-hCG inhibited hCG-stimulated cyclic adenosine monophosphate production. These results indicate that the enhanced affinity to LH receptor caused by removal of the sugar moieties from hCG is associated with total inability to activate granulosa-luteal and Leydig cell adenylate cyclase, and that AHF-hCG is, in the human gonad, an hCG antagonist.
