Inhibition of ovalbumin glycopeptides on the hCG signal transduction system

Rat testicular cells dispersed by 0.03% collagenase digestion were seperated by discontinuous/continuous of Percoll, yielding highly pure Leydig cell fraction. 0.52 nmol/L hCG 0.1 mumol/L cholera toxin and 10 mumol/L forskolin signifcantly stimulated production of cAMP (Cholera toxin > Forskolin > hCG) and testosterone (no signifcient differences among cholera toxin, Forskolin and hCG). Ovalbumin glycopeptides prepared by extensive pronase digestion significantly inhibited production of cAMP and testosterone of rat testis Leydig cells stimulated by hCG, cholera toxin and forskolin. These results suggest that the carbohydrate moiety of hCG participate in the signal transduction among receptor, G-protein and adenylatecyclase which is inhibited by Asn-linked oligosaccharide chains from ovalbumin glycopeptides.