"The effect of hCG-induced desensitization on RNA synthesis in rat Leydig cells".

In this study we have examined the effect of hCG-induced desensitization on RNA synthesis in rat Leydig cells. In vitro [3H]-uridine incorporation into RNA decreased after a high, single dose of hCG (100 IU). This effect was maximal after the second and third day of treatment. When Leydig cells were incubated in vitro for 30 min or more, a marked decrease of total and poly(A)+ RNA synthesis was observed. This was not due to reduced cell permeability to the radioactive nucleotide, indicating a truly decreased RNA synthesis during desensitization. The magnitude of this inhibitory effect (73-80%) suggests that desensitization may involve other biological functions of Leydig cell.