Administration of human chorionic gonadotropin with a controlled-release function to immature rats for application in male infertility therapy

Biodegradable poly(or-lactic acid) (PLA) devices with controlled release of human chorionic gonadotropin (hCG) were fabricated in a 2-mm cylinder form by the melt-pressing technique. The devices fabricated were inserted subcu taneously in the backs of immature rats. It was found that the serum level of testosterone (T) remained constant at approximately 0.7 ng/ml for an exp erimental period of 14 days, resulting in greater Leydig cell production of testosterone. This was also suggested from the results of immunohistochemi cal observation of the testis and weight changes of prostates, such as the ventral prostates and seminal vesicle.