Long term treatment with luteinising hormone releasing hormone agonists and maintenance of serum testosterone to castration concentrations.

Serum concentrations of luteinising hormone and testosterone were measured by radioimmunoassay one, two, four, seven, and 24 hours after the subcutaneous administration of 500 micrograms of the luteinising hormone releasing hormone agonist [D-Trp6, des-Gly-NH2(10)] LHRH ethylamide or [D-Ser(TBU)6, des-Gly-NH2(10)]LHRH ethylamide in patients who had previously received daily treatment with these peptides for 0, 1, 6, 12, 18, and 24 months. No increase in the serum concentrations of luteinising hormone or testosterone were detected at any time between one and 24 months' treatment. The data show that daily subcutaneous administration of the two luteinising hormone releasing hormone agonists used at the appropriate dose can maintain concentrations of serum androgens equivalent to those after castration during long term treatment.