Injection sites and pharmacokinetics of luteinizing hormone releasing hormone: comparison of two different subcutaneous administration routes.

A normal pituitary-gonadal function is reinduced by iv or sc pulsatile LHRH therapy, administered by a portable pump. In order to evaluate the differences between different sites of injection on the LHRH bioavailability, we compared the LHRH plasma concentration after a single LHRH injection in the lower abdominal wall and in the upper arm, in 5 patients with idiopathic hypogonadotropic hypogonadism, during LHRH treatment. Our data showed no significant differences in using both administration routes. In fact, LHRH absorption (secretory area and peak value) is quite similar. However, patients tolerated LHRH administration in the abdominal wall more so than in the upper arm. Both ways of administration are effective with regards to the pituitary responsiveness but we can not forget that patients compliance is of great importance in order to obtain the best results in a long-term therapy.