[Restricted importance of LRH test in clinical routine diagnosis (author's transl)]

The pituitary responsiveness to luteinising hormone releasing hormone (LRH) was studied in 68 women aged between 15 and 30 years. The patients suffered from primary and secondary amenorrhoea or anovulatory cycles in combination with hirsutism, primary sterility, oligo-amenorrhoea, adrenogenital syndrome, and nervous anorexia. Eleven women without any discernible endocrinological disorders were used as controls. Double stimulation was performed by two intravenous injections of 25 microgram LRH each, spaced by one two-hour interval. Blood samples were taken repeatedly prior to, between, and after the injections at intervals set beforehand. Luteinising hormone (LH) plasma concentrations were determined by radio-immuno-assay. The mean difference between the two basic values measured ten and five minutes before LRH application was as low as 20.1 per cent. In most cases, the maximum values occurred 30 minutes after both injections. A positive correlation (r = 0.91, p < 0.001) was found to exist between the level recordable 30 minutes after the first injection and the integral of all values included. Dependence of response to LRH application on the height of the basic values was more strongly pronounced than that on the underlying category of disease. The LRH test, perhaps, may be indicated in cases of low basic LH values (< 2 ng/ml) to verify suspicion of a hypogonadotrophic situation. Simplification of the test procedure to only one withdrawal of blood each immediately before and 30 minutes after LRH injection seems to be justified.