Human pituitary gonadotropin index. I. Standardized LRH test criteria for evaluation of functional amenorrhea.
LRH test were carried out by giving 339 amenorrheic women and 74 normally menstruating volunteers an intravenous injection of 25 mug LRH (Hoe 471). Plasma LH and FSH were measured by RIA in two laboratories (Tuebingen and Ulm) using two standard reference preparations: LER 907 and 2nd IRP-HMG. The average conversion factors between the two standard preparations were calculated at 5.0 for LH and 25.0 for FSH. Furthermore, the estradiol-17beta levels were measured in 139 out of the 339 patients immediately before and 60 minutes after LRH injection. Taking the episodic and cyclic plasma gonadotropin fluctuations into consideration a shorthand system classifying the gonadotropin baseline (BI-BIV) and LH responses to 25 mug LRH (R0-R2) has been established and is referred to as Human Pituitary Gonadotropin Index (HPGI). It is possible to achieve reproducible gonadotropin results in two different laboratories using two different standard reference preparations. Two separate, randomly selected groups of amenorrheic women were found to have the same percent distribution of the HPGI. A correlation coefficient of r equal 0.67 between basal and LRH stimulated plasma LH levels does not sufficiently characterize the individual LH response behavior. A significant increase of plasma LH and FSH within the test period (60') reveals that the iv administration of 25 mug LRH represents an adequate dose for the LRH test in women. The HPGI which characterizes the functional state of gonadostat, may become a useful diagnostic index for evaluating women with anovulatory disease before, during, and after therapy.