Effects Of The (imBzl)D-His6, Des-Gly Analog Of GnRh On Gonadotropin And Estradiol Secretion In Normal Women

Abstract

The acute gonadotropin and estradiol [E2] responses following single s.c. injections of 10, 50, 100 and 200 .mu.g of [(imBzl)D-His6, Pro9-NEt]-GnRH were compared to those after 100 .mu.g of [D-Trp6, Pro9-NEt]-GnRH. The gonadotropin responses after 50-100 .mu.g of the D-His analog of GnRH were equivalent to those following 100 .mu.g of the D-Trp analog. The ovarian E2 response, a reflectin of the total cumulative secretion of gonadotropins, was similar at 100 .mu.g of each analog. The E2 response paralleled the increasing gonadotropin response accompanying the graded doses of the D-His analog, indicating the lack of a direct inhibitory action of this GnRH agonist on the ovary. Assessment of both gonadotropin and E2 responses appears to be satisfactory for assessing relative potency among GnRH agonistic analogs.