ON THE NATURE OF THE FOLLICLE-STIMULATING SIGNAL DELIVERED TO THE OVARY DURING EXOGENOUSLY CONTROLLED FOLLICULAR MATURATION - A SEARCH INTOTHE IMMUNOLOGICAL AND BIOLOGICAL ATTRIBUTES AND THE MOLECULAR COMPOSITION OF 2 PREPARATIONS OF UROFOLLITROPIN

In the present study, we analyzed the immunological and biological pot encies as well as the molecular composition of urinary follicle-stimul ating hormone (FSH) present in determined lots of regular and highly p urified (HP) commercial preparations of urofollitropin in order to obt ain additional insights on the particular type of gonadotropin signal received by the ovary during exogenously regulated ovarian stimulation . In both preparations, a high degree of FSN charge heterogeneity was detected as disclosed by chromatofocusing analysis (pH range 7.5 to <4 .0), Urinary FSH present in the HP compound was consistently more acid ic and exhibited a longer survival in rat circulation than the regular formulation. Inter-batch variability for FSH heterogeneity and in vit ro bioactivity was higher in the partially purified preparation than i n the HP analog. In the regular preparation, the amount of immunoreact ive and bioactive FSH per ampule was two times higher than that presen t in the HP preparation; the resultant in vitro B/I ratios were simila r. Although both urinary FSH preparations showed detectable amounts of immunoreactive and bioactive luteinizing hormone and choriogonadotrop in hormone material, the degree of activity present in the less purifi ed formulation was considerably higher than that shown by the HP analo g. When the capability of each urinary FSH preparation to induce ovari an tissue-type plasminogen activator enzyme activity in hypophysectomi zed rats was determined, both formulations exhibited similar potencies despite the existing differences in plasma clearance rate and charge distribution profile. The present study indicates that the isoform com position of urinary FSH in the two commercial preparations analyzed di ffers according to the degree of purity of the formulation. More FSH m aterial is needed in the partially purified FSH preparation to induce biological effects similar in magnitude to those exhibited by the high ly purified analog. The possible impact of these variations in the mol ecular composition of the FSH signal on other biological functions of the ovary during the course of exogenously controlled follicular growt h and maturation still remains to be ascertained.