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Follitropin, an important gonadotropin hormone, participates in vitellogenesis and spermatogenesis. Equine chorionic gonadotropin (eCG) can induce gonadotropin hormone activity in non-equid species and exhibits a long biological half-life. Here, we report the production, using silkworm larval and pupal systems, of biologically active recombinant hybrid-type follitropins based on the coding sequence of the eCG C-terminal peptide (CTP) between the mature β- and α-chains of eel. The three constructs, rJeFSH, rJeFSH·eCG, and rJeFSH·2xeCG were produced and verified to be N- or O-glycosylated and secreted mature peptides. Although rJeFSH·eCG contains more elaborate O-linked carbohydrate chains than rJeFSH, it elicited no significant in vitro oocyte maturation, which may be a result of insufficient terminal sialylation of its N-and O-linked carbohydrate chains. Then, a hybrid of rJeFSH·2xeCG extended with two eCG CTP. Furthermore, the receptor binding assay revealed potency of rJeFSH and rJeFSH·2xeCG to be a few folds greater than that of rJeFSH·eCG. The findings of this study will be useful for the development of more efficient GTHs in teleosts, including eels, when various modifications with two or more extended eCG CTP produced by silkworm are included.

Purpose: To compare the efficiency and efficacy of two recombinant human FSH (r-FSH) and urinary (u-FSH) preparations in patients undergoing superovulation for IVF-ET using a short-term gonadotropin releasing hormone agonist (GnRH-a) (Triptorelin) protocol. Methods: A total of 88 women undergoing IVF-ET were included in this prospective study. They were randomized to receive u-FSH (150 IU/d), follitropin-α (100 IU/d), or follitropin-β (100 IU/d) for 2 days, and dosages were subsequently adjusted according to the ovarian response. Results: The FSH dose required for the overall stimulation was significantly lower in patients treated with r-FSH than in those treated with u-FSH while serum FSH values were higher in the latter group. There were no statistically significant differences in ovarian response and IVF outcome between r-FSH preparations. Conclusions: Recombinant FSH preparations have a higher efficiency than urinary ones in patients undergoing IVF-ET using a short-term GnRH-a protocol. In this situation, the two recombinant follitropins have comparable effectiveness.

Recombinant gonadotrophins, in particular recombinant follitropin (follicle-stimulating hormone; FSH), are now available for ovarian hyperstimulation for assisted reproduction. In contrast with urinary FSH (urofollitropin), follitropin is available in virtually unlimited quantities. Follitropin is as potent as urofollitropin in all protocols of ovarian stimulation. Furthermore, it shows an improved purity without contamination by urinary proteins not related to FSH, and can be injected subcutaneously by the patients themselves. In patients with complete luteinising hormone (LH) deficiency, follitropin stimulates follicular development, although serum levels of estradiol remain low. For this group of patients the addition of LH is necessary. Ongoing phase III studies on the use of recombinant LH in this indication will provide an answer to how much LH is needed in order to guarantee sufficient follicular growth and hormonal response. Gonadorelin (gonadotrophin releasing hormone; GnRH) analogues are used to avoid the surge of endogenous LH in ovarian stimulation protocols. Gonadorelin antagonists are now in clinical testing for the same indication. Gonadorelin antagonists allow sufficient suppression of endogenous LH levels. In contrast with gonadorelin analogues, they avoid any flare-up effect, i.e. an initial release of gonadotrophins from pituitary reservoirs. Recombinant gonadotrophins and gonadorelin antagonists are new tools towards a more individual approach to ovarian stimulation.

These data compare the efficacy and safety of highly purified human-derived follicle-stimulating hormone (Bravelle(R)) and recombinant follitropin-β (Follistim(R)) in women undergoing in vitro fertilization. This report describes the pooled data from two, nearly identical, randomized, controlled, parallel-group, multicenter studies conducted in a total of 19 academic and private IVF-ET centers in the United States. Infertile premenopausal women underwent pituitary down-regulation using leuprolide acetate followed by a maximum of 12 days of subcutaneous Bravelle(R) (n = 120) or Follistim(R) (n = 118), followed by administration of human chorionic gonadotropin, oocyte retrieval and embryo transfer. The primary efficacy measure was the mean number of oocytes retrieved; secondary efficacy measures included the total dose and duration of gonadotropin treatment; peak serum estradion levels; embryo transfer and implantation rates; chemical, clinical and continuing pregnancies; and live birth rates. All adverse events were recorded and injection site pain was recorded daily using a patient, self-assessment diary. Similar efficacy responses were observed for all outcome parameters in the two treatment groups. Although patients receiving Bravelle(R) consistently reported a greater number of chemical, clinical and continuing pregnancies, as well as an increased rate of live birth, the data did not attain statistical significance (P > 0.05). The overall incidence of adverse events was similar in both groups, but compared to Follistim(R), injections of Bravelle(R) were reported by patients to be significantly less painful (P < 0.001). Bravelle(R) and Follistim(R) had comparable efficacy in controlled ovarian hyperstimulation in women undergoing IVF-ET. There were no differences in the nature or number of adverse events between the treatment groups although Bravelle(R) injections were reported to be significantly less painful.

A collaborative study from two laboratories has been undertaken to re-evaluate the human follitropin beta-subunit sequence (hFSH beta), since areas of uncertainty remain in the wake of two earlier reports. The first report was by Shome and Parlow (1974). The second, by Saxena and Rathnam (1976), proposed revisions for sequence not definitively placed in the first study, as well as some differences in other placements. We have re-examined the sequence of the hFSH beta with more recent methodology. This has led to revision of certain areas of the sequence and resolution of differences between the two earlier proposals. Specifically, an -Ile-Ser- is established at 21-22, Asp at 41, Arg at 44, Lys at 46, and Glu at 111. These were areas of disagreement in the earlier proposals. A definitive placement of the residues around tryptophan-27 has now been obtained by three laboratories. C-terminal heterogeneity was observed with subunits ending at residue 107, 109, or 111. N-terminal heterogeneity has been observed in all preparations examined to date. A significant population of molecules with a proteolytic nick between residues 38-39 is noted. This is very likely an artifact of the collection and processing. The preparations examined in the present studies showed no evidence of residues 112-118 proposed by Saxena and Rathnam.

We have reevaluated the sequence of porcine follicle-stimulating hormone (pFSH) with more recent protein-sequencing methodology. This has led to revision of the earlier proposed sequence. As with almost all reported gonadotropin alpha-subunits, NH2-terminal heterogeneity was found in the porcine FSH alpha-subunit (FSH alpha), starting with residue Phe (1), Asp (3), Gly (4), or Thr (7). In the beta-subunit, there were found to be at least two molecular species, starting with residue Asn (1) (minor 20%) or Cys (3) (major 80%) as NH2-terminal and ending at residue Glu (108) as COOH-terminal. The net effect of the present revisions is to increase the homology of pFSH beta with other reported follitropin sequences. Apparent differences in the half-cystine placements in a previous proposal for pFSH beta compared with other species of FSH are no longer tenable. The half-cystine placements thus remain a constant structural feature throughout the gonadotropin hormones (choriogonadotropin, follitropin, and lutropin).

Adult cycling female rats were treated with antisera to highly purified human follitropin and lutropin for eight days. The effect of this treatment on thein vitro steroidogenic response of the ovarian cells isolated from these rats to follitropin and lutropin has been investigated. Neutralisation of follitropin did not have significant effect on steroid production in response to lutropin. However, neutralisation of lutropin resulted in a very significant inhibition of response to both follitropin and lutropin.

The sialic acid residues of human chorionic gonadotropin, human lutropin and human follitropin were quantitatively modified by introduction of an amino compound. In radioreceptor assays, the modified chorionic gonadotropin, lutropin and follitropin saturated the receptors. However, in the low nanogram range, the gonadotropic binding was higher for the control compared to the modified sample.

A study of the problem of structural variants of proteins and their relative contribution to the expressed immunological and biological activity has been initiated using sheep and buffalo prolactins as models. The feasibility of obtaining immunologically and biologically active prolactin in high yields from the discarded ’acid pellet’ of sheep and buffalo pituitaries has been demonstrated. This permits use of the same batch of glands for purifying lutropin, follitropin and prolactin as side fractions. The major component in preparations of buffalo prolactin has a molecular size of 24 kDa. The preparations were active in a radioligand binding inhibition assay and in a rat liver based radioreceptor assay. Charge and size isomers of sheep prolactin and buffalo prolactin have been observed. The reference sheep prolactin did not, in preliminary work, give any indication of being glycosylated. However radioactive sulphate was found to be incorporated into prolactin-rich fractions of sheep and buffalo pituitariesin vitro. By physico-chemical and immunochemical criteria the [35S]-labelled material was similar to standard reference prolactin. The structural implications of sulphation have been probed.