Biological Activity Of Follicle-stimulating Hormone Research Articles

Determination of biological activity of gonadotrophins in inbred and outbred animals. Part 1: Determination of biological activity of follicle-stimulating hormone

Scientific relevance. The biological activity of medicinal products may vary depending on the method of production (i.e. biological or recombinant products). The widening variety of gonadotrophin preparations, the diversity of their production methods, and the irreplaceability of biological activity bioassays with physicochemical tests require improvement of animal testing conditions.Aim. This study aimed to determine the biological activity of follicle-stimulating hormone (FSH) in several rat lines, analyse the findings, and select the most optimal testing conditions.Materials and methods. The biological activity was determined using in vivo methods. The comparative analysis used test results obtained over several years in inbred and outbred rats treated with FSH. In all cases, the authors used a three-dose randomised method based on the determination of the biological activity of test samples by comparison with that of the WHO international standard (IS) containing 183 IU of FSH bioactivity and 177 IU of LH bioactivity per ampoule (NIBSC code: 10/286). The study included immature female rats, inbred (Wistar-Kyoto or Sprague Dawley) and outbred. Testing conditions depended on the selected rat line, with the main variables being the test dose and the number of animals per group.Results. The authors compared responses of inbred and outbred rats to various doses of the FSH IS and test samples. Given the narrow range of the analytical procedure, Wistar-Kyoto rats showed a relatively weak dose–response relationship. The study demonstrated that the doses and testing duration depended on the sensitivity of the animals. Test results were less variable in inbred rats than in outbred ones. The statistical analysis of the results of FSH bioactivity testing in inbred and outbred rats showed that, with inbred rats, the number of animals could be halved without compromising the validity of the test.Conclusions. The approach proposed in this study provides for testing the biological activity of FSH with fewer experimental animals, improved cost-effectiveness, and the same reliability of results.

The Observation of FSH’s Cellular Internalization

Follicle stimulating hormone (FSH) is a kind of glycoprotein gonadotropin, and plays an important role in the diagnosis and treatment of infertility. Follicle stimulating hormone receptor (FSHR) is a kind of G protein coupled receptor (GPCR), found in the ovary and testes, and its activation is required for the hormonal operation during the breeding period. In this study, an experimental model of FSHR mediated FSH into cell membrane, which exhibited a phenomenon of fluorescent localized on cell surfaces internalized into cell interior, was established to verify biological activity of FSH.

The Effect of Species-Specific FSH Administration During In vitro Maturation of Bovine Oocytes on Embryonic Developmental Capability

Follicle-stimulating hormone (FSH) is a heterodimeric glycoprotein synthesized and secreted by the anterior pituitary gland under hypothalamic control. This hormone is involved in the regulation of essential mammalian reproductive processes such as gametogenesis, follicular growth, and ovulation. An important aspect of the structure of FSH is its double species-specificity, at both the amino acid and sugar level. In fact, both the amino acid sequence and the oligosaccharide structure significantly differ among species (Green and Baenziger, 1988; Wallis, 2001). For example, bovine (bFSH) and human FSH (hFSH) differ by 45 amino acids (sequence identity: α-subunit 75%; β-subunit 90%), and in addition they show strikingly different profiles with respect to their oligosaccharide side-chains (the relative distribution of sialylated, sulfated and neutral Asn-linked oligosaccharides in human FSH is 88%, 7% and 5%, while in the bovine it is 56%, 13% and 31%). Both protein and sugar structures affect the biological activity of FSH (e.g. hormonereceptor interactions)(Ulloa-Aguirre et al., 2003), however, the molecular basis of FSH functions in domestic animals are usually studied by heterologous experimental models. Examples are the in vitro bioassays based on rat and mouse primary cultures of Sertoli and granulosa cells, and the bioassays based on recombinant cell lines expressing the cloned FSH rat and human receptors (Christin-Maitre and Bouchard, 1996). Another non speciesspecific application involves the use of supraphysiological doses of recombinant hFSH or pituitary pig FSH during in vitro bovine embryo production (IVP) protocols (Ali and Sirard, 2002). The objective of the present study was to develop a species-specific in vitro bioassay to study the molecular mechanisms underlying the biological activity of bovine FSH (bFSH). We used cumulus-oocyte complexes (COCs) isolated from bovine ovaries in order to evaluate the ability of pituitary bFSH to stimulate cumulus expansion, and blastocyst development

Physiological roles of FSH and LH in red seabream, Pagrus major

The duality of gonadotropins (GTHs), follicle-stimulating hormone (FSH) and luteinizing hormone (LH), has been confirmed in most teleost species, but very little is known about their biological functions. To elucidate the physiological roles of FSH and LH in fish reproduction, the expression profiles of GTH subunit genes during gonadal development were analyzed in both male and female red seabream. Furthermore, in vitro studies were carried out to examine the effects of GTHs on steroid hormone production and cytochrome P450 aromatase (P450arom) expression in red seabream gonads. In both sexes, LHβ mRNA was maintained at high levels from the early gametogenesis until spawning season, and declined with gonadal regression. Interestingly, FSHβ mRNA levels in males increased in parallel with testicular development, whereas those in female were remained low throughout oocyte development. From in vitro studies using purified red seabream FSH and LH, both GTHs had a similar potency in stimulating 11-ketotestosterone production by testicular slices, while the biological activity of FSH was much lower than that of LH in stimulating production of estradiol-17β by vitellogenic follicles. Moreover, expression of P450arom mRNA was induced by LH, but not FSH, in ovarian follicles in vitro. FSH was also ineffective in inducing maturational competence and final oocyte maturation. These results suggest that, unlike salmonids, FSH may play an important role during gametogenesis in male, but not female, red seabream, whereas LH may be involved in regulation of both early and late gametogenesis in both sexes.

In vitro inhibition of the biological activity of follicle-stimulating hormone by anti-peptide antisera representing the human follicle-stimulating hormone beta subunit sequence 33-53.

There are few male contraceptive methods, and research is required to broaden the scope of available male antifertility methods. Two approaches toward hormonal contraception are currently being investigated. The first relies on elimination of testosterone while the second is based upon immunizations against FSH. However, most anti-whole FSH antisera cross-react with LH, thereby possibly inhibiting testosterone and leading to potential loss of libido. Therefore, a more effective alternative would be to define an FSH peptide that differs significantly from LH in order to prevent cross-reactivity between anti-FSH antisera and LH. Two peptides were selected from the beta subunit of FSH that were considered to be inducers of anti-FSH activity but not anti-LH activity. The first peptide (sequence beta33-53) is a linear antigenic site of human FSH found only in anti-FSH antisera that do not cross-react with LH. The second peptide (sequence beta81-95) is a part of FSH that confers receptor specificity. These peptides, in monomer and tandem form, were used to immunize rabbits. The antisera were tested for inhibition of FSH activity in a bioassay; they were also tested in a Leydig cell assay to detect anti-LH activity. It was found that antisera raised against the beta33-53 tandem could inhibit the FSH bioactivity but not that of LH. Antisera against the beta33-53 monomer or the beta81-95 monomer or tandem did not inhibit FSH. Thus, the tandem peptide beta33-53 is an attractive candidate for use as antigen in a male contraceptive vaccine. The better results obtained with tandem vaccinations might be related to the ability of the tandem peptide to direct the antibody response toward the N-terminal end of the peptide and to raise antisera with the ability to react with shorter chains of amino acids.

Biological activity of follicle-stimulating hormone in the human fetal pituitary

Changes in the follicle-stimulating hormone (FSH) level in the human fetal pituitary were studied by biological methods. FSH was detected in the fetal pituitary throughout the period of investigation: from the 8th to the 34th week. From the 17th to the 34th week of intrauterine development considerable sex differences were found both in the total and the relative content of the hormone in the gland.