INTENDED USE

This Human FSH ELISA Kit is to be used for the in vitro quantitative determination of human follicle stimulating hormone (FSH) concentrations in serum. This kit is intended FOR LABORATORY RESEARCH USE ONLY and is not for use in diagnostic or therapeutic procedures.

INTRODUCTION

Follicle-Stimulating Hormone (FSH) and Luteinizing Hormone (LH) are intimately involved in the control of the growth and reproductive activities of the gonadal tissues, which synthesize and secrete male and female sex hormones. The levels of circulatingFSHand LH are controlled by these sex hormones through a negative feedback relationship.

FSHis a glycoprotein secreted by the basophil cells of the anterior pituitary. Gonadotropin-releasing hormone (GnRH), produced in the hypothalamus, controls the release ofFSHfrom the anterior pituitary. Like other glycoproteins, such as LH,TSH, and HCG,FSHconsists of subunits designated as alpha and beta. Hormones of this type have alpha subunits that are very similar in structure; therefore the biological and immunological properties of each are dependent on the unique beta subunit.

In the female,FSHstimulates the growth and maturation of ovarian follicles by acting directly on the receptors located on the granulosa cells; follicular steroidogenesis is promoted and LH production is stimulated. The LH produced then binds to the theca cells and stimulates steroidogenesis. Increased intraovarian estradiol production occurs as follicular maturation advances, thereupon stimulating increasedFSHreceptor activity andFSHfollicular binding.FSH, LH and estradiol are therefore intimately related in supporting ovarian recruitment and maturation in women.FSHlevels are elevated after menopause, castration, and in premature ovarian failure. The levels ofFSHmay be normalized through the administration of estrogens, which demonstrate a negative feedback mechanism. Abnormal relationships betweenFSHand LH and betweenFSHand estrogen have been linked to anorexia nervosa and polycystic ovarian disease. Although there are significant exceptions, ovarian failure is indicated when randomFSHconcentrations exceed 40 mIU/mL.

The growth of the seminiferous tubules and maintenance of spermatogenesis in men are regulated by FSH. However, androgens, unlike estrogens, do not lower FSH levels, therefore demonstrating a feedback relationship only with serum LH. For reasons not fully understood, azospermic and oligospermic males usually have elevated FSH levels. Tumors of the testes generally depress serum FSH concentrations, but levels of LH are elevated, as determined by radioimmunoassay. It has been postulated that the apparent LH increase may be caused by cross-reactivity with hCG-like substances secreted by tumors of the testes. High levels of FSH in men may be found in primary testicular failure and Klinefelter syndrome. Elevated concentrations are also present in cases of starvation, renal failure, hyperthyroidism, and cirrhosis.

PRINCIPLE OF THE ASSAY

This FSH enzyme linked immunosorbent assay (ELISA) applies a technique called a quantitative sandwich immunoassay. The microtiter plate provided in this kit has been pre-coated with a monoclonal antibody specific forFSH. Standards or samples are then added to the microtiter plate wells andFSHif present, will bind to the antibody pre-coated on the wells. In order to quantitate the amount ofFSHpresent in the sample, a standardized preparation of horseradish peroxidase (HRP) conjugated monoclonal antibody specific forFSHis added to each well to “sandwich” theFSHimmobilized on the plate. The microtiter plate undergoes incubation, and then the wells are thoroughly washed to remove all unbound components. Next, aTMB (3,3",5,5" Tetramethyl-benzidene) substrate solution is added to each well. This enzyme (HRP) and substrate are allowed to react over a short incubation period. Only those wells that containFSHand enzyme-conjugated antibody will exhibit a change in colour. The enzyme-substrate reaction is terminated by the addition of a sulphuric acid solution and the colour change is measured spectrophotometrically at a wavelength of 450 nm.

In order to measure the concentration of FSH in the sample this Human FSH ELISA Kit includes a set of calibration standards (6 standards). The calibration standards are assayed at the same time as the samples and allow the operator to produce a standard curve of Optical Density (O.D.) versus FSH concentration (mIU/mL). The concentration of FSH in the samples is then determined by comparing the O.D. of the samples to the standard curve.

CITATIONS

1. Q Xu et al. Br J Cancer. Isolation of tumour stem-like cells from benign tumours. Jul 21, 2009; 101(2): 303–311.

2.Akyol S, Cınar SA, Purisa S, Aydinli K. Relationship between lymphocytes, IL2 and the hormones E2, LH, PRG and FSH in menopausal and postmenopausal women. Am J Reprod Immunol. 2011 Oct;66(4):304-9.