Definition and Measurement of Follicle Stimulating Hormone

Abstract

FSH has a key role in the development and function of the reproductive system and is widely used both diagnostically and therapeutically in developmental and reproductive medicine. The accurate measurement of FSH levels, in patients for diagnosis and monitoring and in therapeutic preparations for clinical use, is essential for safe and successful treatment. Historically, FSH was defined on the basis of classical in vivo endocrine activity, and early therapeutic preparations were calibrated using in vivo bioassays. There was early recognition that reference preparations were required for calibration if the results from different laboratories were to be comparable. In response to the perceived need, the World Health Organization established the first standard for such preparations in 1959. Subsequent developments in biotechnology have led to recognition that there is no single molecule that can be uniquely defined as FSH, and that FSH can induce a range of biological activities. Several highly purified standards for FSH are now available, but discontinuity and heterogeneity of estimates of FSH activity in terms of these standards made using in vitro assays and binding assays have been noted. It is thus essential that any measurement of FSH include specification both of the standard with which the measured FSH is compared and the assay method used for that comparison.

Use of a single injection of long-acting recombinant bovine FSH to superovulate Holstein heifers: A preliminary study

“…The degree of glycosylation of the FSH molecule plays a critical role in both the metabolic clearance rate by the liver and kidney and the in vitro and in vivo bioactivity of the molecule (for a review see [13,26–28]). Heifers treated with B50-LArbFSH had greater superovulatory responses and produced more embryos compared with heifers treated with A50-LArbFSH, but a similar response to heifers treated with A100-LArbFSH (Table 2).…”

LH and hCG Action on the Same Receptor Results in Quantitatively and Qualitatively Different Intracellular Signalling

“…Due to this heterogeneity and derivation from extractive preparations, gonadotropins have been difficult to quantify accurately in the past, and most in vitro experiments have been conducted using urinary hCG calibrated by in vivo bioassay against standard preparations expressed in activity units [14]. With the advent of recombinant gonadotropins, highly homogeneous and consistent r-hLH and r-hCG can be accurately quantified in molar terms [15] and used to compare their effects in vitro at exactly equimolar concentrations.…”

Reliability of follicle-stimulating hormone measurements in serum

“…The accurate and reliable measurement of FSH levels is essential for safe and successful treatment in developmental and reproductive medicine [1], as well as for research studies examining the association between FSH levels and various disease outcomes.…”

“…The measurement of FSH in circulation is employed in the diagnosis of disorders of reproduction and development, whereas therapeutic preparations of FSH are widely used for induction of ovulation in women and stimulation of spermatogenesis in men [1]. The effects of gonadotropins may not be limited to endocrine and reproductive functions.…”