Common misconceptions about LH and FSH
Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) are gonadotropin glycoprotein hormones. This research-use-only article examines misconceptions about their roles, mechanisms, and study contexts, citing onl
What are LH and FSH?
Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) are gonadotropin glycoprotein hormones. They are also known as lutropin and follitropin, respectively. Both are heterodimeric proteins composed of a common alpha subunit and a hormone-specific beta subunit. The alpha subunit is shared with thyroid-stimulating hormone (TSH) and human chorionic gonadotropin (hCG). The beta subunits confer receptor specificity: LH beta and FSH beta. Molecular weights are approximately 28–30 kDa for LH and 30–35 kDa for FSH, though exact values depend on glycosylation. These hormones are produced by gonadotroph cells in the anterior pituitary and are regulated by gonadotropin-releasing hormone (GnRH) from the hypothalamus.
The work centres on the hypothalamic-pituitary-gonadal (HPG) axis and the G-protein-coupled receptors for LH (LHCGR) and FSH (FSHR), which are expressed primarily on gonadal cells.
Research Studies
Follitropin alfa/lutropin alfa and LH/FSH deficiency in Japanese participants undergoing ART
A clinical study (HINATA) assessed the efficacy and safety of follitropin alfa/lutropin alfa versus human menopausal gonadotropin (hMG) in Japanese participants with LH and FSH deficiency undergoing assisted reproductive technology (ART) [1]. The study duration was approximately 5.5 months for nonpregnant participants and 13 months for participants with confirmed pregnancy in Part A [1]. This trial directly addresses a misconception that exogenous gonadotropins are only for specific populations; here, the population is defined by documented deficiency.
Clomiphene or enclomiphene citrate and male hypogonadism: effects on LH, FSH, and testosterone
A systematic review and meta-analysis of randomized controlled trials evaluated selective estrogen receptor modulators (SERMs), specifically clomiphene and enclomiphene, in men with functional hypogonadism [2]. The primary endpoints included total testosterone (TT), follicle-stimulating hormone (FSH), and luteinizing hormone (LH) [2]. This evidence challenges the misconception that SERMs act only on estrogen receptors without affecting gonadotropins; the study measured LH and FSH as primary outcomes.
GLP-1 agonist and neuro-reproductive function in obese adolescent females with PCOS
A study examined the effects of a glucagon-like peptide-1 (GLP-1) agonist on neuro-reproductive function in obese adolescent females with polycystic ovary syndrome (PCOS) [3]. The background notes that normal puberty onset and progression depend on the hypothalamic-pituitary-gonadal (HPG) axis, which is affected by whole-body metabolism [3]. Gonadotropin-releasing hormone (GnRH) and gonadotropins, LH and FSH, are released in a pulsatile manner for appropriate sex steroid production and gonadal function [3]. Proper pulsatility in the GnRH system is disrupted by significant changes in energy balance such as obesity [3]. This contradicts the misconception that LH and FSH act independently of metabolic status.
Comparison of gonadotropin regimens in ART
The HINATA study compared follitropin alfa/lutropin alfa with hMG in a specific population [1]. The table below summarises the key features of the two treatments as reported in the study.
| Treatment | Components | Population | Study duration |
|---|---|---|---|
| Follitropin alfa/lutropin alfa | Recombinant FSH and LH | Japanese participants with LH and FSH deficiency undergoing ART | ~5.5 months (nonpregnant); 13 months (pregnant, Part A) |
| hMG | Human menopausal gonadotropin (FSH and LH activity) | Same as above | Same as above |
This comparison addresses the misconception that all gonadotropin preparations are identical in composition or effect.
SERMs and gonadotropin levels in men
The meta-analysis of clomiphene and enclomiphene included randomized controlled trials comparing SERMs with placebo, testosterone gel, or human chorionic gonadotropin (hCG) [2]. The primary endpoints were total testosterone, FSH, and LH [2]. This evidence contradicts the misconception that SERMs do not influence the HPG axis in men.
Metabolic disruption of GnRH pulsatility
The PCOS study highlights that proper pulsatility in the GnRH system is disrupted by significant changes in energy balance such as obesity [3]. This challenges the misconception that LH and FSH secretion is solely governed by gonadal feedback, ignoring metabolic inputs.
Animal and in vitro evidence
The evidence block does not provide animal-only or in vitro studies for LH and FSH. All cited studies are clinical trials or systematic reviews of randomized controlled trials in humans [1][2][3]. Therefore, no claims are made about animal or in vitro models.
Misconception: LH and FSH are only relevant to fertility
The HINATA study focuses on ART, but the PCOS study links LH and FSH to neuro-reproductive function and metabolism [1][3]. The male hypogonadism meta-analysis includes LH and FSH as primary endpoints in a non-fertility context [2]. This shows that LH and FSH are relevant beyond fertility, contradicting the misconception.
Misconception: LH and FSH levels are static
The PCOS study describes pulsatile release of GnRH and gonadotropins, which is disrupted by obesity [3]. This indicates that LH and FSH levels are dynamic and influenced by metabolic state, contradicting the misconception that they are static.
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Sources
- [1] A Study to Compare the Efficacy and Safety of Follitropin Alfa/Lutropin Alfa Versus hMG in Japanese Participants With LH and FSH Deficiency Undergoing ART (HINATA)
- [2] Clomiphene or enclomiphene citrate for the treatment of male hypogonadism: a systematic review and meta-analysis of randomized controlled trials.
- [3] Effects of Glucagon-like Peptide-1 (GLP-1) Agonist in Neuro-reproductive Function in Obese Adolescent Females With Polycystic Ovary Syndrome (PCOS)