Skip to main content

Activation of AKT/mammalian target of rapamycin signaling in the peripheral blood of women with premature ovarian insufficiency and its correlation with FMR1 expression

This article has been updated



The protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway regulates early follicular activation and follicular pool maintenance in female germline cells. Fragile X mental retardation 1 (FMR1) regulates folliculogenesis and it is variably expressed in patients with Premature Ovary Insufficiency. FMR1 expression is supposed to be linked to AKT/mTOR signaling in an ovarian response dependent manner as demonstrated in recent in vitro and in vivo studies in the female germline in vitro and in vivo.


We evaluated changes in the expression of AKT/mTOR signaling pathway genes by real time PCR in the peripheral blood of 74 patients with Premature Ovarian Insufficiency and 56 fertile controls and correlated their expression with FMR1 expression.


Expression of the genes AKT1, TSC2, mTOR, and S6K was significantly more abundant in patients with POI than in the controls. For AKT1, TSC2 and mTOR, gene expression was not affected by FMR1-CGG repeat number in the 5´-untranslated region. FMR1 and S6K expression levels, however, were significantly upregulated in patients with POI and an FMR1 premutation. Independent of a premutation, expression of mTOR, S6K, and TSC2 was significantly correlated with that of FMR1 in all patients. Furthermore, when grouped according to ovarian reserve, this effect remained significant only for mTOR and S6K, with higher significance note in patients with Premature Ovarian Insufficiency than in the controls.


In Premature ovarian insufficiency patients, activation of AKT/mTOR signaling pathway is remarkable and putatively pathognomonic. Additionally, it seems to be triggered by an FMR1/mTOR/S6K linkage mechanism, most relevant in premutation carriers.


Severe or complete ovarian exhaustion before the age of 40 years is referred to as premature ovarian insufficiency (POI) or premature ovarian failure syndrome [1, 2]. It is characterized by hypergonadotropic oligo- to amenorrhea (> four months) [3]. POI development is multifactorial and is caused by various pathognomonic reasons including chromosomal and genetic aberrations, autoimmune and metabolic diseases (such as galactosaemia, and polyglandular autoimmune syndromes), infections (such as mumps), and iatrogenic treatments [2]. Approximately 1% of women are affected by POI, with 4–30% having a familial element, suggesting the involvement of a genetic component [4, 5]. Several genetic factors and signaling pathways are thought to play crucial roles at different times during folliculogenesis [6]. Folliculogenesis is affected by various factors as described before and ovarian reserves can range from high, above normal, to poor and eventually exhausted at different ages. The transition from physiologically normal to pathologically abnormal reserves is hard to detect. Therefore, identification of key functional steps in ovarian aging, folliculogenesis, and its associated disorders and ovarian reserves are highly needed.

The phosphatidylinositol-3-kinase (AKT)/mammalian target of rapamycin (mTOR) signaling pathway is essential to folliculogenesis, as it maintains the primordial follicular pool. This pathway is functionally involved in primordial follicle activation, granulosa cell (GC) proliferation, oocyte-GC, inter-GC communication, and cell cycle proliferation [7, 8]. Moreover, experimental AKT activation induces follicular maturation in patients with POI [9], and AKT1 expression in cumulus cells might serve as a marker for a positive pregnancy outcome [10].

The FMR1 gene (encoding fragile X-mental retardation 1 protein [FMRP], OMIM: *309,550, localized at Xq27.3) is involved in folliculogenesis and associated disorders [11]. Experimental animal studies have found that FMR1 is required for both germ stem cell maintenance and repression of primordial germ cell differentiation [12]. Moreover, this gene contains a variable CGG base triplet in its 5´-untranslated region (UTR) that is subject to premutation (PM) during expansion of 55–200 nt. Premutation alleles and so-called gray zone alleles (45–54 repeats) are associated with the development of POI in up to 13% of patients and can expand from one generation to the next. This condition is also called fragile X POI (FXPOI, OMIM #311,360) and is the most common monogenic cause of POI [13]. Elevated FMR1 mRNA levels in PM carriers are associated with reduced FMRP levels, reflecting a negative feedback mechanism between FMR1 and FMRP [14], which can induce several ovarian damage mechanisms [15, 16]. Additionally, distinct FMR1 gene expression due to different lengths of CGG repeats before premutation, defined as different genotypes, affect the ovarian reserve prior to POI [17, 18]. However, large variations in leukocyte FMR1 expression in patients with POI without PM have also been identified [19]. Furthermore, analysis of transcriptional changes in peripheral blood of FMR1 PM carriers demonstrated CGG repeat length-dependent downregulation of genes involved in inflammation, neuronal development, apoptosis, and proliferation. One of these highly downregulated genes was AKT1 [20].

FMRP can bind target RNAs within the RNA-interference silencing complex (RISC) [21], thereby regulating the storage, degradation, and translation of their own gene transcripts as well as other gene transcripts. Furthermore, FMRP can bind complementary 3′-UTRs in target mRNAs via their secondary structures (G-quadruplex RNA) [22]. Some of these target genes are located within the mTOR signaling pathway, including tuberous sclerosis complex 2 (Tsc2) and mTOR, as detected in ovarian studies of Fmr−/− mice [23].

We previously identified a putative functional linkage of FMR1/FMRP expression with mTOR/AKT signaling under maintenance of the FMR1/FMRP negative feedback loop, which can be altered by specific inhibition of mTOR [24]. In addition, we recently identified significant correlations between the expression of FMR1 and that of AKT1, TSC2, mTOR, and S6K (encoding ribosomal protein S6 kinase) in fresh GCs from women undergoing controlled ovarian stimulation for in vitro fertilization/intracytoplasmic sperm injection with either a normal or a poor response [25]. However, these relationships have not yet been evaluated in the peripheral blood of patients with POI and might differ according to tissue-specific expression and disease-specific alterations. Importantly, GCs in women with POI cannot be evaluated owing to ovarian exhaustion, and the detection of genes involved in AKT/mTOR signaling and putative correlations with FMR1 in peripheral blood might offer new perspectives for women at risk of POI and associated disorders.

Accordingly, the present study aimed to determine the expression of genes involved in the AKT/mTOR signaling pathway and their putative correlations with FMR1 in leukocytes from the peripheral blood of patients with POI and normal fertile controls (FCs), and to assess the value of these targets as predictive markers or tools in the diagnosis and prognosis of POI.

Material and methods

Design and patients

This prospective, observational, clinical study proceeded at the University Women’s Hospital (Heidelberg, Germany) between February 2017 and October 2020. Written, informed consent to participate in the study was obtained from 74 women with POI and 56 who were fertile (FCs). POI was defined based on the European Society for Human Reproduction and Embryology criteria [3]. The local ethics committee at Ruprecht-Karls-University, Heidelberg, Germany approved this study (ID: S-602/2013), which was conducted according to the principles of the Declaration of Helsinki (2013 amendment). Blood samples were collected from all patients and controls.

DNA and RNA extraction

Samples of DNA and RNA were prepared in parallel from 20 mL of blood samples collected into tubes containing ethylenediaminetetraacetic acid as described previously [1]. Total RNA was primed with oligo dT using the SuperScript First-Strand Synthesis System (Invitrogen GmbH, Darmstadt, Germany; cat. no.: 11904–018) and M-MLV Reverse Transcriptase RNase H Minus, Point Mutant of Promega (Promega Corp., Madison, WI, USA; cat. no.: M 3683) to synthesize cDNA.

Analysis of CGG repeat length

We analyzed CGG repeat lengths in the 5′-UTR of FMR1 (NM_002024.5) exon 1 in patients with POI, using polymerase chain reaction (PCR) and an ALFexpress™ DNA sequencer (Amersham 1050; Pharmacia Biotech, Freiburg, Germany) or an ABI 3100/3130xl sequencer (Thermo Fisher Scientific Inc., Waltham, MA, USA) as described previously [17]. Since May 2020, CGG repeat lengths were analyzed using POI Triplet Repeat Primed Polymerase Chain Reaction (PCR, TP-PCR, and AmplideX® PCR/CE FMR1 Kits; Asuragen Inc., Austin, TX, USA) as per the manufacturer’s protocol, and fragments were separated using a SeqStudio Genetic Analyzer (Thermo Fisher Scientific Inc.). Electropherograms were analyzed using GeneMapper™ v. 5 software (Thermo Fisher Scientific Inc.).

Gene expression analysis

TaqMan predesigned gene expression assays for FMR1 (Hs00924544_m1), AKT1 (Hs00178289_m1), mTOR (Hs00234508_m1), S6K (Hs00177357_m1), TSC2 (Hs01020387_m1), two housekeeping genes HPRT and TBP (Hs99999909_m1; Hs00427620_m1, respectively), and TaqMan universal PCR master mix were obtained from Thermo Fisher Scientific Inc. and performed as per the manufacturer’s protocol and as described previously [25]. All samples were analyzed in triplicates under standard qPCR conditions on a Fast Forward 7500 real-time PCR system (Thermo Fisher Scientific Inc.). Relative gene expression was analyzed using the ΔΔCt method [26]. The cDNA obtained from a lymphoblastoid cell line derived from fertile women was used as the calibrator in each run.

Statistical analysis

The data distribution was determined using Shapiro–Wilk tests. Between-group comparisons of POI vs. FCs and PM carriers vs. non-PM carriers were analyzed using Mann–Whitney tests. Not all data were normally distributed; hence, correlations were analyzed using the Spearman correlation coefficient rho (ρ).

Results are presented as medians with interquartile ranges (25th to 75th percentiles). All data were analyzed using the Statistical Package for the Social Sciences v. 27.0 (IBM Corp., Armonk, NY, USA), and values with p < 0.05 were considered statistically significant.


Gene expression of AKT1, TSC2, mTOR, S6K, and FMR1

The expression of FMR1 was slightly more abundant in peripheral blood from patients with POI than in FCs, although the difference was not significant. By contrast, AKT1, TSC2, mTOR, and S6K were significantly upregulated in women with POI compared with controls (Table 1).

Table 1 AKT1, TSC2, mTOR, and S6K expression in patients with premature ovarian insufficiency vs. fertile controls

Effects of CGG repeat length on gene expression levels in patients with POI

We found that FMR1-PM, FMR1, and S6K were significantly upregulated in patients with POI (Table 2).

Table 2 Expression of FMR1, AKT1, TSC2, mTOR, and S6K premutation vs non-premutation carriers


Patients were older in the FC group than in the POI group (32.5 ± 3.9 vs. 30.2 ± 7.2 y, p = 0.029). Therefore, the activation of mTOR/AKT signaling due to increased age in patients with POI can be excluded.

Correlations between FMR1 and AKT1, TSC2, mTOR, and S6K

The mRNA expression of mTOR and S6K positively and significantly correlated with that of FMR1 in all patients. These results were consistent after subgroup analysis of patients with POI and FCs. By contrast, the correlation between the expression of TSC2 and FMR1 was less significant, and was not observed after subgroup analysis. The expression of AKT1 and FMR1 did not correlate at the gene level in either group or in all patients together (Table 3).

Table 3 Correlations between FMR1 and AKT/mTOR signaling pathway genes


This study aimed to elucidate putative changes in the AKT/mTOR signaling pathway in lymphocytes isolated from the peripheral blood of women with POI compared with women with normal fertility and to determine whether these genes correlate with FMR1 gene expression. This is also clinically interesting as it can potentially identify new markers of ovarian reserve that can improve prediction of ovarian responses during artificial reproductive technologies. Anti-mullerian hormone and antral follicle count are currently the most relevant ovarian reserve markers, followed by age and follicle-stimulating hormone -values; however, these markers have less predictive value in cases of deviant ovarian responses, such as high or poor responses [27,28,29]. The results observed in the present study in patients with POI are in line with our previous data from germline cells of women with different ovarian responses during controlled ovarian stimulation [24]. Thus, identification of such novel markers that can be used in addition or alternative to existing markers in different patient groups are highly needed.

The expression of FMR1/FMRP is controlled through a negative feedback loop [14] and FMRP, as part of the RISC, interacts with other proteins from the Argonaute family as well as with coding and noncoding RNAs to regulate the translation of various proteins [21, 22]. In the female germline, FMRP is a major regulator of folliculogenesis, and changes in gene expression, genotype, and epigenetics (variable methylation status) are associated with disordered folliculogenesis from diminished ovarian reserve until POI [13, 18, 19, 30].

Both TSC2 and mTOR are putative binding partners of FMR1/FMRP in Fmr−/− mice [23]. The AKT/mTOR signaling pathway plays important roles in various cellular functions via AKT activation, TSC1/TSC2 dimerization, and mTOR activation. Finally, mTOR complex 1 phosphorylates S6K, further regulating cell-specific translation. In the female germline, AKT/mTOR signaling participates in early and late follicular maturation and GC differentiation [31,32,33].

The present study analyzed gene expression in lymphocytes of peripheral blood from women with normal fertility and women with POI. We found significantly more abundant AKT1, TSC2, mTOR, and S6K expression in patients with POI. Premature recruitment of oocytes therefore fit the data from experimental rodent models. Indeed, elevated mTOR and S6K levels in Fmr-knockout mice lead to premature oocyte recruitment [34]. In addition, we observed that mTOR and S6K was correlated with FMR1 expression in both groups, but significantly correlated in patients with POI. These results further supported the mechanism observed in experimental animals [34] and were consistent with our data from GCs of women with poor ovarian response, in whom mTOR signaling was similarly linked to FMR1 and particularly to S6K [25]. As expected from the findings of previous studies, the expression of FMR1 was significantly more abundant in patients with POI and PM than with POI without PM [9]. Notably, S6K was the only gene in the AKT/mTOR pathway with a simultaneous upregulation in PM carriers. These results are consistent with findings in human neuronal cells, in which S6K is supposed to be a major FMRP-phosphorylating enzyme [35] and suggest that S6K is one of the most promising linkage partner of the AKT/mTOR pathway with FMR1. Noteworthy, although it was not yet significant, is the downregulation of AKT1 that was observed in patients with POI with PM compared to those without PM. These results are consistent with previous transcriptome results from affected males carrying an FMR1 PM [20], and highlight the putative role of AKT/mTOR signaling in FMR1 related disorders, such as FXPOI and diminished ovarian reserve (DOR).

If FMR1/FMRP levels are functional traits in orchestrated follicular maturation, that are linked to mTOR signaling transmitted by, or triggered through mTOR and/or S6K binding, our findings might support further studies and the development of therapeutic approaches. The easy and direct detection of these targets in peripheral blood could facilitate their application as prospective diagnostic tools for women with diminished ovarian reserve and could help estimate their individual risk for POI development.

The AKT/mTOR pathway is related to longevity, and its inhibition is thought to provide protection against age-related pathologies [36]. Therefore, our results could help identify pre-existing conditions or pathological mechanisms associated with premature ovarian aging. Alternatively, our findings might reflect a compensatory mechanism targeting the activation of the last remaining follicles in POI, which would be consistent with initial therapeutic trials of activation in vitro, where AKT activators induced further follicular maturation and development in women with POI [9].

Our results provide the first evidence that activation of the AKT/mTOR signaling pathway in POI is putatively linked to FMR1 in patients with POI, diagnosed using peripheral blood probes. However, our patient cohort was small and not aged matched. Therefore, studies in larger cohort with women with distinct ovarian reserves and ages are needed to evaluate this finding in the complex context of folliculogenesis and progression to POI. The impact of CGG repeat length of this postulated relationship also needs further evaluation in longitudinal studies. Moreover, the results of both groups could be affected by age, although the average age in our cohort was below 35 years. Additionally, women in the control group were slightly older than the POI group, which contradicts age related AKT activation in POI observed in our study.


FMR1 premutation is a known risk factor for the development of POI and is recommended for clinical testing during diagnosis [3]. We believe that FMR1/FMRP regulates proper follicular maturation not only via its premutated CGG repeat length, but also through multiple other ways. In this context, we presumed a functional linkage between FMR1 and the AKT/mTOR signaling pathway based on the findings of previous studies [10, 17, 23,24,25]. In the present study, we demonstrated upregulated AKT/mTOR signaling in patients with POI that might reflect a pathognomonic reason for POI development or represent a compensatory mechanism for POI. A linkage with FMR1/FMRP, presumably via modified S6K and mTOR binding, could be a functional regulator of this pathogenic mechanism and is perhaps most relevant in PM carriers, and could perhaps be more predictive than age as ovarian reserve marker in patients below 40 years of age. However, further studies are needed to elucidate the regulatory mechanisms. The detectability of these conditions in the peripheral blood of patients reflects conditions within the germline, and offers further perspectives in diagnostics and pathognomonic investigation of POI.

Availability of data and materials

The datasets used and analyzed during the current study are available from the corresponding author on reasonable request.

Change history

  • 22 July 2022

    Funding note has been added.



Protein kinase B/mammalian target of rapamycin


Diminished ovarian reserve


Fertile control

FMR1 :

Fragile X mental retardation 1


Fragile X mental retardation 1 protein


Fragile X-associated POI


Granulosa cell


Premature ovary insufficiency




Tuberous sclerosis complex 2


RNA-interference silencing complex


Ribosomal protein S6 kinase


Untranslated region


  1. Fassnacht W, Mempel A, Strowitzki T, Vogt PH. Premature Ovarian Failure (POF) Syndrome: Towards the Molecular Clinical Analysis of Its Genetic Complexity. Curr Med Chem. 2006;13:1397.

    Article  CAS  Google Scholar 

  2. Goswami D, Conway GS. Premature Ovarian Failure. Hum Reprod Update. 2005;11:391.

    Article  CAS  Google Scholar 

  3. Webber L, Davies M, Anderson R, Bartlett J, Braat D, Cartwright B, et al. European Society for Human Reproduction and Embryology (ESHRE) Guideline: Management of Women with Premature Ovarian Insufficiency. Hum Reprod. 2016;31:926.

    Article  CAS  Google Scholar 

  4. Conway GS. Premature Ovarian Failure. Curr Opin Obstet Gynecol. 1997;9:202.

    Article  CAS  Google Scholar 

  5. Krauss CM, Turksoy RN, Atkins L, McLaughlin C, Brown LG, Page DC. Familial Premature Ovarian Failure due to an Interstitial Deletion of the Long Arm of the X Chromosome. N Engl J Med. 1987;317:125.

    Article  CAS  Google Scholar 

  6. Sobinoff AP, Sutherland JM, McLaughlin EA. Intracellular Signalling during Female Gametogenesis. MHR Basic science of reproductive medicine. 2013;19:265.

    Article  CAS  Google Scholar 

  7. Sánchez F, Smitz J. Molecular Control of Oogenesis. Biochem Biophys Acta. 2012;1822:1896.

    PubMed  Google Scholar 

  8. Zuccotti M, Merico V, Cecconi S, Redi CA, Garagna S. What Does It Take to Make a Developmentally Competent Mammalian Egg? Hum Reprod Update. 2011;17:525–40.

    Article  Google Scholar 

  9. Kawamura K, Kawamura N, Hsueh AJ. Activation of Dormant Follicles: a New Treatment for Premature Ovarian Failure? Curr Opin Obstet Gynecol. 2016;28:217.

    Article  Google Scholar 

  10. Artini PG, Tatone C, Sperduti S, D’Aurora M, Franchi S, Di Emidio G, et al. Italian Society of embryology, Reproduction and Research (SIERR). Cumulus Cells Surrounding Oocytes with High Developmental Competence Exhibit Down-Regulation of Phosphoinositol 1,3 Kinase/Protein Kinase B (PI3K/AKT) Signalling Genes Involved in Proliferation and Survival. Human Reprod. 2017;32:2474.

    Article  CAS  Google Scholar 

  11. Eichler EE, Richards S, Gibbs RA, Nelson DL. Fine Structure of the Human FMR1 Gene. Hum Mol Genet. 1993;2:1147.

    Article  CAS  Google Scholar 

  12. Yang L, Duan R, Chen D, Wang J, Chen D, Jin P. Fragile X Mental Retardation Protein Modulates the Fate of Germline Stem Cells in Drosophila. Hum Mol Genet. 2007;16:1814.

    Article  CAS  Google Scholar 

  13. Conway GS, Payne NN, Webb J, Murray A, Jacobs PA. Fragile X Premutation Screening in Women with Premature Ovarian Failure. Hum Reprod. 1998;13:1184.

    Article  CAS  Google Scholar 

  14. Kenneson A, Zhang F, Hagedorn CH, Warren ST. Reduced FMRP and Increased FMR1 Transcription Is Proportionally Associated with CGG Repeat Number in Intermediate-Length and Premutation Carriers. Hum Mol Genet. 2001;10:1449.

    Article  CAS  Google Scholar 

  15. Kong HE, Zhao J, Xu S, Jin P, Jin Y. Fragile X-Associated Tremor/Ataxia Syndrome: from Molecular Pathogenesis to Development of Therapeutics. Front Cell Neurosci. 2017;11:128.

    Article  Google Scholar 

  16. Man L, Lekovich J, Rosenwaks Z, Gerhardt J. Fragile X-Associated Diminished Ovarian Reserve and Primary Ovarian Insufficiency from Molecular Mechanisms to Clinical Manifestations. Front Mol Neurosci. 2017;10:290.

    Article  Google Scholar 

  17. Rehnitz J, Alcoba DD, Brum IS, Dietrich JE, Youness B, Hinderhofer K, et al. FMR1 Expression in Human Granulosa Cells Increases with exon 1 CGG Repeat Length Depending on Ovarian Reserve. Reprod Biol Endocrinol. 2018;16:65.

    Article  Google Scholar 

  18. Gleicher N, Weghofer A, Oktay K, Barad D. Relevance of Triple CGG Repeats in the FMR1 Gene to Ovarian Reserve. Reprod Biomed Online. 2009;19:385.

    Article  CAS  Google Scholar 

  19. Schuettler J, Peng Z, Zimmer J, Sinn P, von Hagens C, Strowitzki T, et al. Variable Expression of the Fragile X Mental Retardation 1 (FMR1) Gene in Patients with Premature Ovarian Failure Syndrome Is Not Dependent on Number of (CGG)n Triplets in exon 1. Hum Reprod. 2011;26:1241.

    Article  CAS  Google Scholar 

  20. Mateu-Huertas E, Rodriguez-Revenga L, Alvarez-Mora MI, Madrigal I, Willemsen R, Milà M, Martí E, Estivill X. Blood expression profiles of fragile X premutation carriers identify candidate genes involved in neurodegenerative and infertility phenotypes. Neurobiol Dis. 2014;65:43–54.

    Article  CAS  Google Scholar 

  21. Schaeffer C, Beaulande M, Ehresmann C, Ehresmann B, Moine H. The Rna Binding Protein Fmrp New Connections and Missing Links. Biology of the Cell June. 2003;95(3–4):221–8.

    Article  CAS  Google Scholar 

  22. Pratt AJ, MacRae IJ. The RNA-Induced Silencing Complex: a Versatile Gene-Silencing Machine. J Biol Chem. 2009;284:17897.

    Article  CAS  Google Scholar 

  23. Ascano M Jr, Mukherjee N, Bandaru P, Miller JB, Nusbaum JD, Corcoran DL, et al. FMRP Targets Distinct mRNA Sequence Elements to Regulate Protein Expression. Nature. 2012;492:382.

    Article  CAS  Google Scholar 

  24. Rehnitz J, Alcoba DD, Brum IS, Hinderhofer K, Youness B, Strowitzki T, et al. FMR1 and AKT/mTOR Signalling Pathways: Potential Functional Interactions Controlling Folliculogenesis in Human Granulosa Cells. Reprod Biomed Online. 2017;35:485.

    Article  CAS  Google Scholar 

  25. Rehnitz J, Capp E, Messmer B, Nguyen XP, Germeyer A, Freis A, et al. FMR1 and AKT/MTOR Signaling in Human Granulosa Cells: Functional Interaction and Impact on Ovarian Response. Clin Med. 2021;30(10):3892.

    Google Scholar 

  26. Winer J, Jung CK, Shackel I, Williams PM. Development and Validation of Real-Time Quantitative Reverse Transcriptase-Polymerase Chain Reaction for Monitoring Gene Expression in Cardiac Myocytes In Vitro. Anal Biochem. 1999;270:41.

    Article  CAS  Google Scholar 

  27. La Marca A. Sunkara SK (2014) Individualization of controlled ovarian stimulation in IVF using ovarian reserve markers: from theory to practice. Hum Reprod Update. 2014;20:124–40.

    Article  Google Scholar 

  28. Di Paola R, Garzon S, Giuliani S, et al. Are we choosing the correct FSH starting dose during controlled ovarian stimulation for intrauterine insemination cycles? Potential application of a nomogram based on woman’s age and markers of ovarian reserve. Arch Gynecol Obstet. 2018;298:1029–35.

    Article  Google Scholar 

  29. Peluso C, Oliveira R, Laporta GZ, Christofolini DM, Fonseca FLA, Laganà AS, Barbosa CP, Bianco B. Are ovarian reserve tests reliable in predicting ovarian response? Results from a prospective, cross-sectional, single-center analysis. Gynecol Endocrinol. 2021;37(4):358–66.

    Article  CAS  Google Scholar 

  30. Rehnitz J, Youness B, Nguyen XP, Dietrich JE, Roesner S, Messmer B, et al. FMR1 Expression in Human Granulosa Cells and Variable Ovarian Response Control by Epigenetic Mechanisms. MHR Basic science of reproductive medicine. 2021;27:001.

    Article  CAS  Google Scholar 

  31. Ford EA, Beckett EL, Roman SD, McLaughlin EA, Sutherland JM. Advances in Human Primordial Follicle Activation and Premature Ovarian Insufficiency. Reproduction. 2020;159:R15.

    Article  CAS  Google Scholar 

  32. Kayampilly PP, Menon KMJ. Follicle-Stimulating Hormone Increases Tuberin Phosphorylation and Mammalian Target of Rapamycin Signaling through an Extracellular Signal-Regulated Kinase-Dependent Pathway in Rat Granulosa Cells. Endocrinology. 2007;148:3950.

    Article  CAS  Google Scholar 

  33. Guo Z, Yu Q. Role of MTOR Signaling in Female Reproduction. Front Endocrinol. 2019;10:692.

    Article  Google Scholar 

  34. Mok-Lin E, Ascano M Jr, Serganov A, Rosenwaks Z, Tuschl T, et al. Premature Recruitment of Oocyte Pool and Increased mTOR Activity in Fmr1 Knockout Mice and Reversal of Phenotype with RapamycinScientific Reports. Sci Rep. 2018;8:588.

    Article  CAS  Google Scholar 

  35. Narayanan U, Nalavadi V, Nakamoto M, Thomas G, Ceman S, Bassell GJ, et al. S6K1 Phosphorylates and Regulates Fragile X Mental Retardation Protein (FMRP) with the Neuronal Protein Synthesis-Dependent Mammalian Target Of Rapamycin (mTOR) Signaling Cascade. J Biol Chem. 2008;283:18478.

    Article  CAS  Google Scholar 

  36. Johnson SC, Rabinovitch PS, Kaeberlein M. mTOR Is a Key Modulator of Ageing and Age-Related Disease. Nature. 2013;493:338.

    Article  CAS  Google Scholar 

Download references


We thank our coworkers at the outpatient clinic of our department for the continuous enrollment of patients.


This study was funded by the German Research Foundation (grant no. RE 3647–1-2 to JR). EC is a scholarship recipient from CNPq—Conselho Nacional de Desenvolvimento Científico e Tecnológico, Brazil. Open Access funding enabled and organized by Projekt DEAL.

Author information

Authors and Affiliations



Each author contributed substantially to the drafting or critical revision of the manuscript, and approved the final version. J.R. conceived and designed the study with the support of E.C. Data acquisition, analysis, and interpretation, and statistical analyses were performed by J.R., E.C., U.B., X.P.N., K.H., U.B., B.M., A.G., and T.S. The author(s) read and approved the final manuscript.

Corresponding author

Correspondence to Julia Rehnitz.

Ethics declarations

Ethics approval and consent to participate

The study was conducted according to the guidelines of the Declaration of Helsinki and approved by the Institutional Review Board of Ruprecht-Karls-University Heidelberg, Germany (number S-602/2013). Informed consent was obtained from all patients involved in the study.

Consent for publication

Not applicable.

Conflicts of interests

The authors declare no conflicts of interest.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Rehnitz, J., Messmer, B., Bender, U. et al. Activation of AKT/mammalian target of rapamycin signaling in the peripheral blood of women with premature ovarian insufficiency and its correlation with FMR1 expression. Reprod Biol Endocrinol 20, 44 (2022).

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: