LH receptor gene mutations and polymorphisms: an overview.
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Alleles↗
Biomedical subjects
Axel P N Themmen
Publications and source records attributed to Axel P N Themmen.
Anti-Müllerian hormone levels in the spontaneous menstrual cycle do not show substantial fluctuation.
CONTEXT: Anti-Müllerian hormone (AMH), a quantitative marker for ovarian reserve, has been suggested to be independent of the classical endocrine fluctuations of the menstrual cycle. OBJECTIVE: The objective of the study was to determine whether AMH levels are constant throughout the menstrual cycle, compared with those of FSH, LH, and estradiol. DESIGN/PATIENTS: Frequent blood sampling was performed in 44 fertile, regularly cycling, female volunteers during one full menstrual cycle. SETTING: The study was conducted at a university hospital. MAIN OUTCOME MEASURES: AMH, FSH, LH, and estradiol measurements were allocated to one of seven cycle phases, and a multilevel analysis was performed. Consistent fluctuation patterns were tested by fitting sine patterns to the data. Finally, the frequency in which randomly selected individual samples would remain in one of five preset level categories (quintiles) for each of the variables was studied. RESULTS: A sine pattern fitted to the AMH data was not statistically significant (P = 0.40). In contrast, sine patterns for FSH, LH, and estradiol were highly significant. Comparing the seven cycle phases, no significant differences could be observed between phase-specific AMH levels (P = 0.06). Repeated selection of AMH samples for each individual showed that in 71.5% of selections, AMH values remained in the same quintile, whereas in 27.9% values fell in an adjacent quintile. CONCLUSIONS: AMH levels measured through a full menstrual cycle did not show consistent fluctuation patterns in contrast to levels of FSH, LH, and estradiol. Furthermore, random fluctuations were small, indicating that AMH can be relied on as a cycle-independent marker for ovarian reserve.
Adult↗
Unacylated ghrelin is active on the INS-1E rat insulinoma cell line independently of the growth hormone secretagogue receptor type 1a and the corticotropin releasing factor 2 receptor.
Both unacylated ghrelin (UAG) and acylated ghrelin (AG) exert metabolic effects. To investigate the interactions between AG and UAG on ghrelin receptors we evaluated the effects of AG and UAG on INS-1E rat insulinoma cells, using insulin secretion after 30min static incubation as a read-out. A possible involvement of the growth hormone secretagogue receptor type 1a (GHS-R1a) or the corticotropin-releasing factor 2 (CRF2) receptor (CRF2R), as a putative receptor for UAG, was also studied determining their mRNA expression and the functional effects of receptor antagonists on insulin release. Both UAG and AG stimulated insulin release dose-dependently in the nanomolar range. The AG-induced insulin output was antagonized by two GHS-R1a antagonists ([d-Lys(3)]GHRP-6 and BIM28163), which did not block UAG actions. These effects occurred in the presence of low levels of GHS-R1a mRNA. Neither CRF2R expression nor effects of the CRF2R antagonist (astressin(2)B) on insulin output were observed. In conclusion, we provide a sensitive and reproducible assay for specific effects of UAG, which in this study is responsible for insulin release by INS-1E cells. Our data support the existence of a specific receptor for UAG, other than the CRF2R and GHS-R1a. The stimulatory effect on insulin secretion by AG in this cell line is mediated by the GHS-R1a.
Acylation↗
Serum anti-mullerian hormone levels reflect the size of the primordial follicle pool in mice.
Reproductive aging is the decline of female fertility with age. It is caused by the decrease in the number of growing follicles, resulting from primordial follicle pool depletion. Recently, we have shown that anti-Müllerian hormone (AMH) is produced by growing follicles, and studies in women indicate that serum AMH levels decrease with age and correlate with antral follicle count. However, whether serum AMH levels correlate directly with the size of the primordial follicle pool cannot be determined in women. In this work, we describe studies in mice in which we determined the dynamics of ovarian follicles during aging. Furthermore, we describe the development of a mouse AMH ELISA, allowing us to measure AMH levels in mice, for the first time. We observed that serum AMH levels decline with increasing age, whereas expression of AMH in individual growing follicles, studied by immunohistochemistry, did not change with age. Thus, the decline in serum AMH correlates directly with the decline in the number of growing follicles (r = 0.86, P < 0.0001). We observed that the number of growing follicles correlated with the number of primordial follicles (r = 0.93, P < 0.0001). Similarly, we found a strong correlation between AMH levels and number of primordial follicles (r = 0.83, P < 0.0001). In conclusion, serum AMH levels reflect the size of the primordial follicle pool in aging mice. Therefore, AMH is an excellent marker to assess the quantitative aspect of ovarian reserve, which may be useful for women at risk for early ovarian aging such as survivors of childhood cancers.
Aging↗
A common polymorphism renders the luteinizing hormone receptor protein more active by improving signal peptide function and predicts adverse outcome in breast cancer patients.
CONTEXT: Epidemiological and animal studies indicate a carcinogenic role of estrogens in breast tissue. The pituitary gonadotropin LH is an important regulator of estrogen production in premenopausal women, whereas even in women after menopause, 10-25% of ovarian steroid hormone production is LH dependent. OBJECTIVE: We hypothesized that an LH receptor (LHR) gene variant may affect LHR function and thereby influence disease outcome in breast cancer patients. DESIGN: The association of a polymorphic CTCCAG (Leu-Gln) insertion (insLQ), in the signal peptide encoded by exon 1 of the LHR gene with breast cancer risk, (disease-free) survival, and clinicopathological features was studied in a large cohort of 751 breast cancer patients with complete follow-up. Functional analysis of the insLQ-LHR and non-LQ-LHR (no LQ insertion) was carried out using transfection studies. RESULTS: We found a significant association between the insLQ-LHR and a shorter disease-free survival (hazard ratio, 1.34; confidence interval, 1.11-1.63; P = 0.003). The mechanism of the effect of insLQ on LHR function involves increased receptor sensitivity (insLQ-LHR has a 1.9 times lower EC(50) than non-LQ-LHR; P = 0.02) and plasma membrane expression (insLQ-LHR has 1.4 times higher B(max); P = 0.0006) rendering the insLQ-LHR allele more active. CONCLUSIONS: The insLQ polymorphism increases LHR activity, thereby shortening breast cancer disease-free survival, probably by increasing estrogen exposure in female carriers.
Adult↗
Use of ovarian reserve tests for the prediction of ongoing pregnancy in couples with unexplained or mild male infertility.
The chance of infertile patients conceiving is related to factors like female age and duration of infertility. This prospective observational study evaluated whether the results of ovarian reserve tests, including the novel marker serum anti-Mullerian hormone (AMH), were of additional value in predicting ongoing pregnancy. Two hundred and twenty-two patients diagnosed with unexplained infertility or mild male factor (total motile count>10x10(6)) on the basis of the infertility work-up were prospectively included. Antral follicle count, AMH, inhibin B, FSH and oestradiol concentrations were determined during the early follicular phase. Outcome measures were treatment-dependent and treatment-independent ongoing pregnancy and time to ongoing pregnancy. There were 159 ongoing pregnancies, 52 of which occurred spontaneously. Pregnant patients were significantly younger than those who did not become pregnant (median age 32.4 versus 34.9 years, P<0.001) and FSH concentrations were higher in non-pregnant patients (median 6.8 versus 7.6 IU/l, P=0.04). Only age (hazard ratio 0.93, 95% CI 0.90-0.97) and whether or not the patient was undergoing treatment (hazard ratio 8.10, 95% CI 5.66-11.61) were significantly associated with time to ongoing pregnancy. Ovarian reserve tests, other than chronological age, seem of limited value in predicting (time to) ongoing pregnancy in patients with unexplained and mild male infertility.
Adult↗
Anti-Müllerian hormone: a new marker for ovarian function.
Anti-Müllerian hormone (AMH) is a member of the transforming growth factor beta family of growth and differentiation factors. In the ovary, AMH has an inhibitory effect on primordial follicle recruitment as well as on the responsiveness of growing follicles to follicle-stimulating hormone (FSH). The ovary-specific expression pattern in granulosa cells of growing nonselected follicles makes AMH an ideal marker for the size of the ovarian follicle pool. This review summarizes recent findings concerning AMH and its role as a marker for the quantitative aspect of ovarian reserve as well as ovarian dysfunction.
Aging↗
Anti-müllerian hormone protein expression is reduced during the initial stages of follicle development in human polycystic ovaries.
CONTEXT: Polycystic ovary syndrome, the most common cause of anovulatory infertility, is characterized by disordered folliculogenesis, notably increased progression from the primordial to the primary stages. This ovarian phenotype is similar to that observed in mice lacking anti-müllerian hormone (AMH). OBJECTIVE: The objective of this study is to investigate whether AMH is involved in accelerating the transition of follicles from primordial to primary stages in polycystic ovaries. DESIGN: This study compares AMH expression in archive tissue from normal and polycystic ovaries. SETTING: This is a laboratory-based study. PATIENTS: Ovarian tissue from seven normoovulatory women and 16 women with polycystic ovaries (five of whom were anovulatory) was used in this study. Ovaries were classified by histology and with reference to menstrual cycle history and ultrasound. MAIN OUTCOME MEASURE: Presence and intensity of AMH expression in 1403 follicles was the main outcome measure. RESULTS: AMH was observed from the primordial stage onward. AMH immunostaining was observed in significantly fewer primordial (P = 0.007) and transitional follicles (P = 0.001) in ovaries from anovulatory women with polycystic ovaries compared with women with regular cycles and either normal or polycystic ovaries. AMH-negative follicles had fewer pregranulosa cells in the largest cross-section of the follicle at both the primordial (median, four and six for AMH-negative and -positive follicles, respectively; P < 0.0001) and transitional stages (median six and nine; P < 0.0007) in normal tissue, and fewer at the transitional stage (median, seven and 11; P < 0.0001) in tissue from anovulatory women with polycystic ovaries. This suggests that AMH expression is associated with granulosa cell mitosis. CONCLUSIONS: These findings indicate a relative deficiency of AMH in primordial and transitional follicles in ovaries from anovulatory women with polycystic ovaries. This may contribute to disordered early follicle development in polycystic ovary syndrome.
Adult↗
Anti-Müllerian hormone and folliculogenesis.
This paper reviews the role of anti-Müllerian hormone, a member of the TGF(beta) family signaling through a BMP-like pathway, in the ovary. In vivo and in vitro studies showed that AMH has an inhibitory effect on primordial follicle recruitment and it decreases the sensitivity of follicles for the FSH-dependent selection for dominance. Besides its functional role in the ovary, AMH serum level serves as an excellent candidate marker of ovarian reserve.
Animals↗
Serum antimullerian hormone levels best reflect the reproductive decline with age in normal women with proven fertility: a longitudinal study.
OBJECTIVE: The aim of this study was to assess which of the basal ovarian reserve markers provides the best reflection of the changes occurring in ovarian function over time (i.e., reproductive aging). DESIGN: Prospective longitudinal study. SETTING: Healthy volunteers in an academic research center. PATIENT(S): Eighty-one women with normal reproductive performance during the course of their lives were longitudinally assessed. In this select group of women, becoming chronologically older was considered as a proxy variable for becoming older from a reproductive point of view. INTERVENTION(S): The women were assessed twice, with on average a 4-year interval (T(1) and T(2)). The number of antral follicles on ultrasound (AFC) and blood levels of antimullerian hormone (AMH), FSH, inhibin B, and E(2) were assessed. MAIN OUTCOME MEASURE(S): Longitudinal changes of the markers mentioned and the consistency of these parameters over time. RESULT(S): The mean ages at T(1) and T(2) were 39.6 and 43.6 years, respectively. Although AFC was strongly associated with age in a cross-sectional fashion, it did not change over time. The AMH, FSH, and inhibin B levels showed a significant change over time, in contrast to E(2) levels. The AMH and AFC were highly correlated with age both at T(1) and T(2), whereas FSH and inhibin B predominantly changed in women more than 40 years of age. To assess the consistency of these parameters over time, we investigated whether a woman's individual level above or below the mean of her age group at T(1) remained above or below the mean of her age group at T(2). Serum AMH concentrations showed the best consistency, with AFC as second best. The FSH and inhibin B showed only modest consistency, whereas E(2) showed no consistency at all. CONCLUSION(S): These results indicate that serum AMH represents the best endocrine marker to assess the age-related decline of reproductive capacity.
Adult↗
Anti-Müllerian hormone: its role in follicular growth initiation and survival and as an ovarian reserve marker.
In this paper the role in the ovary of anti-Müllerian hormone (AMH), a member of the transforming growth factor-beta family of growth and differentiation factors, is reviewed. AMH has an inhibitory effect on primordial follicle recruitment and may also inhibit follicle-stimulating homone-dependent selection of follicles for dominance. In addition to its functional role in the ovary, AMH in serum is an excellent candidate marker as an indication of the ovarian reserve, not only in infertility clinic patients but also in women during and after cancer treatment.
Anti-Mullerian Hormone↗
An update of the pathophysiology of human gonadotrophin subunit and receptor gene mutations and polymorphisms.
New information about mutations and polymorphisms in the genes for the gonadotrophins and their receptors has become available in the last few years. In this short review mutations and polymorphisms in gonadotrophins, their receptors and their pathophysiological effects and implications are discussed. An increasingly clear picture about the structure-function relationships of gonadotrophin action is emerging from the combining the types and the locations of the mutations with their phenotypic effects and the information about the crystal structure of these molecules.
Gene Deletion↗
Changes in anti-Müllerian hormone serum concentrations over time suggest delayed ovarian ageing in normogonadotrophic anovulatory infertility.
BACKGROUND: Anti-Müllerian hormone (AMH), produced by growing pre-antral and early antral ovarian follicles, has been shown to be a useful marker for ovarian ageing. Serum AMH concentrations are elevated during reproductive life in anovulatory women, especially in those patients exhibiting polycystic ovaries (PCO). The current study was designed to investigate whether the decrease in AMH serum concentrations over time is different comparing women with normogonadotrophic anovulation [World Health Organization (WHO) group 2 (including polycystic ovary syndrome (PCOS)] and normo-ovulatory controls. METHODS AND RESULTS: AMH serum levels were assessed on two occasions in 98 patients suffering from WHO 2 anovulatory infertility as well as in 41 normo-ovulatory premenopausal women. Median time interval between both visits was 2.6 years (range 0.3-9.0) for WHO 2 patients compared with 1.6 years (range 1.0-7.3) in controls. Serum AMH concentrations were significantly (P < 0.0001) elevated on both occasions in WHO 2 patients (AMH1, median = 7.5 microg/l, range 0.1-35.8; and AMH2, median = 6.7 microg/l, range 0.0-30.6) compared with controls (AMH1, median = 2.1 microg/l, range 0.1-7.4; and AMH2, median = 1.3 microg/l, range 0.0-5.0). Regression analysis, corrected for age, indicated a significant relative decrease in serum AMH concentrations over time for both groups (P < 0.001). However, the decline in serum AMH in WHO 2 patients was significantly less compared with controls (P = 0.03). CONCLUSION: The present longitudinal study shows that serum AMH concentrations decrease over time both in women presenting with WHO 2 anovulatory infertility and in normo-ovulatory controls. The decrease in WHO 2 patients is less pronounced despite distinctly elevated concentrations. This observation may suggest retarded ovarian ageing and hence a sustained reproductive life span in these patients.
Adolescent↗
Cell-specific knockout of steroidogenic factor 1 reveals its essential roles in gonadal function.
Knockout (KO) mice lacking the orphan nuclear receptor steroidogenic factor 1 (SF-1, officially designated Nr5a1) have a compound endocrine phenotype that includes adrenal and gonadal agenesis, impaired expression of pituitary gonadotropins, and structural abnormalities of the ventromedial hypothalamic nucleus. To inactivate a conditional SF-1 allele in the gonads, we targeted the expression of Cre recombinase with a knock-in allele of the anti-Müllerian hormone type 2 receptor locus. In testes, Cre was expressed in Leydig cells. The testes of adult gonad-specific SF-1 KO mice remained at the level of the bladder and were markedly hypoplastic, due at least partly to impaired spermatogenesis. Histological abnormalities of the testes were seen from early developmental stages and were associated with markedly decreased Leydig cell expression of two essential components of testosterone biosynthesis, Cyp11a and the steroidogenic acute regulatory protein. In females, the anti-Müllerian hormone type 2 receptor-Cre allele directed Cre expression to granulosa cells. Although wild-type and SF-1 KO ovaries were indistinguishable during embryogenesis and at birth, adult females were sterile and their ovaries lacked corpora lutea and contained hemorrhagic cysts resembling those in estrogen receptor alpha and aromatase KO mice. Collectively, these studies establish definitively that SF-1 expression in the gonads is essential for normal reproductive development and function.
Animals↗
Insight into mutation-induced activation of the luteinizing hormone receptor: molecular simulations predict the functional behavior of engineered mutants at M398.
In this study, molecular simulations have been combined with site-directed mutagenesis experiments to explore M398(2.43), a LH (lutropin) receptor (LHR) site in helix 2 susceptible to spontaneous activating mutations, and to develop a computational tool for predicting the functionality (i.e. active or nonactive) of LHR mutants.Site-directed mutagenesis experiments engineered 15 different substitutions for M389(2.43), which resulted in variable levels of constitutive activity, inversely correlated with the size of the replacing amino acid. This inverse correlation is suggested to be mediated by I460(3.46), M571(6.37), and Y623(7.53), the tyrosine of the NPxxY motif. In fact, size reduction at position 398(2.43), which is concurrent with constitutive receptor activity, releases the van der Waals interactions found in the wild-type LHR between M398(2.43) and these three amino acids, resulting in structural modifications in the proximity to the E/DRY/W motif. An increment, above a threshold value, in the solvent accessibility of the cytosolic ends of helices 3 and 6 is the main structural feature shared by the active mutants of the LHR. This feature has been successfully used for predicting the functionality of the engineered mutants at M398(2.43), proving that molecular simulations can be useful for in silico screening of LHR mutants.
Amino Acid Motifs↗
Anti-Müllerian hormone expression pattern in the human ovary: potential implications for initial and cyclic follicle recruitment.
Anti-Müllerian hormone (AMH) is a member of the transforming growth factor-beta superfamily, which plays an important role in both ovarian primordial follicle recruitment and dominant follicle selection in mice. However, the role of AMH in folliculogenesis in humans has not been investigated in detail. In the present study, AMH expression was assessed using immunohistochemistry in ovarian sections, obtained from healthy regularly cycling women. To this end, a novel monoclonal antibody to human AMH was developed. AMH expression was not observed in primordial follicles, whereas 74% of the primary follicles showed at least a weak signal in the granulosa cells. The highest level of AMH expression was present in the granulosa cells of secondary, preantral and small antral follicles <or=4 mm in diameter. In larger (4-8 mm) antral follicles, AMH expression gradually disappeared. In conclusion, in the human AMH expression follows a similar pattern as compared to the mouse and rat, suggesting an important role of AMH in folliculogenesis.
Adolescent↗
Anti-Müllerian hormone and its role in ovarian function.
Anti-Müllerian hormone (AMH) is expressed after birth in the ovary in the granulosa cells of healthy, small growing follicles. We have shown that AMH affects two important regulatory steps during folliculogenesis. At initial recruitment, AMH inhibits recruitment of primordial follicles into the growing pool, while at cyclic recruitment AMH lowers the FSH-sensitivity of follicles. In these ways, AMH plays an important role in regulation of ovarian follicle growth. AMH serum level is a strong candidate marker for ovarian reserve in women. In normo-ovulatory women, AMH serum levels correlated strongly with the number of antral follicles. In addition, AMH is a strong predictor for the number of oocytes retrieved in patients undergoing IVF treatment. The convenience of determination and its relative stable expression during the menstrual cycle indicate that further validation of the use of serum AMH is recommended as a clinical measure of ovarian reserve.
Adult↗
Female mice carrying a ubiquitin promoter-Insl3 transgene have descended ovaries and inguinal hernias but normal fertility.
Mouse knockout studies have indicated that Insl3 is involved in development of the gubernaculum in males, which is essential for normal testicular descent. To determine further the functions of Insl3 we have generated transgenic (TG) mice ubiquitously expressing Insl3. In these mice low levels of transgenic Insl3 mRNA are expressed in all tissues analyzed. In the TG females the ovaries descend to the base of the abdominal cavity during the fetal period, as a consequence of the formation of male-like gubernaculum structures. Furthermore, the gubernacular structures developed express androgen receptor, identically to the corresponding structures in males. At adult age the ligaments formed connect the uterine horns to the inguinal region of the abdomen. Ligaments are also formed between the lower and upper parts of the uterine horns, and these ligaments force the uterus to form a coiled structure. However, the TG females retain their reproductive functions, indicating that neither the location of the ovaries nor the macroscopic structure of the uterus is vital for reproduction. In addition, Insl3 expression causes inguinal hernia in females, suggesting that a combination of estrogen and Insl3 action disrupts proper development of the muscular and connective tissue structures of the abdomen. The lack of a phenotype in other tissues indicates that gubernaculum formation is the most sensitive biological response as regards Insl3.
Animals↗