Biomedical subjects

P Pakarinen

Publications and source records attributed to P Pakarinen.

At least 19 recordsLinked to original sources

PubMed2003

Effects of levonorgestrel-releasing intra-uterine system on the expression of vascular endothelial growth factor and adrenomedullin in the endometrium in adenomyosis.

BACKGROUND: The levonorgestrel-releasing intra-uterine system (LNg-IUS) has been used to control menorrhagia, but irregular bleeding during the first 3 months of use was the most notable side effect. Endometrial angiogenesis is believed to be regulated by angiogenic factors. The study aim was to evaluate the effects of LNg-IUS on vascular endothelial growth factor (VEGF) and adrenomedullin (AM) expression in the endometrium. METHODS: VEGF and AM expression were analysed using the avidin-biotin immunoperoxidase method on endometrial curettage specimens from menorrhagic women associated with adenomyosis before and 3 months after LNg-IUS insertion. RESULTS: VEGF expression was abundant both in the endometrial glands and stroma before LNg-IUS insertion, but became scanty 3 months after insertion. No immunostaining for AM was noted in the endometrial glands and stroma before LNg-IUS insertion, whereas AM immunostaining became prominent in the endometrial glands and stroma 3 months after LNg-IUS use. CONCLUSIONS: This is the first study to demonstrate that LNg-IUS insertion results in decreased expression of VEGF and increased expression of AM in the endometrial glands and stroma after 3 months of use. The results obtained suggest that the increase in AM expression in the endometrium may be responsible for the frequent occurrence of irregular bleeding during the initial 3 months of LNg-IUS use.

Adrenomedullin↗

PubMed2003

Age-related uterine and ovarian hypertrophy in FSH receptor knockout and FSHbeta subunit knockout mice.

Female mice in which the gene encoding the follicle-stimulating hormone FSH receptor (FSHR) knockout (KO) or its ligand (FSHbetaKO) have been disrupted were infertile. Ovaries of these mice were significantly smaller than those of heterozygous littermates but significantly larger than those of hypogonadal mice of the same age. Uterine masses in all three mutants were <6 mg, significantly reduced compared with heterozygous mice. At 1 year of age uterine mass had increased to >12 mg in 63% of FSHRKO females and 88% of FSHbetaKO females. Despite the increase in uterine size there was no evidence of contractility: uteri were flaccid and unresponsive to electrical or pharmacological stimulation. In most females in which uterine growth had occurred there was evidence of ovarian growth with hypertrophy of the interstitial tissue, occurrence of ovarian cysts and epithelial and tubular inclusions. There was no evidence of uterine or ovarian hypertrophy in hypogonadal (hpg) mice at any age or in 1 year old females in which the FSH mutations were bred onto the hpg background. There was an inverse correlation of plasma LH concentrations and uterine mass in 1 year old mutant females with uterine hypertrophy. Ovariectomy of both FSHRKO and FSHbetaKO females with large uteri resulted in decreased uterine mass and increased plasma concentration of LH. The number of mice with ovarian pathology, reminiscent of the serous ovarian adenocarcinomas found in humans, was significantly greater in the FSHbetaKO mice, indicating that the presence of an intact FSH receptor on ovarian cells of FSHbetaKO females may allow constitutive basal stimulation of the ovary, which is absent in mice lacking FSH receptors.

Aging↗

PubMed2002

Lack of association of the common immunologically anomalous LH with endometriosis.

BACKGROUND: Subfertile women with endometriosis have been reported to demonstrate impaired follicular growth, ovulatory dysfunction and disturbed LH patterns. In addition, abnormal LH and/or LH receptors have been linked with endometriosis-associated infertility. Carriers of a variant of the beta-subunit of luteinizing hormone (V-LH) are largely healthy; however, differences in their gonadal function such as alterations in gonadal steroidogenesis, ovarian reserve, pubertal development and predisposition to diseases such as infertility and polycystic ovarian disease have been found. METHODS AND RESULTS: To explore the possible relationship between endometriosis and V-LH, we examined its frequency in 230 women undergoing laparoscopic surgery for the investigation of infertility. For the entire study population, 185 (80.4%) were wild type; 42 (18.3%) were heterozygous; and three (1.3%) were homozygous for V-LH. No difference was found between women with (n = 85) and without (n = 145) endometriosis concerning the frequency of the type of LH. CONCLUSION: Our results do not support the hypothesis that the variant form of LH is associated with an altered risk of endometriosis in the population tested.

Adult↗

PubMed2002

How much LH do the Leydig cells see?

The purpose of this study was to assess the concentrations of LH that Leydig cells are exposed to upon in vivo stimulation of steroidogenesis. The concentrations of LH were measured in rats in testicular interstitial extracellular fluid, seminiferous tubular fluid and blood plasma from testicular veins from one testis before and from the other testis of the same rats after an intravenous injection of gonadotrophin-releasing hormone (GnRH) or saline, and compared with the concentrations in blood plasma from a peripheral vein. The concentrations of LH in interstitial fluid surrounding the Leydig cells before the injections were about 10% of the levels in blood plasma, and showed no significant rise at 15 min and a much smaller rise at later times in rats injected with GnRH than those seen in blood plasma from either of the two sources, which were similar. The concentrations of LH in tubular fluid were even lower and showed no change after GnRH. Testosterone concentrations in testicular cells, interstitial fluid and testicular venous blood plasma were significantly increased by 15 min after GnRH, when compared with saline-injected controls, with no change in the levels in tubular fluid. The rise in testosterone concentrations in testicular venous plasma after GnRH was smaller than those in the cells and interstitial fluid. In conclusion, the concentrations of LH reaching the testicular interstitial fluid were only about one-tenth of that measured in the circulation, presumably because the endothelial cells restrict access of the hormone to the interstitial fluid. This indicated that either the Leydig cells are extremely sensitive to LH stimulation or that testicular endothelial cells modulate the action of LH on the Leydig cells.

Animals↗

PubMed2001

Progestin-releasing intrauterine systems.

The levonorgestrel-releasing intrauterine system (LNG IUS) is an effective method for contraception. It has a strong antiproliferative action on the endometrium. The endometrium is transformed under the influence of local levonorgestrel and becomes unresponsive to ovarian estrogens. This process is associated with progressive reduction of menstrual blood loss and menstrual duration. Scanty and irregular bleeding and/or spotting is usual during the first 3 to 4 months. The reduction of menstrual blood loss continues and after the first 9 months many women have no bleeding at all. However, they have normal ovarian function. The absence of bleeding is a result of the local antiproliferative action of the LNG IUS on the endometrium, which is also responsible for many health benefits during the use of this method. As with oral contraceptives, the risk of pelvic inflammatory disease is reduced, because of reduced menstrual blood loss, endometrial suppression, and thickening of the cervical mucus. There are some steroidal side effects: mood changes, oily skin, and acne. Weight increase is similar to that associated with copper intrauterine devices: 500 g per year over 5 years. Users should be told that the LNG IUS does not prevent sexually transmitted infection, and therefore women at risk should also use condoms for their protection.

Acne Vulgaris↗

PubMed2001

Therapeutic use of the LNG IUS, and counseling.

The intrauterine release of levonorgestrel (LNG) alters the function of the endometrium. This phenomenon offers special health benefits for users and a manner of local intrauterine therapy. In this review we discuss use of LNG-releasing intrauterine system (LNG IUS) in treatment and prevention of anemia and in the therapy of menorrhagia and dysmenorrhea. The antiproliferative effect of the LNG IUS on the endometrium offers targeted therapy against the proliferative action of estrogen on the endometrium during hormone replacement therapy. The LNG IUS as an alternative to sterilization is also discussed. There are also promising therapeutic fields such as use of the LNG IUS in the treatment of endometriosis and in the protection of endometrium exposed to tamoxifen during breast cancer treatment. Special attention is paid to counseling because successful use of the LNG IUS requires good training of the providers and extensive counseling of users.

Anemia↗

PubMed2001

Effects of the levonorgestrel-releasing intrauterine system on proliferation and apoptosis in the endometrium.

BACKGROUND: The levonorgestrel-releasing intrauterine system (LNg-IUS) has been shown to be effective in the management of menorrhagia. In order to evaluate the effects of LNg-IUS on endometrial proliferation and apoptosis, proliferating cell nuclear antigen (PCNA) expression, apoptosis, Fas and Bcl-2 protein expression in the endometrium were determined at the early proliferative phase of the menstrual cycle before and 3 months after LNg-IUS insertion. METHODS: PCNA, Fas and Bcl-2 protein expression were analysed using an avidin-biotin immunoperoxidase method. Apoptosis was assessed by the terminal deoxynucleotidyl transferase-mediated deoxy-UTP nick-end labelling (TUNEL) method. RESULTS: PCNA, immunolocalized both in the nuclei of endometrial glands and stroma was less abundant 3 months after insertion (P < 0.05). Bcl-2 protein, immunolocalized in the cytoplasm of endometrial glands but not in the stroma, became scanty 3 months after insertion. Fas antigen, immunolocalized only in endometrial glands before insertion, became prominent in both endometrial glands and stroma 3 months after insertion. The apoptosis-positive rate of the nuclei in both endometrial glands and stroma was significantly higher 3 months after insertion relative to that before insertion (P < 0.05). CONCLUSIONS: LNg-IUS resulted in a decrease in endometrial proliferation and an increase in apoptosis in endometrial glands and stroma. The increase in apoptosis associated with increased Fas antigen expression and decreased Bcl-2 protein expression in the endometrium may be one of the underlying molecular mechanisms by which LNg-IUS insertion causes the atrophic change of the endometrium.

Adult↗

PubMed2001

Assessment of mechanisms of thyroid hormone action in mouse Leydig cells: regulation of the steroidogenic acute regulatory protein, steroidogenesis, and luteinizing hormone receptor function.

Recently, we demonstrated that triiodothyronine (T(3)) stimulated steroid hormone biosynthesis and steroidogenic acute regulatory (StAR) protein expression in mLTC-1 mouse Leydig tumor cells through the mediation of steroidogenic factor 1 (SF-1). We now report a dual response mechanism of T(3) on steroidogenesis and StAR expression, and on LH receptor (LHR) expression and binding in mLTC-1 cells. T(3) acutely (8 h), induced a 260% increase in StAR messenger RNA (mRNA) expression over the basal level which was coincident with an increase in progesterone (P) production. In contrast, chronic stimulation with T(3) (beyond 8 h), resulted in an attenuation of StAR expression and P production. This attenuation was most likely caused by a decrease in cholesterol delivery to the inner mitochondrial membrane as demonstrated by incubations with the hydrophilic steroid precursors, 22R hydroxycholesterol and pregnenolone, which restored P synthesis. In similar studies, chronic treatment with T(3) increased the levels of cytochrome P450scc mRNA by 83%, whereas those of cytochrome P450 17alpha-hydroxylase and 3ss-hydroxysteroid dehydrogenase decreased. The diminished response in steroidogenesis following chronic T(3) exposure was not a result of alterations in StAR mRNA stability, but rather was due to inhibition of transcription of the StAR gene. Similar acute stimulatory and chronic inhibitory responses to T(3) were found when LHR mRNA expression and LHR ligand binding were examined. Transfections with an LHR or StAR promoter/luciferase reporter construct demonstrated that a 173-bp fragment of the LHR promoter containing an SF-1 binding motif was involved in T(3) response, as was the SF-1 recognition site at -135 bp in the StAR promoter. Furthermore, the importance of SF-1 in T(3) function was also verified employing mutation in the bases of SF-1 sequences using electrophoretic mobility shift assays. The potential physiological relevance of these findings was demonstrated when similar responses were obtained in mice rendered hypo and hyperthyroid. Collectively, these observations further characterize the thyroid-gonadal connection and provide insights into the mechanisms for a dual regulatory role of thyroid hormone in Leydig cell functions.

3-Hydroxysteroid Dehydrogenases↗

PubMed1999

A common polymorphic allele of the human luteinizing hormone beta-subunit gene: additional mutations and differential function of the promoter sequence.

A common genetic variant (V) of the human luteinizing hormone (LH) beta-subunit gene was recently discovered. The V-LH molecules have higher bioactivity in vitro, but shorter half-life in circulation, which apparently is related to the alterations of LH function observed in individuals homo- and heterozygous for the V-LHbeta allele. We have now studied whether additional mutations in the V-LHbeta promoter sequence could contribute to the altered physiology of the LH variant molecules. The 661 bp 5'-flanking region of the V-LHbeta gene, retrieved from human genomic DNA by PCR, contained eight single-nucleotide changes, as compared with the wild-type (wt) LHbeta promoter. The finding was consistent in DNA samples of different ethnic groups. Reporter constructs with various lengths of the wt- and V-LH promoter sequences, driving the firefly luciferase reporter gene, were transfected into an immortalized mouse pituitary cell line, LbetaT(2), known to express the endogenous LHbeta gene, and into a non-endocrine human embryonic kidney cell line, HEK 293. Basal expression levels of the V-LHbeta promoter constructs were on average 36% higher in LbetaT(2)cells ( P < 0.001; n = 29), and 40% higher in HEK 293 cells ( P < 0.001; n = 16), as compared with the respective wt sequences. Numerous qualitative and quantitative differences were found between the two cell lines in responses of the two promoter sequences to stimulation with 12- O -tetradecanoylphorbol-13-acetate, forskolin, 8-bromo-cAMP, progesterone and gonado- tropin-releasing hormone. In conclusion, the V-LHbeta promoter has higher basal activity, and differs in response to hormonal stimulation, as compared with the wt-LHbeta promoter. The altered promoter function of the V-LHbeta gene provides evidence for differences in regulation of the wt- and V-LHbeta genes, which may contribute to the differences observed in pituitary-gonadal function between carriers of the two LHbeta alleles. The findings also suggest a novel evolutionary mechanism whereby polymorphic changes resulting in altered bioactivity of a gene product may be compensated for by additional mutations in the cognate promoter sequence, changing transcription of the same gene.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed1999

Functional assessment of the calcium messenger system in cultured mouse Leydig tumor cells: regulation of human chorionic gonadotropin-induced expression of the steroidogenic acute regulatory protein.

The steroidogenic acute regulatory (StAR) protein, a 30-kDa mitochondrial factor, is a key regulator of steroid hormone biosynthesis, facilitating the transfer of cholesterol from the outer to the inner mitochondrial membrane. StAR protein expression is restricted to steroidogenic tissues, and it responds to hormonal stimulation through different second messenger pathways. The present study was designed to explore the mechanisms of extracellular calcium (Ca2+) involved in the hCG-stimulated expression of StAR protein and steroidogenesis in a mouse Leydig tumor cell line (mLTC-1). Extracellular Ca2+ (1.5 mmol/liter) enhanced the hCG (50 microg/liter)-induced increases in StAR messenger RNA (mRNA) and protein levels (1.7 +/- 0.3-fold; 4 h), as monitored by quantitative RT-PCR and immunoblotting. The potentiating effect of Ca2+ on the hCG-stimulated StAR response correlated with the acute progesterone (P) response. In accordance, omission of Ca2+ from the extracellular medium by specific Ca2+ chelators, EDTA or EGTA (4 mmol/liter each), markedly diminished the hCG-stimulated P production. The Ca2+ effect on hCG-induced StAR mRNA expression was dramatically suppressed by 10 micromol/liter verapamil, a Ca2+ channel blocker. The Ca2+-mobilizing agonist, potassium (K+; 4 mmol/liter), greatly increased the hCG responses of StAR expression and P production, which conversely were attenuated by Ca2+ antagonists, further supporting the involvement of intracellular free Ca2+ ([Ca2+]i) in these responses. The interaction of Ca2+ or K+ with hCG accounted for a clear increase in the StAR protein level (1.4-1.8-fold; 4 h) compared with that after hCG stimulation. Inhibition of protein synthesis by cycloheximide (CHX) drastically diminished the hCG-induced StAR protein content, indicating the requirement for on-going protein synthesis for hCG action. The transmembrane uptake of 45Ca2+ was increased by 26% with hCG and was strongly inhibited by verapamil. [Ca2+]i moderately augmented the response to hCG in fura-2/AM-loaded mLTC-1 cells within 30-40 sec, reaching a plateau within 1-3 min. Interestingly, the calcium ionophore (A23187) clearly increased (P < 0.01) StAR mRNA expression, in additive fashion with hCG. Northern hybridization analysis revealed four StAR transcripts at 3.4, 2.7, 1.6, and 1.4 kb, with the 1.6-kb band corresponding to the functional StAR protein; all of them were up-regulated 3- to 5-fold upon hCG stimulation, with a further increase in the presence of Ca2+. The mechanism of the Ca2+ effect on hCG-stimulated StAR expression and P production was evaluated by assessing the involvement of the nuclear orphan receptor, steroidogenic factor 1 (SF-1). Stimulation of hCG significantly elevated (2.1 +/- 0.3-fold) the SF-1 mRNA level, which was further augmented in the presence of Ca2+, whereas EGTA and verapamil completely abolished the increase caused by Ca2+. Cells expressing SF-1 marginally increased StAR expression, but coordinately elevated StAR mRNA levels in response to hCG and hCG plus Ca2+ compared with those in mock-transfected cells. On the other hand, overexpression of the nuclear receptor DAX-1 remarkably diminished (P < 0.0001) the endogenous SF-1 mRNA level as well as hCG-induced StAR mRNA expression. In summary, our results provide evidence that extracellular Ca2+ rapidly increases [Ca2+]i after hCG stimulation, presumably through opening of the transmembrane Ca2+ channel. Neither extracellular Ca2+ nor K+ alone has a noticeable effect on StAR expression and steroidogenesis, whereas they clearly potentiate hCG induction. The Ca2+-mediated increase in hCG involved in StAR expression and P production is well correlated to the levels of SF-1 expression. The stimulatory effect of hCG that rapidly increases [Ca2+]i is responsible at least in part for the regulation of SF-1-mediated StAR expression that consequently regulates steroidogenesis in mouse Leydig tumor cells.

Animals↗

PubMed1999

The effect of intrauterine and oral levonorgestrel administration on serum concentrations of sex hormone-binding globulin, insulin and insulin-like growth factor binding protein-1.

BACKGROUND: The concentrations of sex hormone-binding globulin (SHBG) have been shown to decrease during the use of levonorgestrel (LNG)-containing contraception. This decrease has been thought to be due to the androgenic action of LNG. In endogenously hyperandrogenic women, particularly in those with increased body weight, serum SHBG correlates with circulating insulin-like growth factor binding protein-1 (IGFBP-1) concentration, and both are inversely related to insulin. LNG-containing combined contraceptives have also been reported to increase the pancreatic insulin secretion. OBJECTIVE: To examine whether serum insulin and IGFBP-1 levels are related to SHBG during the use of intrauterine or oral levonorgestrel contraception. METHODS: Thirty-one fertile women were divided into three study groups: A copper-releasing intrauterine device (IUD) was inserted in control group (n= 10), and the LNG-releasing intrauterine contraceptive system (LNG-IUS) in group II (n= 10), and 30 mirog LNG-containing contraceptive minipills were given in group III (n=11). Twenty-nine women completed the study and one woman was excluded because of a high body mass index. Fasting concentrations of blood glucose, insulin, SHBG, IGFBP-1, testosterone and LNG before and after three-months-use of contraception were measured. RESULTS: SHBG concentrations decreased slightly during oral LNG contraception, but not during the use of the LNG-IUS. No change was found in blood glucose, serum insulin, serum IGFBP-1 and serum total testosterone concentrations in either group. In our study group, including women with normal body weight, no correlation was detected between insulin and SHBG concentrations before or after LNG contraception, whereas an inverse correlation was found between insulin and IGFBP-1 levels at the baseline as well as after LNG-IUS use (R2= 0.578; p=0.001). Multiple regression analysis showed no significant association between the levels of SHBG and IGFBP-1 as dependent factors, and glucose, insulin, LNG, age, waist-hip ratio and body mass index as dependent factors. CONCLUSIONS: Our data imply that the effect of levonorgestrel on variables associated with endogenous hyperandrogenism remains borderline in women with normal body mass index.

Adult↗

PubMed1998

The effect of intrauterine levonorgestrel use on the expression of c-JUN, oestrogen receptors, progesterone receptors and Ki-67 in human endometrium.

The major regulators of endometrial function are oestrogen and progesterone, which act through binding their nuclear receptors and by activating transcription of their target genes. Interactions between steroid receptors and transcription proteins, e.g. c-JUN/AP-1, can modulate steroid action at the transcriptional level. The 19-nortestosterone-derived progestin, levonorgestrel, is used for contraception, treatment of menorrhagia and for endometrial protection during hormone replacement therapy, but the signalling pathways of its action are totally undefined. We examined the effect of an intrauterine system, releasing 20 microg of levonorgestrel per 24 h (LNG-IUS), on immunoreactive oestrogen receptor, progesterone receptor, c-JUN and Ki-67 expression in 29 endometrial specimens, obtained from fertile women using the LNG-IUS for contraception. Moderate to strong immunostaining for oestrogen receptors was observed in the stromal cells in all specimens, in glandular epithelial cells in 26 cases and in flattened luminal epithelial cells in 17 specimens. Decidualized stromal cells showed no progesterone receptor immunoreactivity in 19 of the 29 specimens, and weak to moderate immunostaining in 10 cases. Luminal epithelial cells were negative for progesterone receptor in all samples. Intense nuclear staining for C-JUN was observed in epithelial cells in 26 and in decidualized stromal cells in all 29 of the samples. In 16 samples, Ki-67 immunoreactivity was evaluated as weak to moderate in decidualized stroma, and in 13 samples absent. Our data demonstrate that intrauterine release of LNG maintains constant expression of C-JUN and exerts progestational effects in the endometrium in the absence of progesterone receptors. In contrast, LNG-IUS inhibits several cellular responses to oestrogen despite the presence of endogenous oestrogen and oestrogen receptors. These data suggest that the progestational effects induced by progesterone and levonorgestrel are mediated through different signalling pathways.

Adult↗

PubMed1998

Gonadotropin-independent regulation of steroidogenesis in the fetal rat testis.

UNLABELLED: The goal of the present study was to determine whether the onset of fetal Leydig cell steroidogenesis is dependent on gonadotropic stimulation. The relationships between the onset of pituitary LH synthesis and secretion, and the response of testicular steroidogenesis to LH and various putative paracrine factors were examined. We found by reverse transcription-polymerase chain reaction (RT-PCR) that the LHbeta-subunit gene expression in the fetal pituitary gland starts on embryonic day (E) 16.5. Plasma LH was very low (< 5.0 ng/L) until E19.5 and increased significantly thereafter. In contrast, the greatest increase in the testicular testosterone had already occurred between E18.5 and E19.5. Hence, fetal testicular steroidogenesis must start independent of LH stimulation. Basal testosterone production in incubations of fetal testis (E16.5-19.5) was high, 50-80% of the hCG-stimulated level. In contrast, in dispersed fetal Leydig cells, basal steroidogenesis was consistently low. This suggests the presence of paracrine factors in the intact testes that stimulate their steroidogenesis. Effects of various putative paracrine factors were thereafter tested on the fetal testis. We found for the first time that both vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activating polypeptide (PACAP-27) markedly stimulated fetal, but not adult, Leydig cells. IN CONCLUSION: 1) Pituitary LH cannot be the initial stimulus for fetal testicular steroidogenesis. 2) Some paracrine factor(s) probably turn on and maintain early fetal testicular steroidogenesis before the later onset of LH secretion, although a constitutive component in the onset of steroidogenesis is also possible. 3) VIP and PACAP-27 are likely candidates for a paracrine stimulus of the fetal testis.

Animals↗

PubMed1998

The frequency of an inactivating point mutation (566C-->T) of the human follicle-stimulating hormone receptor gene in four populations using allele-specific hybridization and time-resolved fluorometry.

We have described previously in the Finnish population an inactivating point mutation (566C-->T) in the human FSH receptor (FSHR) gene. In women, this mutation causes hypergonadotropic ovarian failure with arrest of follicular maturation and infertility, whereas in men, there is variable suppression of spermatogenesis, but no absolute infertility. To determine whether the same FSHR mutation occurs in other populations, its frequency was determined in Finland, Switzerland, Denmark, and the Chinese population of Singapore. The mutation was screened for using genomic DNA extracted from whole blood or dried blood spots. Exon 7 of the FSHR gene was first amplified using a pair of biotinylated primers. The PCR products were then immobilized on streptavidin-coated microtitration wells and hybridized using short allele-specific oligonucleotide probes labeled with europium. Time-resolved fluorometry was used for europium signal detection. To test the reliability of this method, 40 isolated DNA samples and 35 dried blood spot samples were blindly tested for the 566C-->T FSHR mutation. The analyses yielded identical results with denaturing gradient gel electrophoresis and allele-specific restriction enzyme digestion of the same samples, thus demonstrating the reliability of the tested method. Automation of this procedure allows the screening of large numbers of samples, which was subsequently carried out to investigate the frequency of the 566C-->T mutation in the study populations. A total of 4981 samples from the above-mentioned 4 countries were analyzed. The frequency of the 566C-->T mutation was 0.96% for all Finnish samples (n=1976), with a strong enrichment of the mutant allele in the northeastern part of the country. Only 1 mutation carrier was identified in the samples from Switzerland (n=1162), whereas none was found in samples from Denmark (n=1094) and the Singapore Chinese (n=540). These results suggest that the 566C-->T mutation of the FSHR gene is enriched in Finland, but is uncommon in other populations.

Alleles↗

PubMed1996

A 12-month comparative clinical investigation of a levonorgestrel-releasing intracervical device situated in the uterine cavity or cervical canal.

A randomized study was performed in two clinics in order to compare the efficacy, safety and acceptability of a new model of a levonorgestrel-releasing intracervical device situated either in the cervical canal (group I) or in the uterine cavity (group II). Group I included 151 women (age 18-43) and group II, 147 women (age 19-43). The number of nulliparous women was 145. The total expulsion rate was 9.1%. The expulsion rate was lower among nulliparous women (4.8%) than among parous women (13.1%). There was also a significant difference in the expulsion rates between the two clinics. Two pregnancies occurred in both groups and two of these were ectopic, one in each group. The other two occurred after unnoticed expulsion. These figures give 12-month cumulative pregnancy rates of 1.3% and 1.4% in groups I and II, respectively. Total infection rate was 0.3%. The continuation rates were 82.1% in group I and 85.0% in group II after the first year. At three-month follow-up there were significantly fewer menstrual problems in group I than in group II (p = 0.0266). It is concluded that expulsion is still a problem with a small device but it may be diminished by intrauterine insertion and by selecting the users carefully.

Adolescent↗

PubMed1996

A case of hypergonadotrophinaemia associated with very high isolated concentrations of immunologically and biologically active luteinizing hormone.

A very rare case of a menstruating infertile woman with isolated luteinizing hormone (LH) hypergonadotrophinaemia is presented. There were no signs indicating the presence of a pituitary microadenoma, and LH had normal bioactivity and normal molecular weight. Likewise, no mutation was detected in the coding region of the LH beta-chain gene. In a non-stimulated cycle and a clomiphene citrate cycle, the patient developed an unruptured cyst. The patient ovulated and conceived twice following the addition of human chorionic gonadotrophin. A partial resistance at the ovarian LH receptor site, perhaps caused by a mutation, is a possible explanation for these findings. Another possibility is a malfunction in the signal transduction system of LH beyond the receptor level.

Adult↗

PubMed1995

Mutation in the follicle-stimulating hormone receptor gene causes hereditary hypergonadotropic ovarian failure.

Hypergonadotropic ovarian dysgenesis (ODG) with normal karyotype is a heterogeneous condition that in some cases displays Mendelian recessive inheritance. By systematically searching for linkage in multiplex affected families, we mapped a locus for ODG to chromosome 2p. As the previously cloned follicle-stimulating hormone receptor (FSHR) gene had been assigned to 2p, we searched it for mutations. A C566T transition in exon 7 of FSHR predicting an Ala to Val substitution at residue 189 in the extracellular ligand-binding domain segregated perfectly with the disease phenotype. Expression of the gene in transfected cells demonstrated a dramatic reduction of binding capacity and signal transduction, but apparently normal ligand-binding affinity of the mutated receptor. We conclude that the mutation causes ODG in these families.

Base Sequence↗

PubMed1995

The effect of local intrauterine levonorgestrel administration on endometrial thickness and uterine blood circulation.

To evaluate non-invasively the role of levonorgestrel releasing devices in direct contact with the endometrium on menstrual spotting and endometrium inactivation, we inserted levonorgestrel releasing devices (20 micrograms/24 h) either into the cervical canal or the uterine cavity of 30 fertile women. Both before insertion and over the following 3 months, we used transvaginal sonography to measure the endometrial thickness in 20 of the women and Doppler flow to measure the uterine blood flow in the remaining 10 women. The women were asked to keep records of menstrual bleeding and they gave blood samples for the measurement of serum oestradiol, progesterone and levonorgestrel. By 10 weeks after insertion there was a significant decrease in endometrial thickness in both groups. Intracervical levonorgestrel release allowed the endometrium to maintain cyclic changes, whereas direct intrauterine levonorgestrel release eliminated the cyclical changes. The total number of spotting days was significantly less (P = 0.0249) in the intracervical release group at 3 months; 1.2 +/- 0.6 versus 8.1 +/- 1.8 (mean +/- SE). There were no significant differences in hormone concentrations between the groups. The pulsatility index did not change significantly during the study. We concluded that the inactivation process of the endometrium can be monitored by transvaginal sonography and that locally administered levonorgestrel does not change circulatory conditions detectable by Doppler flow. Our results also suggest that the inactivation process of the endometrium is different between intracervical and intrauterine levonorgestrel administration and may explain the difference in the number of spotting days.

Adult↗