C-Peptide, Baseline and Postprandial Insulin Resistance after a Carbohydrate-Rich Test Meal - Evidence for an Increased Insulin Clearance in PCOS Patients?

Introduction Known characteristics of patients with PCOS include infertility, menstrual disorders, hirsutism and also often insulin resistance. These symptoms increase with increasing body weight. In the LIPCOS study (Lifestyle Intervention for Patients with Polycystic Ovary Syndrome [PCOS]) long-term changes of the PCOS in dependence on pregnancy and parenthood were systematically assessed. In the framework of the LIPCOS study, PCOS patients were given a standardised carbohydrate-rich test meal in order to examine glucose homeostasis and insulin secretion. The results were compared with those of a eumenorrhoeic control group who all had corresponding BMI values and corresponding ages. Methods and Patients 41 PCOS patients (without diabetes) and 68 controls received a standardised carbohydrate-rich test meal (260 kcal, 62 % carbohydrates, 32 % fat, 6 % proteins) in order to generate a submaximal insulin and glucose stimulation. The values were determined at baseline and postprandial after 60, 120 and 180 minutes. In addition, the corresponding C-peptide levels were recorded. Results In the PCOS patients (n = 41), the insulin secretion test after a standardised test meal showed almost identical baseline and postprandial insulin levels when compared with those of the age- and BMI-matched eumenorrhoeic controls (n = 68). In the PCOS patients, the baseline and postprandial glucose levels were significantly elevated (92.88 ± 10.28 [PCOS] vs. 85.07 ± 9.42 mg/dL [controls]; p < 0.001) so was C-peptide (p < 0.025). Conclusions In the present study we have shown for the first time that, after consumption of a standardised test meal, PCOS patients formally exhibit a higher fasting insulin resistance than controls. In spite of the higher stimulated C-peptide levels, the insulin levels did not increase more strongly with increasing glucose levels than in controls which may be indicative of a higher insulin clearance in PCOS patients.

Identification of an ovarian voltage-activated Na+-channel type: hints to involvement in luteolysis.

An endocrine type of voltage-activated sodium channel (eNaCh) was identified in the human ovary and human luteinized granulosa cells (GC). Whole-cell patch-clamp studies showed that the eNaCh in GC is functional and tetrodotoxin (TTX) sensitive. The luteotrophic hormone human CG (hCG) was found to decrease the peak amplitude of the sodium current within seconds. Treatment with hCG for 24-48 h suppressed not only eNaCh mRNA levels, but also mean Na+ peak currents and resting membrane potentials. An unexpected role for eNaChs in regulating cell morphology and function was indicated after pharmacological modulation of presumed eNaCh steady-state activity in GC cultures for 24-48 h using TTX (NaCh blocker) and veratridine (NaCh activator). TTX preserved a highly differentiated cellular phenotype. Veratridine not only increased the number of secondary lysosomes but also led to a significantly reduced progesterone production. Importantly, endocrine cells of the nonhuman primate corpus luteum (CL), which represent in vivo counterparts of luteinized GC, also contain eNaCh mRNA. Although the mechanism of channel activity under physiological conditions is not clear, it may include persistent Na+ currents. As observed in GC in culture, abundant secondary lysosomes were particularly evident in the regressing CL, suggesting a functional link between eNaCh activity and this form of cellular regression in vivo. Our results identify eNaCh in ovarian endocrine cells and demonstrate that their expression is under the inhibitory control of hCG. Activation of eNaChs in luteal cells, due to loss of gonadotropin support, may initiate a cascade of events leading to decreased CL function, a process that involves lysosomal activation and autophagy. These results imply that ovarian eNaChs are involved in the physiological demise of the temporary endocrine organ CL in the primate ovary during the menstrual cycle. Because commonly used drugs, including phenytoin, target NaChs, these results may be of clinical relevance.

Presence of transforming growth factor alpha and epidermal growth factor in human ovarian tissue and follicular fluid.

Intra-ovarian regulation of follicular maturation is modulated by various factors. Among these, growth factors are important local actors. We examined the immunohistochemical localization of transforming growth factor alpha (TGF-alpha), epidermal growth factor (EGF) and epidermal growth factor receptor (EGF-R) in 18 human ovaries. The concentration of TGF-alpha and EGF in follicular fluid was measured by ELISA. TGF-alpha was detected in oocytes of primordial and early preantral follicles. Furthermore, staining was observed in granulosa cells of preantral follicles and in theca cells of preantral, antral and preovulatory follicles. EGF showed a similar distribution as TGF-alpha. Atretic follicles were strongly positive for TGF-alpha and EGF. In the corpus luteum, theca lutein cells were strongly positive for TGF-alpha and EGF. Immunoreactivity for EGF-R was observed only in the granulosa cells of antral follicles. Follicular fluids from patients undergoing in-vitro fertilization (IVF) were examined for their content of TGF-alpha and EGF. TGF-alpha was detected in 37% of the samples. The concentration ranged from 43 pg/ml to 602 pg/ml. EGF was not detected in any of the follicular fluids tested. These observations support the participation of EGF/TGF-alpha in follicular maturation. Furthermore, the presence of TGF-alpha in follicular fluid and the simultaneous absence of EGF suggests that TGF-alpha plays a more pronounced role than EGF in oocyte maturation during late follicular phase.

Effect of motile sperm count after swim-up on outcome of intrauterine insemination.

OBJECTIVE: To analyze the prognostic value of motile sperm count after swim-up in IUI with husband's sperm in a large group of subfertile couples. DESIGN: Retrospective study. SETTING: University hospital. PATIENT(S): Nine hundred two couples undergoing 3,037 treatment cycles. INTERVENTION(S): Intrauterine insemination with husband's sperm after swim-up was performed after mild ovarian stimulation with clomiphene citrate and hCG under hormonal and ultrasonographic control of follicle development. MAIN OUTCOME MEASURE(S): Pregnancy rate (PR) in correlation to motile sperm count after swim-up. RESULT(S): A nonlinear increase in PR per treatment cycle was observed with increasing numbers of motile sperm used for IUI. Insemination with < 0.8 x 10(6) motile sperm after swim-up resulted in a PR of < 1% per treatment cycle. When the motile sperm count was above this level, the PR per cycle reached a plateau of 6.9% to 10.2%, with a minor tendency for increase with higher sperm numbers. CONCLUSION(S): Strict analysis of motile sperm count after swim-up is a useful prognostic factor for PRs after IUI. There is a good chance for conception if > or = 0.8 x 10(6) motile sperm are available after appropriate selection methods. Intrauterine insemination performed with considerably higher numbers of motile sperm does not lead to a significant increase in PRs.

Sperm acrosome antigen-1, a molecule intimately involved in the regulation of the acrosome reaction: analysis of expression on spermatozoa from infertile couples.

Sperm acrosome antigen-1 (SAA-1) is a molecule on the acrosomal cap of sperm from the human and a number of mammalian and lower species. SAA-1 was initially characterized by a monoclonal antibody (mab) AG7 directed against SAA-1. Previous studies indicate that SAA-1 may play an important role in the regulation of the acrosome reaction in the human and other species. Unselected couples seeking infertility treatment were subjected to an analysis of the amount of SAA-1 present on washed husband sperm. Using indirect immunofluorescence as well as radioimmunobinding assay, the expression of SAA-1 on patient spermatozoa was found to be significantly decreased compared to a group of healthy sperm donors. The decrease in SAA-1 did not correlate well with sperm morphology. Couples entered into the study were followed for an average of 12 months, while they received infertility treatment. Most couples conceived after a variable number of treatment cycles. It is concluded that a decrease of SAA-1 expression may contribute to subfertility, which can be overcome by the aid of assisted reproduction.

[Idiopathic subfertility: pregnancy rate after IVF treatment in minimally stimulated monofollicular ovarian cycle]. / Idiopathische Subfertilität: Schwangerschaftsraten nach IVF-Behandlung im minimal stimulierten monofollikulären Ovarialzyklus.

Fifty-nine patients with idiopathic subfertility were treated with IVF in 176 minimally stimulated cycles. Twenty pregnancies were achieved, resulting in pregnancy rates of 11.4% per treatment cycle and 21.3% per embryo transfer. Thus, the mode of treatment described here appears to be an useful alternative to IVF or laparoscopic GIFT in gonadotropin-stimulated cycles, since it carries good chances of success while avoiding the risk of massive ovarian hyperstimulation and increased incidence of multiple pregnancies.

[Clomiphene resistant PCO syndrome: IVF treatment as an alternative in failed gonadotropin treatment]. / Clomiphen-resistentes PCO-Syndrom: Die IVF-Behandlung als Alternative bei Versagen der Gonadotropinbehandlung.

34 infertile patients with severe clomiphene-resistant polycystic ovary syndrome were treated with IVF/ET. Stimulation attempts with gonadotropins had resulted in multifollicular ovarian reactions, which did not allow standard ovulation induction using hCG due to the risk of multiple pregnancy. The resulting oocyte retrieval rates (87.4%/treatment cycle), embryo transfer rates (73.3%/oocyte retrieval) and pregnancy rates (24.2%/embryo transfer) approximately corresponded to the rates which are achieved in women with tubal failure using IVF/ET. Since strictly a maximum of 2 embryos was transferred, the occurrence of multiple pregnancies of higher degree could be avoided as opposed to standard gonadotropin therapy. The treatment so far only resulted in singleton pregnancies. The relatively high ovarian hyperstimulation rate (34.4%, primarily WHO stage I-II) could not be unequivocally lowered even by aspiration of all larger follicles.

A three step protocol for the treatment of idiopathic subfertility.

650 couples with idiopathic subfertility (mean duration: 5.7 year, range 2-21 years) were treated during 2870 cycles by three assisted conception methods (each involving mild ovarian stimulation): I timed intercourse (TI), II intrauterine insemination (IUI). III in vitro fertilization/embryo transfer (IVF/ET). Treatment started with TI in most cases and then changed to IUI after three to six cycles. Couples who failed to conceive were treated after another 3-9 cycles by IVF/ET. An overall cumulative pregnancy rate of 80.2% was reached after 18 treatment months. The pregnancy rates per treatment cycle were: TI 5.3%, IUI 6.9%, IVF/ET 15.8% (per oocyte retrieval).

Serum concentration and urinary excretion of "classical" estrogens, catecholestrogens and 2-methoxyestrogens in normal human pregnancy.

Catecholestrogens, 2-methoxyestrogens and "classical" estrogens (estrone, estradiol, estriol) were measured simultaneously in serum and urine samples of 220 pregnant women from the 8th week of pregnancy until to delivery. From these data we established the central 0.80 centile intervals as time specified reference intervals for each substance analyzed. Serum and urinary estradiol rise steadily during the progress of pregnancy, whereas estrone, catecholestrogens and 2-methoxyestrogens reach a plateau during the last trimester. These observations support the hypothesis, that the amount of the latter compounds may be regulated by separate mechanisms. The values of concentration and excretion of 2- and 4-substituted estrogens varied widely throughout pregnancy. Even very high or very low concentrations of these substances had no recognizable relation to the outcome of pregnancy. This supports the assumption that catecholestrogens and their methylethers are metabolites without any regulatory function in pregnancy.

Urinary excretion of catecholestrogens, 2-methoxy-estrogens and "classical estrogens" throughout the normal menstrual cycle.

Catecholestrogens, 2-methoxyestrogens and "classical" estrogens (estrone, estradiol, estriol) were measured simultaneously in urine samples of healthy women during the menstrual cycle. All estrogen values reach a preovulatory maximum at the time of the LH peak and show a marked increase during the luteal phase as compared to the follicular phase. Catecholestrogens and estrone seem to behave similarly supporting the assumption that catecholestrogens are predominantly metabolites of estrone. Daily measurements of urinary estrogens show large interindividual variations of 2- and 4-hydroxyestrogens as well as very differing 2-hydroxy-/2-methoxyestrogen ratios. The results obtained support the assumption, that catecholestrogens and their methylethers are excretory products with no additional regulatory functions.

Familial 46,XY pure gonadal dysgenesis and gonadoblastoma/dysgerminoma: case report.

The case reports of two sisters admitted for evaluation of primary amenorrhea are presented. Gynecological and endocrinological investigations and chromosomal analysis led to the diagnosis of familial 46,XY gonadal dysgenesis. Both sisters underwent bilateral salpingo-oophorectomy and hysterectomy. Histological examination revealed dysgenetic gonads with gonadoblastoma and dysgerminoma. Five years after treatment by surgery and irradiation the patients are well and free of recurrence. These cases again confirm the risk of malignancy and the necessity of prophylactic gonadectomy in all patients with gonadal dysgenesis and Y chromosomal material.

2-Hydroxylation and O-methylation of oestrogens by human placenta in vivo.

Concentrations of unconjugated and conjugated 2-hydroxyoestrogens and their 2-methylethers were determined by radioimmunoassay in serum obtained from the umbilical artery, umbilical vein, retroplacental space, and maternal peripheral vein at the time of delivery. The concentrations of unconjugated 2-hydroxyoestrogens and 2-methoxyoestrogens were found to be significantly higher in the post-placental vessels than in the pre-placental vessels. On the basis of the concentrations measured it was estimated that the placenta secretes about 1.4 nmol/min 2-hydroxyoestrogens and about 1.7 nmol/min of 2-methoxyoestrogens. The present in vivo findings confirm the placental 2-hydroxylase- and catechol-O-methyl-transferase activities previously demonstrated in vitro.