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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This investigation aimed at evaluating a role for frequencies and amplitudes of repeated HCG stimulations for the optimal maintenance of progesterone (P4) secretion from the bovine corpus luteum in vitro. Slices (100-120 mg) of midluteal bovine corpora lutea were perifused with medium M199 (0.05% BSA, pH 7.2, 38.5 degrees C) and the perifusion effluent collected at 15 minute intervals for 20-29 hours. Unstimulated P4 release (n = 5) was distinctly pulsatile (by Pulsar pulse algorithm), with pulses occurring every 90 +/- 6 minutes (mean +/- SEM) and pulse amplitudes of 14.4 +/- 1.1 ng. Conversely, no pulses were detected in two control perifusions. Unstimulated P4 release increased during the first 5 perifusion hours (from 39.3 +/- 4.6 to 50.3 +/- 5.6 ng/15 min, p less than 0.01), but then appeared to decline (to 29.3 +/- 1.3 ng/15 min, p less than 0.05) towards the end of the perifusion periods. Hourly pulses of HCG (6.7 mM) did not change the P4 pulse amplitudes (16.6 +/- 2.0 ng), the pulse periodicities (105 +/- 15 min) and overall release rates (34.7 +/- 5.7 ng/15 min), nor did they prevent the decline in P4 secretion towards the end of perifusions (n = 5). In contrast, 2-hourly HCG stimulations maintained stable P4 release rates throughout the perifusion periods (34.7 +/- 6.8 ng/15 min), with P4 pulses of similar amplitudes (14.7 +/- 1.7 ng), but of lower periodicities (135 +/- 2 min, p less than 0.05) than during unstimulated conditions (n = 5).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Role of frequency and amplitude of repetitive HCG stimulations for sustained progesterone secretion from the bovine corpus luteum in vitro. 157 97

In the present study, we investigated the biological characteristics of different molecular forms of chorionic gonadotrophin (HCG) secreted by the human cytotrophoblast during its morphological and functional differentiation in culture. Highly purified cytotrophoblasts were prepared from term placentae and cultured for 24 to 96 h in the absence or presence of 8-bromo-3',5'-cAMP. Media were collected at 24 h intervals and the secreted isoforms of HCG were then separated by polyacrylamide gel isoelectric focusing (pH range 8.0-3.0) and quantified by radioimmunoassay. The secretion of HCG was significantly increased by 8-bromo-cAMP (from 23.5 +/- 6.3 ng/ml at 24 h to 1619 +/- 835.8 ng/ml at 96 h; controls, 9.3 +/- 0.1 ng/ml at 24 h and 26.6 +/- 3.5 ng/ml at 96 h, mean +/- SD). Analysis of media concentrates from cAMP-stimulated cultures by isoelectric focusing revealed the presence of several distinct peaks of HCG within the pH range of 7.3-4.8; major peaks consistently exhibited isoelectric points (pI) of 7.3-7.0 (peak 1), 5.6-5.4 (peak 2) and 5.1-4.8 (peak 3). The relative HCG content of the most acidic peak (as % of total on gel) progressively increased with time of exposure to the cAMP analogue (from 19.8 +/- 1.6% at 24 h to 34.4 +/- 4.3% at 96 h, mean +/- SEM, P less than 0.01). HCG recovered from peak 1 exhibited the highest receptor-binding capacity and in-vitro biological potency.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Studies on the microheterogeneity of chorionic gonadotrophin secreted by the human cytotrophoblast in culture. 170 40

We did serial determinations of beta-HCG, total-HCG, prolactin, SP-1, and progesterone in maternal serum after operation of an ectopic pregnancy in 38 patients. Prolactin, progesterone and SP-1 rapidly returned to normal values after removal of the ectopic pregnancy. However, the half life of HCG was related to the type of operation: after conservative operation of ectopic pregnancy the half life of HCG was greater than after tubectomy (41.4 +/- 1.9 SEM hours versus 33.4 +/- 2.0 hours), possibly due to lack of complete removal of trophoblast tissue. This fact should be kept in mind when evaluating postoperative HCG levels.
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PMID:[Hormonal pregnancy parameters in the serum following surgery for extrauterine pregnancy]. 244 39

Granulosa cells from porcine ovarian follicles were cultured in vitro in standard medium and in medium supplemented with HCG. After culture the cellular 3 beta HSD enzymatic activity was evaluated and the cells were studied by TEM and SEM. A stereological evaluation of the smooth and rough endoplasmic reticulum was carried out. The results indicate that the cultured cells undergo a luteinization process which is more evident in the presence of HCG. In fact, in comparison with the controls, in these cells the enzymatic activity is higher, the rough endoplasmic reticulum decreases and the smooth endoplasmic reticulum increases, the cytoplasm shows lipid droplets and vesicular mitochondria. The cell surface develops a number of microvillus-like evaginations.
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PMID:On the structural changes of granulosa cells cultured in vitro. Histochemical, ultrastructural and stereological observations. 733 47

Chorionic gonadotrophin (CG) is the first clear embryonic signal during early pregnancy in primates. CG has close structural and functional similarities to pituitary luteinizing hormone (LH) which is regulated by gonadotrophin releasing hormone (GnRH). To study the regulatory mechanism of CG secretion in primate embryos, we examined the production and timing of secretion of GnRH in peri-implantation embryos of the rhesus monkey. In-vivo fertilized/developed morulae and early blastocysts, recovered from non-superovulated, naturally-bred rhesus monkeys by non-surgical uterine flushing, were cultured in vitro to hatched, attached and post-attached blastocyst stages using a well-established culture system. We measured GnRH and CG in media samples from cultured embryos with a sensitive radioimmunoassay and bioassay, respectively. The secretion of GnRH (pg/ml; mean +/- SEM) by embryos (n = 20) commenced from low levels (0.32 +/- 0.05) during the pre-hatching blastocyst stage to 0.70 +/- 0.08 at 6-12 days and 1.30 +/- 0.23 at > or = 13 days of hatched blastocyst attachment and proliferation of trophoblast cells. GnRH concentrations in culture media obtained from embryos (n = 5) that failed to hatch and attach were mostly undetectable (< or = 0.1). Samples that did not contain detectable GnRH failed to show detectable CG. Immunocytochemical studies, using a specific monoclonal anti-GnRH antibody (HU4H) as well as polyclonal antisera (LR-1), revealed that immunopositive GnRH cells were localized in pre-hatching blastocysts (n = 4), in blastocysts (n = 2) after 5-10 days of attachment and in monolayer cultures (n = 4) of well-established embryonic trophoblast cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The secretion of gonadotrophin-releasing hormone by peri-implantation embryos of the rhesus monkey: comparison with the secretion of chorionic gonadotrophin. 796 38

CG produced by fetal tissues extends the functional lifespan of the primate corpus luteum during early pregnancy. Previous studies showed that urinary hCG administered to monkeys to simulate the rising CG levels associated with early pregnancy enhanced both progesterone (P) and relaxin (RLX) production by the corpus luteum. The current study was designed: 1) to compare the ability of recombinant (r) and urinary (u) hCG to stimulate luteal function, and 2) to assess the role of P in the regulation of luteal RLX secretion during simulated early pregnancy by concomitant administration of hCG and the 3 beta-hydroxysteroid dehydrogenase inhibitor trilostane to reduce P production. Rhesus monkeys received injections of either r-hCG or u-hCG (Ares Serono) in increasing doses (15-2880 IU/dose, twice daily) for 9 days beginning on day 9 of the luteal phase (n = 5/group). An additional group (n = 4) received r-hCG as described above, with concomitant oral administration of trilostane (500 mg/dose twice daily; Sanofi Winthrop). Daily serum samples were assayed for hCG by immunoradiometric assay, steroid hormones by RIA, and RLX by enzyme-linked immunosorbent assay. Serum hCG levels typically were not different between the r-HCG and u-hCG groups during or after treatment. Concentrations of hCG peaked 1 day after the final injection in monkeys receiving r-hCG (mean +/- SEM. 2759 +/- 120 mIU/mL) and u-hCG (2120 +/- 60 mIU/mL) and dropped below 5 mIU/mL by 10 days after the final treatment in all groups. Both r-hCG and u-hCG stimulated luteal P and RLX production. Progesterone levels rose rapidly after the initiation of hCG treatment and peaked in animals receiving r-hCG (14.4 +/- 2.8 ng/mL) and u-hCG (11.9 +/- 1.4 ng/mL) 4 days after initial administration. RLX levels peaked in the r-hCG (400 +/- pg/mL) and u-hCG (323 +/- 85 pg/mL) groups within 4 days of the final hCG treatment. Trilostane with r-hCG reduced P concentrations to very low levels (< 0.5 ng/mL; P < 0.01) within 1 day of administration compared to those in animals receiving r-hCG only and maintained these low levels for the entire treatment interval. Nevertheless, trilostane administration did not alter luteal RLX production, with serum levels peaking at 377 +/- 76 pg/mL. These data indicate that r-hCG and u-hCG were equally efficacious in stimulating the steroidogenic and peptidergic activities of the corpus luteum during simulated early pregnancy. In addition, P deprivation during r-hCG administration did not alter circulating RLX levels, suggesting that P is not a major regulator of RLX production by the primate corpus luteum during early pregnancy.
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PMID:Stimulation of primate luteal function by recombinant human chorionic gonadotropin and modulation of steroid, but not relaxin, production by an inhibitor of 3 beta-hydroxysteroid dehydrogenase during simulated early pregnancy. 896 69

The relationship was investigated between different ultrasonographically defined subtypes of the human corpus luteum and progesterone production. Twenty-one women in the mid-luteal phase who underwent laparotomy for benign uterine conditions volunteered for this study. The corpus luteum was identified by preoperative ultrasound and classified into four types according to earlier established criteria, where types a and c were centrally hypoechoic, types b and d were centrally echogenic, types a and b had thin surrounding 'walls' (<3 mm) and types c and d had thick walls (<3 mm). After luteectomy, the theca externa capsule was removed and tissue from directly beneath the surface ('peripheral region') and the layer immediately beneath ('inner region') minced into 4-6 mg pieces. Following preincubation, pieces were incubated for 3 h at 37 degrees C in HEPES-minimal essential medium buffer with or without human chorionic gonadotrophin (HCG; 10 IU/ml), and subsequently progesterone accumulation in the medium was determined by radioimmunoassay. The highest progesterone production was consistently seen in the peripheral region. Type a had a significantly (P > 0.01) lower progesterone production (3.2 +/- 1.5 nmol/g tissue wet weight, mean +/- SEM, n = 4) than that of types b, c and d (17.7 +/- 3.5 nmol/g tissue wet weight, n = 9). All types responded to HCG with an almost two-fold increase in progesterone production. However, the maximal progesterone produced following stimulation by HCG in the type a corpus luteum was <50% of the basal (unstimulated) progesterone synthesis of any other type of corpus luteum. Using in-situ hybridization, with a primate RNA probe complementary to the region coding the extracellular part of the luteinizing hormone (LH) receptor, a highly localized expression of LH receptor mRNA to the peripheral region was found. Negligible or low levels of expression were found in the theca externa capsule and the inner region. No obvious correlations between the different subtypes of corpora lutea and LH receptor mRNA expression were seen. Thus, the ultrasonographic detection of a thin-walled and centrally hypoechoic corpus luteum correlates well with reduced progesterone secretion. The underlying cellular mechanism does not appear to involve a diminished sensitivity to the gonadotrophic stimulation by LH or HCG.
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PMID:Compartmentalization of human chorionic gonadotrophin sensitivity and luteinizing hormone receptor mRNA in different subtypes of the human corpus luteum. 919 62

Gonadotropin (Gn) replacement therapy using HCG plus HU-FSH was administered to 24 patients affected by beta-thalassaemia major with hypogonadotropic hypogonadism aged 18-40 years (25.2 +/- 5.4 yr, m +/- SEM). The age range at the start of treatment was 14.5-24.5 years (16.7 +/- 2.6 yr); the mean duration of Gn treatment was 8.6 +/- 3.9 years (range 1-15.2 yr). Gn therapy was begun with HCG alone, the dosage being initially 500 IU twice a week and then increased to a maximum of 3000 IU twice a week, according to the individual serum testosterone levels obtained. HU-FSH (75 IU twice a week) was added to initiate spermatogenesis in all cases when the HCG-induced testosterone serum levels normalized. The duration of HU-FSH treatment ranged from 1-2 years and then therapy was continued with HCG alone. In nine patients Gn therapy was discontinued after 6-14 years and was replaced by testosterone depot therapy, 75-100 mg i.m. twice a month, for a period ranging from 1-1.5 years. Using Gn therapy, the testosterone levels normalized. The compliant patients obtained good virilization and normal sexual function; testicular volume increased within the normal adult range and spermatogenesis was achieved. When Gn therapy was replaced by testosterone-depot therapy, a marked decrease in testicular volume and sperm count was observed, but the patients complied better and showed a slight increase in coarse hair. In conclusion gonadotropins are an effective replacement therapy for male hypogonadism in thalassaemic patients. If we consider the advantages and disadvantages of this therapy, the former seem to outweigh the latter. Finally, it should be emphasized that physicians caring for these patients must foster compliance during frequent check-ups and examinations.
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PMID:Hormonal replacement therapy with HCG and HU-FSH in thalassaemic patients affected by hypogonadotropic hypogonadism. 1009 Nov 62

Prediction of poor-response is of equal importance to prediction of over-response in intrauterine insemination programmes. The gonadotrophin-releasing hormone agonist (GnRHa) stimulation test (GAST) was assessed as a predictor of over-response to ovarian stimulation in 81 patients. Blood samples were taken on cycle day 2 (before and 24 h after starting the GnRHa). Day 2 and 3 samples were assayed for oestradiol, follicle stimulating hormone (FSH) and luteinizing hormone (LH). Linear and logistic regression analyses were used to assess age, day 2 FSH, day 2 FSH/LH, oestradiol ratio (oestradiol on day 3/oestradiol on day 2) and FSH ratio (FSH on day 3/FSH on day 2) as predictors of the number of follicles (total and > or = 14 mm), oestradiol on HCG day, and clinical pregnancy rate as appropriate. Several parameters were also compared between the patients who produced < or = 3 (> or = 14 mm) follicles (group A) and those who produced >3 (> or = 14 mm) follicles (group B). The mean +/- SEM age of the patients in the study was 32 +/- 0.4 years. The mean total dose of recombinant FSH was 800 +/- 20 IU and the mean duration of stimulation was 7.6 +/- 0.2 days. Nine (11%) and 12 (15%) patients were cancelled for poor and over-response respectively. The oestradiol ratio was significantly positively correlated with oestradiol on HCG day (P < 0.001), and with the number of mature follicles (> or = 14 mm) (P = 0.01). Age, day 2 FSH and FSH ratio were not significantly correlated with oestradiol on HCG day, total follicles and follicles > or = 14 mm. None of the above-mentioned variables was correlated with clinical pregnancy rate. Group A had significantly lower oestradiol ratio (P = 0.007), longer duration of stimulation (P = 0.002), higher total FSH dose (P = 0.001), and lower oestradiol on HCG day (P = 0.001). GAST is therefore useful in predicting the high responders to gonadotrophin stimulation.
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PMID:Prediction of over-response to ovarian stimulation in an intrauterine insemination programme. 1054 16

Intact pregnancy can be interpreted as a state of maternal immunotolerance toward an haploidentical fetus. Soluble HLA (sHLA) molecules increase during episodes of allograft rejection and are discussed as candidates to modulate immune responses. We questioned whether after in vitro fertilization (IVF) the subsequent intact pregnancy, early abortion, or tubal pregnancy influence the courses sHLA serum levels. Therefore, serum samples of 65 IVF patients were assayed by ELISA for sHLA-I, sHLA-G, and sHLA-DR concentrations preovulatorily and after a positive HCG test weekly until the 9th gestational week (GW). In 20 patients experiencing an early abortion the preovulatory sHLA-G mean level of 25.9 +/- 3.9 SEM ng/ml and the share of 4.2 +/- 0.8 SEM % on total sHLA-I were significantly (p < 0.05) reduced compared to women with intact pregnancy. The same differences (p < 0.0001) were seen during the monitoring of sHLA-G and sHLA-I levels in intact pregnancy versus early abortion until 9th GW. Twin pregnancy revealed a drastically increase of sHLA-G levels from the 8th GW compared to singleton pregnancies. Further, individual sHLA-DR levels increased during intact pregnancy but decreased in the group of early abortion. With regard to sensitivity and specificity for pregnancy outcome sHLA quantitation reached similar weight as routine HCG determinations at GW 5. Especially women with preovulatory low sHLA-G levels appear to be on risk for early abortion after IVF.
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PMID:Soluble HLA levels in early pregnancy after in vitro fertilization. 1082 84


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