Frozen embryo transfer and preeclampsia: where is the link?

PURPOSE OF REVIEW: Preeclampsia is the leading cause of maternal death and has a higher incidence in patients undergoing assisted reproduction treatments. New studies about the mechanisms by which it is more frequent in this population have emerged. The purpose of this review is to gather current information about the available results on this correlation and its possible physiopathology. RECENT FINDINGS: Recent publications on the physiopathology of preeclampsia indicate that the corpus luteum is the main source of hormonal production until placental formation and that apart from the secretion of estrogen and progesterone, corpus luteum also produces important substances involved in maternal circulatory adaptation, such as relaxin.With the recent increasing number of frozen embryos transfer in natural cycles or under hormonal replacement, this adaptive circulatory process may be unbalanced and predispose this population to preeclampsia. SUMMARY: This article provides a review of frozen embryo transfer and available protocols, the highest incidence of gestational hypertensive disorders presented by the infertile population and an overview of the possible impact of the absence of corpus luteum on the genesis of this disease.

Circulatory microRNA 23a and microRNA 23b and polycystic ovary syndrome (PCOS): the effects of body mass index and sex hormones in an Eastern Han Chinese population.

BACKGROUND: MicroRNAs (miRNAs) regulate the expression of genes involved in various cellular functions related to metabolism, inflammation, and reproduction. This study evaluated the effects of sex hormones and obesity on the expression of circulating miR-23a and miR-23b in women with polycystic ovary syndrome (PCOS) and healthy women. METHODS: Serum sex hormones concentrations and body mass index (BMI) were measured in 18 women with PCOS and in 30 healthy women from the East China area and these measurements were correlated with serum miR-23a/b levels. The effect of miR-23a and miR-23b risk factors on occurrence of PCOS and predisposing factors of PCOS on these miRNA expressions were evaluated. RESULTS: The expressions of miR-23a/b were significantly lower in the women with PCOS than the normal women, and the expression levels of miR-23a/b were positively correlated with each other in the normal women (p = 0.001) but not in the women with PCOS (p > 0.05). In the women with PCOS, miR-23a was positively correlated with BMI (p = 0.03). However, no correlations were found between the levels of miR-23a/b and the sex hormones in the normal and PCOS women. On the other hand, without considering the presence or absence of PCOS, increase in BMI had a positive effect on the levels of circulating miR-23b; while testosterone had negative effects on the levels of circulating miR-23a. Furthermore, the likelihood of women with PCOS decreased by 0.01-fold for every 1 fold increase of miR-23a expression. CONCLUSIONS: Both reduced levels and discordance between the expressions of miR-23a/b were observed in the women with PCOS and miR-23a/b were affected from testosterone and BMI, reversely. Therefore, miR-23a alteration in contrast with miR-23b is a better indicator for evaluation of PCOS than the miR-23b.

What is the optimal means of preparing the endometrium in frozen-thawed embryo transfer cycles? A systematic review and meta-analysis.

BACKGROUND Frozen-thawed embryo transfer (FET) enables surplus embryos derived from IVF or IVF-ICSI treatment to be stored and transferred at a later date. In recent years the number of FET cycles performed has increased due to transferring fewer embryos per transfer and improved laboratory techniques. Currently, there is little consensus on the most effective method of endometrium preparation prior to FET. METHODS Using both MEDLINE and EMBASE database a systematic review and meta-analysis of literature was performed. Case-series, case-control studies and articles in languages other than English, Dutch or Spanish were excluded. Those studies comparing clinical and ongoing pregnancy rates as well as live birth rates in (i) true natural cycle FET (NC-FET) versus modified NC-FET, (ii) NC-FET versus artificial cycle FET (AC-FET), (iii) AC-FET versus artificial with GnRH agonist cycle FET and (iv) NC-FET versus artificial with GnRH agonist cycle FET were included. Forest plots were constructed and relative risks or odds ratios were calculated. RESULTS A total of 43 publications were selected for critical appraisal and 20 articles were included in the final review. For all comparisons, no differences in the clinical pregnancy rate, ongoing pregnancy rate or live birth rate could be found. Based on information provided in the articles no conclusions could be drawn with regard to cancellation rates. CONCLUSIONS Based on the current literature it is not possible to identify one method of endometrium preparation in FET as being more effective than another. Therefore, all of the current methods of endometrial preparation appear to be equally successful in terms of ongoing pregnancy rate. However, in some comparisons predominantly retrospective studies were included leaving these comparisons subject to selection and publication bias. Also patients' preferences as well as cost-efficiency were not addressed in any of the included studies. Therefore, prospective randomized studies addressing these issues are needed.

Potencial envolvimento da adiponectina e seus receptores na modulação da esteroidogênese em corpo lúteo de cadelas ao longo do diestro / Potential involvement of adinopectin and its receptors in the modulation of steroidogenesis in corpus luteum of bitches during diestrus

No ciclo estral de cadelas a fase luteínica, denominada diestro, compreende um período que varia de 60 a 100 dias em animais não-prenhes, caracterizado pela elevação plasmática de progesterona nos primeiros 20 dias pós ovulação (p.o). A adiponectina é a mais abundante proteína secretada pelo tecido adiposo, porém sua concentração plasmática diminui significativamente em alterações metabólicas como resistência insulínica e Diabetes mellitus tipo2, alterações descritas como relacionadas em algumas cadelas com o período de diestro. O objetivo do estudo foi determinar a expressão e imunolocalização do sistema adiponectina (adiponectina e seus receptores, adipoR1 e adipoR2) no corpo lúteo de cadelas ao longo do diestro, correlacionando-o ao perfil hormonal de 17β-estradiol e progesterona, assim como à expressão de um dos genes alvo do sistema, o PPAR-γ. Para realização do estudo foram coletados corpos lúteos de 28 cadelas durante ovariosalpingohisterectomia de eleição nos dias 10, 20, 30, 40, 50, 60 e 70 pós ovulação (o dia zero da ovulação foi considerado aquele no qual a concentração plasmática de progesterona atingiu 5ng/mL). Os corpos lúteos foram avaliados por imunohistoquímica para adiponectina e seus receptores e a expressão do RNAm do PPAR-γ por PCR em tempo real. A análise estatística da avaliação gênica foi realizada com o teste ANOVA, seguido por comparação múltipla Newman-Keuls. O sinal da adiponectina apresentou-se mais intenso até os primeiros 20 dias p.o, momento de regência da progesterona; houve queda gradativa após este período, coincidindo com a ascensão do 17β-estradiol, cujo pico foi notado próximo do dia 40 p.o. A queda marcante da adiponectina ocorreu após 50 dias p.o. O sinal do adipoR1 mostrou-se bem evidente até os 40 dias p.o e o do adipoR2 até os 50 dias p. o, decaindo posteriormente. Foi observada maior expressão do gene PPAR-γ aos 10, 30 e 70 dias p.o. Estes resultados mostram que a expressão protéica da adiponectina e de seus receptores se altera ao longo do diestro e que estas alterações podem estar relacionados às alterações hormonais e expressão do PPAR- γ, participando do mecanismo fisiológico de desenvolvimento, manutenção, atividade e regressão luteínica em cadelas.

In the estrous cycle of bitches, the luteal phase or diestrus includes a period ranging from 60 to 100 days in non-pregnant animals, characterized by elevated serum progesterone during the first 20 days post-ovulation (p.o). Adiponectin is the most abundant protein secreted by adipose tissue, but plasma concentration decreases significantly in metabolic disorders like insulin resistance and diabetes mellitus type 2, described as related changes in some bitches in diestrus. The aim of this study was to determine the expression and immunolocalization of the adiponectin system (adiponectin, and adipoR1 adipoR2) in the corpus luteum during diestrus, and correlate it to hormonal profile of 17β-estradiol and progesterone, as well as the expression of a gene target of the system, the PPAR-γ. For the study, corpora lutea were collected from 28 dogs during ovariosalpingohysterectomy on days 10, 20, 30, 40, 50, 60 and 70 post ovulation (day zero of ovulation was considered the day when the plasma progesterone concentration reached 5ng/mL). The corpora lutea were evaluated by immunohistochemistry for adiponectin, adipoR1 and adipoR2 and mRNA expression of PPAR-γ by real-time PCR. Statistical analysis of gene expression was performed with ANOVA followed by Newman-Keuls multiple comparisons. Adiponectin positive signal was stronger during the first 20 days p.o, time of the regency of progesterone; there was a gradual adiponectin and progesterone decline after this period, coinciding with the rise of 17β-estradiol, whose peak was near the 40 days p.o. The markedly adiponectin decrease occurred after 50 days p.o. The signal of adipoR1 was markedly evident at 40 days p.o and that of adipoR2 up to 50 days p.o, declining afterwards. We observed higher expression of PPAR-γ gene at 10, 30 and 70 days p.o. These results show that adiponectin and its receptors protein expression is altered during the diestrus and that these changes may be related to hormonal changes and expression of PPAR-γ, participating in the physiological mechanism of development, maintenance, activity and luteal regression in bitches.

Survival role of locally produced acetylcholine in the bovine corpus luteum.

The present study was conducted to explore the source of acetylcholine (ACH) in the corpus luteum (CL) and to test our hypothesis of an antiapoptotic role of ACH in the bovine CL and, further, to investigate whether nerve growth factor (NGF), insulin-like growth factor 1 (IGF1), and transforming growth factor beta1 (TGFB1) influence the expression of choline acetyltransferase (CHAT), the biosynthetic enzyme of ACH, in cultured bovine luteal cells. Protein expression and immunolocalization of CHAT were carried out at different stages throughout the luteal phase and in cultured luteal and endothelial cells. ACH was measured in luteal tissue at the different luteal stages and in luteal cells cultured for 8 and 24 h. Cell viability and TUNEL assays were performed on cultured midluteal cells treated with or without tumor necrosis factor alpha (TNF)/interferon gamma (IFNG) in the presence of ACH and its muscarinic (atropine) and nicotinic (mecamylamine) receptor antagonists. The CL was devoid of cholinergic nerve fibers. CHAT immunostaining was evident in luteal, endothelial, and stromal cells in luteal tissue sections and in cultured luteal and endothelial cells. CHAT protein was expressed throughout the cycle without any significant changes. ACH concentration in luteal tissue was not changed during the luteal stages but increased over time and with increased cell numbers in luteal cell cultures. ACH increased cell viability and prevented cell death induced by TNF/IFNG. Atropine significantly attenuated ACH action, whereas mecamylamine had no effect. TNF/IFNG treatment downregulated CHAT expression, whereas NGF, IGF1, and TGFB1 upregulated CHAT expression, in cultured luteal cells. The overall findings strongly suggest a nonneural source and antiapoptotic role of ACH in the bovine CL. Locally produced ACH appears to be regulated by NGF, IGF1, and TGFB1.

The absence of corpus luteum formation alters the endocrine profile and affects follicular development during the first follicular wave in cattle.

We previously established a bovine experimental model showing that the corpus luteum (CL) does not appear following aspiration of the preovulatory follicle before the onset of LH surge. Using this model, the present study aimed to determine the profile of follicular development and the endocrinological environment in the absence of CL with variable nadir circulating progesterone (P(4)) concentrations during the oestrous cycle in cattle. Luteolysis was induced in heifers and cows and they were assigned either to have the dominant follicle aspirated (CL-absent) or ovulation induced (CL-present). Ultrasound scanning to observe the diameter of each follicle and blood collection was performed from the day of follicular aspiration or ovulation and continued for 6 days. The CL-absent cattle maintained nadir circulating P(4) throughout the experimental period and showed a similar diameter between the largest and second largest follicle, resulting in co-dominant follicles. Oestradiol (E(2)) concentrations were greater in the CL-absent cows than in the CL-present cows at day -1, day 1 and day 2 from follicular deviation. The CL-absent cows had a higher basal concentration, area under the curve (AUC), pulse amplitude and pulse frequency of LH than the CL-present cows. After follicular deviation, the CL-absent cows showed a greater basal concentration, AUC and pulse amplitude of growth hormone (GH) than the CL-present cows. These results suggest that the absence of CL accompanying nadir circulating P(4) induces an enhancement of LH pulses, which involves the growth of the co-dominant follicles. Our results also suggest that circulating levels of P(4) and E(2) affect pulsatile GH secretion in cattle.

[Physiology of ovulation and mode of action of contraceptive pills]. / Physiologie de l'ovulation et mode d'action de la contraception.

Follicular ovulation occurs at most 400 times in a woman's lifetime. This process involves enzymatic destruction of the cells surrounding the oocytes, called cumulus oophorus. The three different partners in order to obtain normal ovulation are the oocytes, the mature follicle containing adequate LH receptors and the hormones, especially progesterone and the preovulatory LH surge. Contraceptive pills available so far contain ethynyl estradiol, in order to regulate bleedings. The different progestins in the contraceptive pill exert an antigonadotropic effect and therefore inhibit follicular recruitment. As third generation progestins exert a stronger antigonadotropic effect than previous progestins, the dose of ethynyl estradiol has been lowered in the past 50 years.

Changes in expression of 11beta-hydroxysteroid dehydrogenase type-1, type-2 and glucocorticoid receptor mRNAs in porcine corpus luteum during the estrous cycle.

The objective of the present study was to determine whether glucocorticoid (GC) and its receptor (GC-R) are expressed in the porcine corpus luteum (CL), and whether GC influences porcine luteal hormone production. The gene expressions of 11beta-hydroxysteroid dehydrogenase type 1 (11-HSD1), type 2 (11-HSD2), GC-R, and the concentrations of GC were determined in the CL of Chinese Meishan pigs during the estrous cycle. Moreover, the effects of GC on progesterone (P(4)), estradiol-17beta (E(2)), and prostaglandin (PG) F2alpha secretion by cultured luteal cells were investigated. Messenger RNAs of the 11-HSD1, 11-HSD2, and GC-R were clearly expressed in the CL throughout the estrous cycle. The 11-HSD1 mRNA level in the CL was higher at the regressed stage than at the other stages (P < 0.05), whereas 11-HSD2 mRNA was lower at the regressed stage than at the other stages (P < 0.05). GC-R mRNA level was higher at the regressed stages than at the other stages (P < 0.01). Concentrations of GC were lower in the regressed CL than in the other stages (P < 0.01). When the cultured luteal cells obtained from mid-stage CL (Days 8-11) were exposed to GC (50-5,000 ng/ml), P(4) and PGF2alpha secretion by the cells were reduced (P < 0.05), whereas GC had no effect on E(2) secretion by the cells. The overall results suggest that GC is regulated locally by 11-HSD1 and 11-HSD2 in the porcine CL. GC inhibits P(4) and PGF2alpha production from luteal cells via their specific receptors, implying GC plays some roles in regulating porcine CL function throughout the estrous cycle.

Judge, jury and executioner: the auto-regulation of luteal function.

Experiments were conducted to further our understanding of the cellular and molecular mechanisms that regulate luteal function in ewes. Inhibition of protein kinase A (PKA) reduced (P < 0.05) secretion of progesterone from both small and large steroidogenic luteal cells. In addition, the relative phosphorylation state of steriodogenic acute regulatory protein (StAR) was more than twice as high (P < 0.05) in large vs small luteal cells. Large steroidogenic luteal cells appear to contain constitutively active PKA and increased concentrations of phosphorylated StAR which play a role in the increased basal rate of secretion of progesterone. To determine if intraluteal secretion of prostaglandin (PG) F2alpha was required for luteolysis, ewes on day 10 of the estrous cycle received intraluteal implants of a biodegradable polymer containing 0, 1 or 10 mg of indomethacin, to prevent intraluteal synthesis of PGF2alpha. On day 18, luteal weights in ewes receiving 1 mg of indomethacin were greater (P < 0.05) than controls and those receiving 10 mg were greater (P < 0.05) than either of the other two groups. Concentrations of progesterone in serum were also increased (P < 0.05) from days 13 to 16 of the estrous cycle in ewes receiving 10 mg of indomethacin. Although not required for decreased production of progesterone at the end of the cycle, intraluteal secretion of PGF2alpha appears to be required for normal luteolysis. To ascertain if oxytocin mediates the indirect effects of PGF2alpha on small luteal cells, the effects of 0, 0.1, 1 or 10 mM oxytocin on intracellular concentrations of calcium were quantified. There was a dose-dependent increase (P < 0.05) in the number of small luteal cells responding to oxytocin. Thus, oxytocin induces increased calcium levels and perhaps apoptotic cell death in small luteal cells. Concentrations of progesterone, similar to those present in corpora lutea (approximately 30 microg/g), prevented the increased intracellular concentrations of calcium (P < 0.05) stimulated by oxytocin in small cells. In large luteal cells the response to progesterone was variable. There was no consistent effect of high quantities of estradiol, testosterone or cortisol in either cell type. It was concluded that normal luteal concentrations of progesterone prevent the oxytocin and perhaps the PGF2alpha-induced increase in the number of small and large luteal cells which respond to these hormones with increased intracellular concentrations of calcium. In summary, large ovine luteal cells produce high basal levels of progesterone, at least in part, due to a constituitively active form of PKA and an enhanced phosphorylation state of StAR. During luteolysis PGF2alpha of uterine origin reduces the secretion of progesterone from the corpus luteum, but intraluteal production of PGF2alpha is required for normal luteolysis. Binding of PGF2alpha to receptors on large luteal cells stimulates the secretion of oxytocin which appears to activate PKC and may also inhibit steroidogenesis in small luteal cells. PGF2alpha also activates COX-2 in large luteal cells which leads to secretion of PGF2alpha. Once intraluteal concentrations of progesterone have decreased, oxytocin binding to its receptors on small luteal cells also results in increased levels of intracellular calcium and presumably apoptosis. Increased secretion of PGF2alpha from large luteal cells activates calcium channels which likely results in apoptotic death of this cell type.

Aggression, impulsivity, plasma sex hormones, and biogenic amine turnover in a forensic population of rapists.

The aim of the present study was to assess androgen plasma levels and biogenic amine metabolites in a sex-offender group as well as to investigate the relationship between the biological findings and the impulsive, aggressive, and suicidal profile of the offenders. Fifty-seven males convicted for rape and 25 normal males comprised the study sample. We found that although both testosterone levels and aggression-impulsivity scores were higher in the group of rapists, testosterone levels were not associated with the aggression and impulsivity scores. Nevertheless, aggression-impulsivity scores were clearly associated with luteinizing hormone levels. This association may indicate a hyperactive hypothalamic-pituitary-gonadal axis, possibly the result of a reduced serotonergic activity.

Neuroendocrinology briefings 12: The maternal brain.

The mother's brain is prepared by the hormones of pregnancy to show the strong maternal feelings that ensure the newborn is cared for. These hormones induce a cascade of changes in the brain, reducing stress reactions, evoking maternal behaviour and preparing the neuroendocrine circuits that drive the birth process and ensure that the suckling infant gets milk. The nerve cells that make oxytocin are involved in all of these aspects of motherhood, and details are emerging of how their performance is adapted by pregnancy.

The role of luteal steroid hormones in the regulation of the estrous cycle of high fecundity Olkuska sheep.

The study was undertaken to investigate the steroid hormone production by sheep luteal cells. Corpora lutea were collected from 30 Olkuska sheep on Days 3, 6, 9, 12 and 15 of the estrous cycle during the reproductive season. In Experiment 1, steroid hormone concentration was estimated in extracts of CL. In Experiment 2, luteal cells were cultured in vitro for 24 h. Luteal cells isolated on Days 9 and 12 secreted high amounts of progesterone and androgens but smaller amounts of estradiol. Concentration of these steroids in CL extracts collected on the same days showed the same trend. In CL harvested on Day 15, a decrease in androgens and progesterone as well as a significant increase in estradiol were observed in culture media and in extracts. Judging from the high amounts of estradiol and low amounts of androgen observed at the end of the luteal phase, we speculate that the steroid hormones secreted by the regressing CL may play an active role in the regulation of the estrous cycle in the Olkuska sheep with autocrine influence on the luteal activity or a possible paracrine action on follicular growth. In the third Experiment, the possibility of heterogeneity in the multiple corpora lutea population of prolific Olkuska sheep was investigated. Differences were found in the level of progesterone and estradiol secretion by individual corpora lutea recovered from the same animal, which also varied in terms of weight. This is the first study which shows the existence of intra-ovarian and individual heterogeneity between corpora lutea recovered from ewes during the normal estrous cycle.

[Aids in the management of pathological pregnancies. Advances in current knowledge of corpus luteum function]. / Hjälp vid handläggning av patologiska graviditeter. Ny kunskap om gulkroppens funktion.

Technological advances during the past decade have yielded new knowledge of luteal function and its regulation. A number of new substances with luteotrophic and lutcolytic properties have been identified in the corpus luteum, and the picture which emerges of the mechanisms responsible for physiological luteolysis is becoming increasingly complex. As luteal function/regulation during the menstrual cycle in the absence of pregnancy differs both from that in normal pregnancy, and from that in pathological pregnancy, these advances in our knowledge should prove clinically useful, particularly with regard to the early diagnosis and management of pathological pregnancy.

Control of human luteal steroidogenesis: role of growth hormone-releasing hormone, vasoactive intestinal peptide, and pituitary adenylate cyclase-activating peptide.

OBJECTIVE: To examine the possible effect of growth hormone-releasing hormone (GHRH), vasoactive intestinal peptide, and pituitary adenylate cyclase-activating peptide on basal and hCG-stimulated P production by human luteal cells. DESIGN: Cultures of human luteal cells from the early and midluteal phase. SETTING: All corpora lutea were obtained from the Obstetrics and Gynecology Department of the Università Cattolica, a public care center. PATIENT(S): Ten nonpregnant women between 35 and 47 years of age underwent surgery for various nonendocrine disorders, such as leiomyomatosis. INTERVENTION(S): Corpora lutea were obtained at the time of hysterectomy. MAIN OUTCOME MEASURE(S): Luteal cells were incubated with GHRH, vasoactive intestinal peptide, and pituitary adenylate cyclase-activating peptide with or without hCG at different concentrations. RESULT(S): Pituitary adenylate cyclase-activating peptide stimulated P production in a dose- and time-dependent manner, whereas GHRH and vasoactive intestinal peptide did not affect luteal steroidogenesis. None of the three peptides were found to synergize with hCG. CONCLUSION(S): Pituitary adenylate cyclase-activating peptide can influence human luteal steroidogenesis.

Primiparous rhesus monkey mothers are more sensitive to the nursing-induced inhibition of LH and ovarian steroid secretion.

The duration of lactational infertility is prolonged significantly in adolescent, primiparous rhesus monkey (Macaca mulatta) mothers compared with adult, multiparous mothers. The present study examined the hypothesis that this parity/age difference in lactational infertility is due to a difference in the physiological responsiveness to nursing behaviour between adolescent and fully adult mothers and is not a consequence of differences in nursing behaviour, per se. At 22 weeks postpartum, mother-infant pairs were randomly assigned to one of four conditions: primiparous, nursing restricted (PR; n = 9); primiparous, nursing unrestricted (PU; n = 11); multiparous, nursing restricted (MR; n = 12); and multiparous, nursing unrestricted (MU; n = 8). Nursing was restricted for a 2-week period by mothers wearing a primate vest which prevented suckling behaviour but allowed infants to interact with their mothers. Nursing restriction resulted in a significant increase in serum oestradiol concentrations in both PR and MR mothers. Although nursing bout frequencies and durations were similar between PU and MU mothers, serum oestradiol also rose in MU mothers but remained suppressed in PU mothers. Once the nursing manipulation period ended and all mothers were allowed to nurse ad libitum, serum oestradiol concentrations continued to rise in all but the PU mothers. This brief interruption of nursing at 22 weeks postpartum advanced the subsequent timing of the first postpartum ovulation in MR and PR mothers relative to that of PU mothers. Again, despite similarities in nursing behaviour, the occurrence of first ovulation was also advanced in MU mothers compared with PU mothers. Just prior to the first postpartum ovulation, females were randomly assigned to one of four treatment groups to determine the effects of nursing behaviour on the hormonal parameters of the luteal phase: primiparous, nursing restricted (PRL; n = 9); primiparous, nursing unrestricted (PUL; n = 11); multiparous, nursing restricted (MRL; n = 10); and multiparous, nursing unrestricted (MUL; n = 10). Nursing restriction significantly elevated serum progesterone concentrations in PRL females compared with other mothers. Serum concentrations of oestradiol were higher in PRL, MRL and MUL mothers relative to PUL females. Again, this difference in oestradiol between PUL and MUL mothers occurred despite similarities in nursing behaviour. These data suggest that parity/age differences in the period of lactational infertility are not due to differences in nursing behaviour but rather to an increased sensitivity to the inhibitory aspects of the suckling stimulus in adolescent primiparous mothers.(ABSTRACT TRUNCATED AT 400 WORDS)

Superoxide dismutase activity, lipid peroxide production and corpus luteum steroidogenesis during natural luteolysis and regression induced by oestradiol deprivation of the ovary in pseudopregnant rabbits.

The relationship of oxygen free radicals to corpus luteum function in rabbits was explored during various stages of pseudopregnancy, including natural and induced luteal regression. Induced luteolysis was achieved during mid-pseudopregnancy by removal of an oestradiol capsule placed at the onset of pseudopregnancy, which suppressed ovarian oestradiol production. Activity of manganese superoxide dismutase (Mn SOD) was significantly and positively correlated with ovarian progesterone production (P < 0.01) throughout pseudopregnancy and during natural regression. Oestradiol deprivation for 12, 24 or 72 h resulted in declines in Mn SOD activity and progesterone secretion, although Mn SOD rose and corpus luteum steroidogenesis was restored to normal when the capsule was replaced for 48 h before assessment, having been removed for 24 h. Lipid peroxide and progesterone concentrations were not correlated, although a significant rise in lipid peroxides in the luteal tissue was detected after deprivation of oestradiol for 72 h. Changes in progesterone production and Mn SOD activity were not associated with alterations in concentration of prostaglandin F metabolite. These data suggest that Mn SOD may be involved in regulating function of the corpus luteum during pseudopregnancy in rabbits and that oxygen free radicals may play a role in regression of corpus luteum in this species.

[New aspects concerning the corpus luteum]. / Nuovi aspetti riguardanti il corpo luteo.

We have summed up current knowledge about the formation and lysis of corpus luteum with the co-ordinate intervention of luteotrophic and luteolytic factors. Then we re-examined the function of the corpus luteum in the physiologic menstrual cycle and in the first period of pregnancy, with special attention to luteal insufficiency as a cause of endocrine miscarriage.

[Corpus luteum defect. Analysis of 30 cases in clinical pregnancy]. / Cuerpo lúteo deficiente. Análisis de 30 casos con embarazo clínico.

Deficient corpus luteum (DCL) is an ovulatory dysfunction little defined but real. It is said that is frequency is 3 and 10% of sterile couples and 30 to 40% of habitual abortion. Is part of the group of ovulatory aberrations together with in situ luteinization and syndrome of not broken luteinized folicle. The diagnosis is based in endometrial morphology and progesterone determination. The objective of this work is to analyze 30 cases of DCL that achieved pregnancy. The diagnosis was done based on low determination of progesterone in serum, biopsy of irregular or indysphase endometrium and all the factors, remaining normal of esterility. Average age of patients was 36 years and for sterility 3.1. Treatment consisted in clomiphen cytrate (CC) administration 100 mg daily of hCG in 21 cases, CC only in eight cases and associated to bromocriptine in one case (concomitant hyper-prolactinemia); 26 pregnancies went to term, seven of them with support of exogenous progesterone the first weeks. There were three abortions and an ectopic one. It is concluded that with a complete study of sterility that only shows low seric progesterone and/or endometrium in dysphase or irregular, the diagnosis of DCL is probable and should be treated first with CC plus hCG. The evolution of pregnancies is normal and according to these results is little acceptable the use of progesterone as a support in pregnancy.