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1.
J Assist Reprod Genet ; 39(12): 2747-2754, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36374395

RESUMEN

PURPOSE: To assess if there is an optimal oocyte retrieval (OR) technique to retrieve a maximum number of oocytes and mature oocytes (MII). METHODS: Retrospective cohort study in which nine physicians completed a survey on OR techniques. Number of oocytes/follicle cohort, MIIs/follicle cohort, and MIIs/oocytes retrieved (%MII) were assessed for each technique for patients undergoing OR from 3/2013 to 7/2019. Data were stratified by number of follicles on ultrasound on day of trigger (< 6, 6-10, > 10). RESULTS: Patient demographics were equivalent between techniques. For < 6 follicles, three techniques resulted in significantly fewer oocyte/follicle (0.97 ± 0.48, 0.95 ± 0.66, and 0.90 ± 0.41) compared to the top-performing technique (TPT) (1.11 ± 0.55). For 6-10 follicles, two techniques resulted in significantly fewer oocyte/follicle (0.95 ± 0.39 and 0.93 ± 0.35) compared to the TPT (1.06 ± 0.42). A different technique had higher %MII (0.77 ± 0.19) compared to two techniques (0.74 ± 0.21 and 0.72 ± 0.22). For > 10 follicles, two techniques resulted in significantly fewer oocyte/follicle (1.01 ± 0.42 and 1.07 ± 0.40) compared to the TPT (1.15 ± 0.41). These two techniques also resulted in fewer MII/follicle (0.75 ± 0.33 and 0.81 ± 0.34 vs. 0.87 ± 0.34). There was no consistent TPT across follicle number groups or for all outcome variables. CONCLUSIONS: There does not appear to be a clear TPT, even for patients with few follicles. Providers who perform OR in a similar fashion to physicians at our institution should feel confident that those techniques obtain equivalent oocyte yields.


Asunto(s)
Recuperación del Oocito , Oocitos , Femenino , Animales , Recuperación del Oocito/métodos , Estudios Retrospectivos , Folículo Ovárico , Oogénesis , Fertilización In Vitro/métodos
2.
Fertil Res Pract ; 4: 3, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29692923

RESUMEN

BACKGROUND: Cancer treatments have significant negative impacts on female fertility, but the impact of cancer itself on fertility remains to be clarified. While some studies have shown that compared with healthy women, those with cancer require higher doses of gonadotropins resulting in decreased oocyte yields, others have shown comparable oocyte yields between the two groups. The purpose of this study is to evaluate whether there is an association between any cancer and/or type of cancer, and response to ovarian stimulation for egg and embryo banking. METHODS: In this retrospective cohort study, ovarian stimulation cycles performed from June 2007 through October 2014 at a single academic medical center were reviewed to identify those undertaken for women with cancer undergoing fertility preservation (n = 147) or women with no cancer undergoing their first cycle due to male factor infertility (n = 664). Of the 147 women undergoing fertility preservation, 105 had local cancer (Stage I-III solid malignancies) and 42 had systemic cancer (hematologic or Stage IV solid malignancies). Response to ovarian stimulation was compared among these two groups and women with no cancer. RESULTS: Adjusting for age and BMI, women with systemic cancer had lower baseline antral follicle counts (AFC) than women with no cancer or local cancer. Women with systemic cancer required higher doses of FSH than women with no cancer or local cancer, and they had higher oocyte to AFC ratios than women with no cancer or local cancer, but greater odds of cycle cancellation as compared to women with no cancer or local cancer. No significant differences were observed among the three groups for duration of stimulation, number of oocytes and mature oocytes retrieved, or number of embryos created. CONCLUSIONS: Women with cancer achieve similar oocyte and embryo yields as women with no cancer, although those with systemic cancer require higher FSH doses and are at greater risk of cycle cancellation.

3.
BJOG ; 124(2): 262-268, 2017 01.
Artículo en Inglés | MEDLINE | ID: mdl-27362908

RESUMEN

OBJECTIVE: To determine if higher-volume, fixed-dose administration of vasopressin further reduces blood loss at the time of minimally invasive myomectomy. DESIGN: Randomised multicentre clinical trial. SETTING: Tertiary-care academic centres in the USA. POPULATION: Women undergoing conventional laparoscopic or robot-assisted laparoscopic myomectomy. METHODS: All participants received the same 10-unit (U) dose of vasopressin, but were randomly assigned to one of two groups: (i) received 200 ml of diluted vasopressin solution (20 U in 400 ml normal saline), and (ii) received 30 ml of concentrated vasopressin solution (20 U in 60 ml normal saline). MAIN OUTCOME MEASURES: The primary study outcome was estimated blood loss; the study was powered to detect a 100-ml difference. RESULTS: A total of 152 women were randomised; 76 patients in each group. Baseline demographics were similar between groups. The primary outcome of intraoperative blood loss was not significantly different, as measured by three parameters: surgeon estimate (mean estimated blood loss 178 ± 265 ml and 198 ± 232 ml, dilute and concentrated groups respectively, P = 0.65), suction canister-calculated blood loss, or change in haematocrit levels. There were no vasopressin-related adverse events. CONCLUSION: Both dilute and concentrated vasopressin solutions that use the same drug dosing demonstrate comparable safety and tolerability when administered for minimally invasive myomectomy; however, higher volume administration of vasopressin does not reduce blood loss. TWEETABLE ABSTRACT: This randomised trial failed to show benefit of high-volume dilute vasopression.


Asunto(s)
Pérdida de Sangre Quirúrgica/prevención & control , Hemostasis Quirúrgica/métodos , Hemostáticos/administración & dosificación , Laparoscopía/métodos , Miomectomía Uterina/efectos adversos , Vasopresinas/administración & dosificación , Adulto , Femenino , Hemostáticos/química , Humanos , Leiomioma/cirugía , Persona de Mediana Edad , Miomectomía Uterina/métodos , Neoplasias Uterinas/cirugía , Vasopresinas/química
4.
J Assist Reprod Genet ; 33(11): 1525-1532, 2016 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-27614634

RESUMEN

PURPOSE: Many practices are moving away from cleavage-stage transfer in favor of blastocyst transfer. The purpose of this study is to evaluate how the overall live birth rate for fresh IVF cycles may increase by optimizing the day of transfer for each patient. METHODS: This is a retrospective cohort study of 1225 first fresh autologous IVF cycles performed between May 2012 and November 2013. Stepwise logistic regression was used to determine characteristics associated with live birth following cleavage-stage versus blastocyst transfer. The optimal transfer day (i.e., the day that maximized the odds of live birth) was determined for each patient, and the actual live birth rate was compared with the projected rate had each patient undergone transfer on her optimal day. RESULTS: With transfer on the optimal day for each patient, the overall birth rate would have increased from its actual value of 34.8 % to a projected 43.0 %, a 24 % increase. The majority of this increase (21 %) was due to optimization of patients who underwent cleavage-stage transfer but had a higher projected birth rate from blastocyst transfer. These patients were older (37.8 versus 36.0 years, p < 0.01) and had more follicles ≥18 mm than patients who should have remained with a cleavage-stage transfer. CONCLUSIONS: A model can be built enabling patient-specific identification of optimal transfer day; within this discovery cohort, such optimization was estimated to increase live birth following a fresh transfer by 24 %. This study suggests blastocyst transfer should be more widely offered; however, there remain patients for whom a cleavage-stage transfer may yield better outcomes.


Asunto(s)
Transferencia de Embrión , Fertilización In Vitro , Nacimiento Vivo/genética , Adulto , Blastocisto/citología , Fase de Segmentación del Huevo/metabolismo , Femenino , Humanos , Embarazo , Índice de Embarazo
5.
J Clin Endocrinol Metab ; 100(9): 3539-47, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-26126208

RESUMEN

CONTEXT: Serum estradiol (E2) levels are preserved in older reproductive-aged women with regular menstrual cycles despite declining ovarian function. OBJECTIVE: The objective of the study was to determine whether increased granulosa cell aromatase expression and activity account for preservation of E2 levels in older, regularly cycling women. DESIGN: The protocol included daily blood sampling and dominant follicle aspirations at an academic medical center during a natural menstrual cycle. SUBJECTS: Healthy, regularly cycling older (36-45 y; n = 13) and younger (22-34 y; n = 14) women participated in the study. MAIN OUTCOME MEASURES: Hormone levels were measured in peripheral blood and follicular fluid aspirates and granulosa cell CYP19A1 (aromatase) and FSH-R mRNA expression were determined. RESULTS: Older women had higher FSH levels than younger women during the early follicular phase with similar E2 but lower inhibin B and antimullerian hormone levels. Late follicular phase serum E2 did not differ between the two groups. Follicular fluid E2 [older (O) = 960.0 [interquartile range (IQR) 765.0-1419.0]; younger (Y) = 994.5 [647.3-1426.5] ng/mL, P = 1.0], estrone (O = 39.6 [29.5-54.1]; Y = 28.8 [22.5-42.1] ng/mL, P = 0.3), and the E2 to testosterone (T) ratio (O = 109.0 ± 41.9; Y = 83.0 ± 18.6, P = .50) were preserved in older women. Granulosa cell CYP19A1 expression was increased 3-fold in older compared with younger women (P < .001), with no difference in FSH-R expression. CONCLUSIONS: Ovarian aromatase expression increases with age in regularly cycling women. Thus, up-regulation of aromatase activity appears to compensate for the known age-related decrease in granulosa cell number in the dominant follicle to maintain ovarian estrogen production in older premenopausal women.


Asunto(s)
Envejecimiento/metabolismo , Aromatasa/metabolismo , Células de la Granulosa/metabolismo , Ciclo Menstrual/metabolismo , Ovario/metabolismo , Adulto , Estradiol/sangre , Femenino , Hormona Folículo Estimulante/sangre , Líquido Folicular/metabolismo , Humanos , Inhibinas , Hormona Luteinizante/sangre , Persona de Mediana Edad , Folículo Ovárico/metabolismo , Receptores de HFE/metabolismo , Testosterona/sangre , Regulación hacia Arriba , Adulto Joven
10.
Minerva Ginecol ; 66(1): 1-11, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24569400

RESUMEN

Although considerable progress has been made in the field of medically assisted reproduction, minimally invasive surgery remains of vital importance in optimizing and preserving fertility, as well as treating infertility. By definition, reproductive surgery employs microsurgical techniques with the objective of restoring natural fertility or enhancing assisted reproductive technologies. The avant-garde minimalist philosophy of this branch of gynecology has made it the natural trailblazer of laparoscopic surgery. Minimally invasive conservative treatment of uterine, tubal, ovarian and peritoneal pathology has long been the gold standard for women of reproductive age and those seeking fertility preservation. Robust surgical outcome data acknowledge clear advantages of advanced laparoscopic surgery over laparotomy. However, this comes at the cost of significant technical challenges. Computer-assisted laparoscopy, also known as robotic surgery, is posed to address the practical limitations of conventional laparoscopic surgery and bridge this technical gap. This enabling technology is a conceptual fusion of the practicality of conventional open surgery and the minimally invasive nature of laparoscopic surgery. With this comes the promise of simplifying complex minimally invasive fertility-sparing procedures so that they can be performed in a safe and reproducible manner by reproductive specialists.


Asunto(s)
Procedimientos Quirúrgicos Ginecológicos/métodos , Microcirugia/métodos , Cirugía Asistida por Computador/métodos , Femenino , Preservación de la Fertilidad/métodos , Humanos , Laparoscopía/métodos , Laparotomía/métodos , Procedimientos Quirúrgicos Mínimamente Invasivos/métodos , Robótica
11.
J Clin Endocrinol Metab ; 99(4): 1384-92, 2014 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-24285681

RESUMEN

CONTEXT: Serum estradiol levels are significantly higher across the menstrual cycle in African American (AAW) compared with Caucasian women (CW) in the presence of similar FSH levels, yet the mechanism underlying this disparity is unknown. OBJECTIVE: The objective of the study was to determine whether higher estradiol levels in AAW are due to increased granulosa cell aromatase mRNA expression and activity. DESIGN: The design of the study included daily blood sampling and dominant follicle aspirations at an academic medical center during a natural menstrual cycle. SUBJECTS: Healthy, normal cycling AAW (n = 15) and CW (n = 14) aged 19-34 years participated in the study. MAIN OUTCOME MEASURES: Hormone levels in peripheral blood and follicular fluid (FF) aspirates and aromatase and FSH receptor mRNA expression in granulosa cells were measured. RESULTS: AAW had higher FF estradiol [1713.0 (1144.5-2032.5) vs 994.5 (647.3-1426.5) ng/mL; median (interquartile range); P < .001] and estrone [76.9 (36.6-173.4) vs 28.8 (22.5-42.1) ng/mL; P < .001] levels than CW, independent of follicle size. AAW also had lower FF androstenedione to estrone (7 ± 1.8 vs 15.8 ± 4.1; mean ± SE; P = .04) and T to estradiol (0.01 ± 0.002 vs 0.02 ± 0.005; P = .03) ratios, indicating enhanced ovarian aromatase activity. There was a 5-fold increase in granulosa cell aromatase mRNA expression in AAW compared with CW (P < .001) with no difference in expression of FSH receptor. FSH, inhibin A, inhibin B, and AMH levels were not different in AAW and CW. CONCLUSIONS: Increased ovarian aromatase mRNA expression, higher FF estradiol levels, and decreased FF androgen to estrogen ratios in AAW compared with CW provide compelling evidence that racial differences in ovarian aromatase activity contribute to higher levels of estradiol in AAW across the menstrual cycle. The absence of differences in FSH, FSH receptor expression, and AMH suggest that population-specific genetic variation in CYP19, the gene encoding aromatase, or in factors affecting its expression should be sought.


Asunto(s)
Aromatasa/genética , Aromatasa/metabolismo , Negro o Afroamericano , Estradiol/sangre , Folículo Ovárico/enzimología , Población Blanca , Adulto , Negro o Afroamericano/genética , Femenino , Líquido Folicular/enzimología , Líquido Folicular/metabolismo , Regulación Enzimológica de la Expresión Génica/fisiología , Células de la Granulosa/enzimología , Células de la Granulosa/metabolismo , Humanos , Ciclo Menstrual/metabolismo , Población Blanca/genética , Adulto Joven
12.
Hum Reprod ; 28(11): 3000-6, 2013 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-24014604

RESUMEN

STUDY QUESTION: What is the relationship between pre-cycle uterine length and IVF outcome (chemical pregnancy, clinical pregnancy, spontaneous abortion and live birth)? SUMMARY ANSWER: Women at extremes of uterine length (<7.0 or >9.0 cm) were less likely to achieve live birth and women with uterine lengths <6.0 cm were also more likely to experience spontaneous abortion. WHAT IS KNOWN ALREADY: A prospective study of 807 women published in 2000 found that implantation and clinical pregnancy rates were highest in women with uterine lengths between 7.0 and 9.0 cm, though the difference was not significant. The relationship between pre-cycle uterine length and live birth has not been evaluated. STUDY DESIGN, SIZE, DURATION: A retrospective cohort study of all cycles performed after uterine length measurement at an academic hospital IVF clinic from 2001 to 2012. PARTICIPANTS/MATERIALS, SETTING, METHODS: A total of 8981 fresh cycles were performed in 5120 adult women with normal uterine anatomy. Women with uterine anomalies (unicornuate, bicornuate, septate or uterus exposed to diethylstilbestrol) were excluded and women with fibroids were identified for subanalysis. Uterine length was measured by uterine sounding. Cycles were divided by uterine length into groups: <6.0 cm (very short, n = 76), 6.0-6.9 cm (short, n = 2014), 7.0-7.9 cm (referent, n = 4984), 8.0-8.9 cm (long, n = 1664) and ≥9 cm (very long, n = 243). Multivariate logistic regression (first-cycle analyses) and generalized estimating equations (all-cycle analyses) were adjusted for age, fibroids and ART treatment (assisted hatching, intracytoplasmic sperm injection) to generate relative risk (RR) of cycle outcomes by uterine length. MAIN RESULTS AND THE ROLE OF CHANCE: Median uterine length in the IVF population was 7.0 cm (interquartile range 7.0-7.8) and was positively associated with BMI (P < 0.001) and fibroids (P = 0.02). Compared with the referent group, women with uterine lengths <6.0 cm were half as likely to achieve live birth (RR: 0.53; 95% confidence interval (CI): 0.35-0.81) and women with lengths of 6.0-6.9 cm were also less likely (RR: 0.91; CI: 0.85-0.98). Cubic regression spline identified a significant inverse U-shaped association whereby women with uterine lengths <7.0 or >9.0 cm were less likely to achieve live birth. Women with lengths <6.0 cm were also more likely to experience spontaneous abortion (RR: 2.16; CI: 1.23-3.78). Results remained consistent when excluding women with a uterine factor diagnosis (n = 8823), when limiting to the first cycle at our institution (n = 5120) and when further restricting to first-ever cycles (n = 3941). LIMITATIONS, REASONS FOR CAUTION: Optimal assessment of uterine length by ultrasound was not feasible due to time and cost limitations, though uterine sounding is a clinically relevant measurement allowing for results with practical implications. Findings from our predominantly Caucasian clinic population may not be generalizable to infertile populations with different ethnic compositions. WIDER IMPLICATIONS OF THE FINDINGS: Reproducibility of results would solidify findings and inform patient counseling in women undergoing IVF. STUDY FUNDING/COMPETING INTEREST(S): No funding was sought for this investigation. MD declares relationships with UpToDate (royalties) and WINFertlity (consultant).


Asunto(s)
Fertilidad , Fertilización In Vitro , Útero/anatomía & histología , Aborto Espontáneo/diagnóstico por imagen , Aborto Espontáneo/epidemiología , Adulto , Índice de Masa Corporal , Femenino , Humanos , Leiomioma/complicaciones , Leiomioma/diagnóstico por imagen , Análisis Multivariante , Tamaño de los Órganos , Embarazo , Resultado del Embarazo , Análisis de Regresión , Estudios Retrospectivos , Factores de Riesgo , Ultrasonografía , Útero/diagnóstico por imagen , Útero/fisiología
13.
J Clin Endocrinol Metab ; 97(1): E106-9, 2012 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-22049179

RESUMEN

CONTEXT: Gonadotropin levels are similar in African-American women (AAW) and Caucasian women (CW), despite higher preovulatory estradiol (E2) levels in AAW, suggesting that AAW may be less sensitive to E2 feedback than CW. OBJECTIVE: The aim of the study was to determine whether responsivity to estrogen feedback differs in AAW and CW. DESIGN AND SETTING: Subjects were studied in the early follicular phase using a 5-d, graded E2 and progesterone infusion. SUBJECTS: Healthy, normal-cycling AAW (n = 10) and CW (n = 13) aged 23-30 yr participated in the study. MAIN OUTCOME MEASURES: Blood samples were collected every 4 h and assayed for LH, FSH, E2, and progesterone. RESULTS: There was no difference in E2-negative feedback on LH (nadir, 3.8 ± 0.4 vs. 5.4 ± 0.9 IU/liter; time of nadir, 33.2 ± 3.3 vs. 32.3 ± 2.7 h) or FSH (nadir, 3.1 ± 0.4 vs. 3.1 ± 0.3 IU/liter; time of nadir, 48.8 ± 2.7 vs. 50.5 ± 3.1 h) in AAW compared to CW. The two groups also demonstrated similar positive feedback responses of E2 on LH (peak, 80.3 ± 13.3 vs. 73.1 ± 11.6 IU/liter; time of peak, 80.4 ± 4.3 vs. 86.5 ± 3.1 h) and FSH (peak, 13.4 ± 1.4 vs. 10.2 ± 1.0 IU/liter; time of peak, 82.2 ± 4.0 vs. 97.2 ± 4.9 h). CONCLUSIONS: LH and FSH feedback responses to a controlled steroid infusion do not differ between AAW and CW, indicating that AAW do not have diminished hypothalamic-pituitary responsivity to E2. These studies support the concept of a threshold effect of E2 in generating LH-positive feedback, suggest pituitary insensitivity to differences in E2 of the magnitude observed in prior studies, and account for similarities in gonadotropins despite E2 differences in AAW compared with CW.


Asunto(s)
Negro o Afroamericano , Estradiol/farmacología , Retroalimentación Fisiológica/efectos de los fármacos , Gonadotropinas/sangre , Población Blanca , Adulto , Índice de Masa Corporal , Estradiol/administración & dosificación , Estradiol/sangre , Femenino , Gonadotropinas/metabolismo , Humanos , Bombas de Infusión , Ciclo Menstrual/sangre , Ciclo Menstrual/efectos de los fármacos , Ciclo Menstrual/metabolismo , Progesterona/administración & dosificación , Progesterona/sangre , Progesterona/metabolismo , Adulto Joven
14.
Am J Physiol Endocrinol Metab ; 301(2): E351-5, 2011 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21558550

RESUMEN

Recent studies have demonstrated an age-related decline in gonadotropins and a decrease in pituitary responsiveness to GnRH, indicating that aging influences the neuroendocrine components of the female reproductive axis independently of changes in ovarian function. To determine whether aging might also affect the luteinizing hormone (LH) negative and positive feedback responses to gonadal steroids, we administered a controlled, graded sex steroid infusion to 11 younger (45-56 yr) and nine older (70-80 yr) postmenopausal women (PMW) in whom endogenous ovarian steroids and peptides are uniformly low. The doses of estradiol (E(2)) and progesterone (P) were chosen to mimic levels across the normal follicular phase and have been shown previously to induce negative followed by positive feedback on LH. Similar E(2) and P levels were achieved in younger and older PMW (P = 0.4 and 0.3, respectively) and produced a biphasic LH response in all subjects. The early decline in LH to 53% of baseline was not different in older vs. younger PMW. However, the positive feedback effect was attenuated in older compared with younger PMW (peak LH 144.4 ± 19.5 vs. 226.8 ± 22.3 IU/l, respectively, P = 0.01). In conclusion, these studies in PMW demonstrate preservation of short-term steroid negative and positive feedback in response to exogenous E(2) and P with aging. Attenuation of positive feedback in older compared with younger PMW is consistent with previous reports of declining GnRH responsiveness with aging.


Asunto(s)
Envejecimiento/metabolismo , Estradiol/administración & dosificación , Terapia de Reemplazo de Estrógeno/métodos , Retroalimentación Fisiológica/efectos de los fármacos , Progesterona/administración & dosificación , Factores de Edad , Anciano , Anciano de 80 o más Años , Estradiol/metabolismo , Retroalimentación Fisiológica/fisiología , Femenino , Fase Folicular/efectos de los fármacos , Fase Folicular/fisiología , Hormona Liberadora de Gonadotropina/metabolismo , Humanos , Hormona Luteinizante/metabolismo , Persona de Mediana Edad , Progesterona/metabolismo
15.
J Clin Endocrinol Metab ; 95(4): 1955-61, 2010 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-20133465

RESUMEN

CONTEXT: Studies in humans and animals indicate that estrogen negative feedback occurs at the level of the hypothalamus, but it is unclear whether estrogen also exerts an inhibitory effect directly at the pituitary. OBJECTIVES: The aim of the study was to determine whether estrogen has a direct negative feedback effect at the pituitary and whether this varies with aging. DESIGN AND SETTING: A GnRH antagonist and graded doses of GnRH were used to isolate pituitary responsiveness before and after estrogen administration in Clinical Research Center studies at an academic medical center. SUBJECTS: Subjects were healthy postmenopausal women aged 48-56 yr (n = 8) or 70-75 yr (n= 8). INTERVENTIONS: A suppressive dose of the NAL-GLU GnRH antagonist was administered, followed by graded doses of GnRH before and after 1 month of estrogen administration. RESULTS: LH and FSH responses to GnRH decreased after estrogen administration (P = 0.01 and P = 0.0001, respectively). The ratio of FSH to LH amplitudes decreased in response to estrogen (P = 0.04) indicating a greater sensitivity of FSH than LH to inhibition by estrogen. The inhibitory effect of estrogen on FSH was attenuated with aging (P = 0.02), but was maintained for LH (P = 0.4). CONCLUSIONS: Studies that control for endogenous GnRH and estradiol demonstrate a direct pituitary site of estrogen negative feedback on LH and FSH responsiveness to GnRH in women. The effect of estrogen on FSH responsiveness is greater than on LH and is attenuated with aging. These studies indicate that estrogen negative feedback occurs directly at the pituitary and contributes to the differential regulation of FSH and LH secretion.


Asunto(s)
Estrógenos/fisiología , Retroalimentación Fisiológica/fisiología , Gonadotropinas/metabolismo , Hipófisis/fisiología , Administración Cutánea , Adulto , Anciano , Envejecimiento/fisiología , Relación Dosis-Respuesta a Droga , Estradiol/administración & dosificación , Estradiol/farmacología , Terapia de Reemplazo de Estrógeno , Estrógenos/farmacología , Femenino , Hormona Folículo Estimulante/sangre , Hormona Liberadora de Gonadotropina/antagonistas & inhibidores , Hormona Liberadora de Gonadotropina/farmacología , Humanos , Hormona Luteinizante/sangre , Persona de Mediana Edad , Hipófisis/metabolismo
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