Mechanism of action of gestagens

Landgren, Britt-Marie

doi:10.1016/0020-7292(90)90473-x

Cited by 8 publications

(3 citation statements)

References 78 publications

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“…These effects include alteration of cervical mucous and the endometrium that adversely impact sperm migration and embryo implantation respectively (24). Up to 40% of women using the progestin-only OCPs can ovulate (23)(24)(25)(26). Thus, the 60% reduction in ovarian cancer from a progestin-only OCP is further evidence that progestins have a direct chemopreventive effect on the ovary.…”

Section: Discussionmentioning

confidence: 80%

Evidence of a Chemopreventive Effect of Progestin Unrelated to Ovulation on Reproductive Tract Cancers in the Egg-laying Hen

Rodriguez¹,

Barnes²,

Anderson³

et al. 2013

Cancer Prev Res

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Epidemiologic, laboratory, and animal evidence suggests that progestins and vitamin D may be potent ovarian cancer preventives. Our objectives were to evaluate progestins as reproductive tract cancer chemopreventives in the chicken, determine whether restricted ovulation affected the incidence of reproductive tract tumors, and assess whether vitamin D would confer cancer protection either alone or in addition to progestin. A total of 2,400 two-year-old Single Comb White Leghorns were randomized into six groups (400 each) with hormonal and dietary manipulation for 2 years as follows: (i) no intervention, regular feed/caloric intake, (ii) control, (iii) vitamin D, (iv) the progestin levonorgestrel, (v) vitamin D plus levonorgestrel, and (vi) the progestin Provera (medroxyprogesterone acetate). Groups 2 to 6 were caloric restricted to inhibit ovulation. Our results indicated that caloric restriction decreased egg production by more than 60%, and was associated with a greater than 70% decrease in reproductive tract cancers. Ovulatory events did not differ among the caloric-restricted groups (groups 2-6), except for the group receiving levonorgestrel, which had fewer ovulatory events than controls (P ¼ 0.046). After correcting for egg production, birds receiving progestins had significantly fewer reproductive tract cancers [OR, 0.61; confidence interval (CI), 0.39-0.95; P ¼ 0.03], with similar proportionate reductions in tumors arising in either the ovary or oviduct. Vitamin D did not significantly affect cancer incidence overall, or add to the cancer preventive effect of progestins. This study suggests a protective effect of progestins against ovarian and oviductal cancers. These data support the concept that progestins provide a chemopreventive effect unrelated to ovulation. Cancer Prev Res; 6(12); 1283-92. Ó2013 AACR.

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Section: Discussionmentioning

confidence: 80%

Evidence of a Chemopreventive Effect of Progestin Unrelated to Ovulation on Reproductive Tract Cancers in the Egg-laying Hen

Rodriguez¹,

Barnes²,

Anderson³

et al. 2013

Cancer Prev Res

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“…Los estrógenos y los gestágenos a grandes dosis pueden inhibir por sí solos la ovulación y utilizados en conjunto, su efecto sinérgico permite disminuir la dosis de cada uno (6). La inhibición sobre el eje hipotálamo-hipófisis es dosis dependiente, a menores dosis, los niveles basales de gonadotrofinas son mayores (7,8). Considerando los ACO que poseen etinilestradiol (EE2) y levonorgestrel (LNG) como progestágeno, ha habido una reducción de las dosis de ambos compuestos pasando de 50 µg EE2 / 250 µg LNG a las dosis actuales de 30 µg EE2 / 150 µg LNG.…”

Section: Introduccionunclassified

Mecanismo De Accion De Anticonceptivos Orales: ¿cumplen Los Aco De Bajas Dosis Con El Objetivo De Inhibir La Ovulacion?

C.¹,

Preisler²,

Poli³

2002

Rev. chil. obstet. ginecol.

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RESUMENLa inhibición de la ovulación es el principal mecanismo o efecto buscando en los casos de utilización terapéutica o contraceptiva de los anticonceptivos orales (ACO). Los mecanismos de acción secundarios postfertilización tienen reparos éticos para aquellas pacientes que consideran la concepción como el comienzo del desarrollo de la persona humana. Quisimos saber en qué medida se inhibe la ovulación mediante la administración de ACO de bajas dosis, como primera aproximación al problema ético planteado por los efectos postfertilización y para analizar la eficacia terapéutica de los anticonceptivos orales. Se revisa la literatura entre los años 1985 y 2001 y se seleccionan tres trabajos comparables entre sí de los cuales se desprenden los resultados. En un período de seguimiento de tres meses, las mujeres que ingieren en forma adecuada ACO monofásicos combinados de bajas dosis que contienen 20 µg de etinilestradiol, presentan ovulación demostrada hormonal y ecográficamente en 2,35% a 8,3% de las mujeres. Existe una tendencia al aumento de la actividad ovárica y de los diámetros foliculares a medida que transcurre el tiempo de observación. Si el objetivo terapéutico es la anovulación, estas cifras permiten considerar los ACO como terapias adecuadas. Frente a la utilización individual de los ACO en contracepción, las cifras expuestas permitirán abordar en qué medida actúan los mecanismos secundarios y así considerar parámetros más objetivos en el análisis de los aspectos éticos a evaluar por el médico y la paciente. PALABRAS CLAVES: Anticonceptivos de bajas dosis SUMMARYOral contraceptives (OCs) may be used for therapeutic or family planning purposes. Inhibition of ovulation is the main mechanism implicated in both instances, though post-fertilization effects described as secondary mechanism in effective contraception are ethically unacceptable for some patients who identify the start of human person at fertilization. Our concern was to establish the anovulatory power of low dose OCs in attempting to answer the ethical question and secondarily to evaluate their therapeutic efficacy. Literature search of articles published from 1985 through december 2001 using Medline concluded with 15 articles (meaningful to this theme) who met inclusion criteria: low dose monophasic preparation containing 0.20 mg ethinylestradiol, ovulation assessed by means of hormonal and transvaginal ultrasound monitoring and the trial carried out over a period of at least three treatment cycles. Three studies are analized. We conclude that in 2.35% to 8% of women, ovulation was confirmed.This results indicate that low-dose

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“…The GnRH‐agonist nafarelin in the dose of 200 μg twice daily completely down‐regulates the ovaries in almost all cases, although sparse bleedings may occur (5). The dosage of the gestagen MPA used for the treatment of endometriosis has been very different in different studies, but 30 mg daily is the minimum dose of MPA that inhibits ovulation completely and the effect on the ovarian function should thus be comparable to that of nafarelin (6). Also Moghissi and Boyce (7) and Roland et al (8) used the dosage of 30 mg MPA for treatment of endometriosis.…”

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confidence: 99%