Actions of progestins on the morphology and biochemistry of the endometrium of postmenopausal women receiving low-dose estrogen therapy

Progesterone and endometrial cancer

It is well established that unopposed estrogen, either endogenous or therapeutic, can induce endometrial hyperplasia and potentially endometrial cancer (EC). Anovulatory cycles, obesity, and insulin resistance are major risk factors for EC. Progestogen (progesterone and progestin), including levonorgestrel intrauterine device, are able to prevent or to treat hyperplasia, atypical hyperplasia, and even well-differentiated EC, as presented in this review. During menopausal hormone therapy, progestogens protect the endometrium against the proliferative effects of estrogens in women with a uterus. Whereas, recent epidemiologic data suggest that micronized progesterone (MP) is apparently safer for the breast, it could be less efficient than synthetic progestin on the endometrium. However, several studies from biopsies during treatment with MP do not show any increased risk of hyperplasia. Lack of compliance could explain the results on EC.

Association of estrogen and progestin potency of oral contraceptives with ovarian carcinoma risk

OBJECTIVE

To estimate the association of the estrogen and progestin potency of combined oral contraceptive pills (OCPs) with epithelial ovarian carcinoma risk.

METHODS

This population-based case-control study included 745 women with incident, histologically confirmed epithelial ovarian carcinoma and 943 controls, matched on age and ethnicity. Data were collected using a standard questionnaire, picture albums, and calendars. The association of OCP potency with epithelial ovarian carcinoma risk was modeled using unconditional logistic regression.

RESULTS

When compared with women who never used hormonal contraception, users of OCPs with low estrogen (equal to or less than 0.035 mg ethinyl estradiol) and low progestin (less than 0.3 mg norgestrel) were at significantly reduced risk of ovarian carcinoma (odds ratio 0.19; 95% confidence interval 0.05-0.75). The risk among these women was lower than among users of estrogen or progestin of high potency, but the difference was not statistically significant. However, in a subset of 205 women who reported exclusive use of norethindrone, users of 0.5 mg or less, had a significantly reduced risk of ovarian cancer compared with women using 10 mg of this progestin. Increased norethindrone dose resulted in a significant increase in ovarian carcinoma risk, indicating a dose-response association.

CONCLUSION

Combined OCPs were effective at decreasing the risk of epithelial ovarian carcinoma, with the strongest risk reduction associated with low-potency formulations.

LEVEL OF EVIDENCE

II.

Histological and immunohistochemical evaluation of postmenopausal endometrium after 3 weeks of treatment with tibolone, estrogen only, or estrogen plus progestagen

OBJECTIVE

To evaluate histological and immunohistochemical parameters of short-term (21 days) tibolone, estrogen-only, and estrogen+progestagen treatment in the human postmenopausal endometrium.

DESIGN

An observational, open, nonrandomized, controlled study.

SETTING

Three collaborating centers: Amphia Hospital in Breda, Albert Schweitzer Hospital in Dordrecht, Erasmus Medical Center in Rotterdam, the Netherlands.

PATIENT(S)

Thirty healthy, postmenopausal women.

INTERVENTION(S)

Control group (n = 9), no hormonal treatment; tibolone group (n = 8), patients were treated with 2.5 mg of tibolone (administered orally) every day, starting 21 days before surgery; estrogen group (n = 7), patients were treated with 2 mg of E(2) (Zumenon, administered orally; Zambon, Amerfoort; The Netherlands) every day, starting 21 days before surgery; estrogen+progestagen group (n = 6), patients were treated with 2 mg of E(2) (Zumenon, administered orally) and 5 mg of medroxyprogesterone acetate (administered orally) every day, starting 21 days before surgery.

MAIN OUTCOME MEASURE(S)

Uterine tissues were collected, and two pathologists independently assessed histology. Immunohistochemical parameters measured were estrogen receptor alpha, progesterone receptor A/B, Hoxa10, Ki67, and Bcl-2.

RESULT(S)

On the basis of a number of histological and immunohistochemical parameters measured after 21 days of treatment, it was observed that tibolone displays clearly less stimulation (proliferation) of the human postmenopausal endometrium than estrogen at the beginning of a treatment, but the stimulation is higher than with estrogen+progestagen.

CONCLUSION(S)

Short-term (21 days) tibolone treatment results in a small stimulation of proliferation of the endometrium, and because long-term treatment with tibolone has been demonstrated to lead to an atrophic endometrium, it may be concluded that the stimulatory effect, as observed in this study, is transient in nature. It is hypothesized that tibolone first displays a more estrogenic mode of action, which over time, is counterbalanced by the induction of its progestagenic properties.

Postmenopausal hormone therapy and breast cancer: a systematic review and meta-analysis

OBJECTIVE

There is a rapidly evolving debate on the indications and appropriate duration of therapy for postmenopausal hormone therapy. The objective of this meta-analysis was to examine the specific relationships of postmenopausal estrogen therapy (ET), postmenopausal combined (estrogen-progestogen) hormone therapy (CHT), and the incidence of breast cancer.

DESIGN

We performed computerized searches of MEDLINE and CancerLit through September 2003 and reviewed reference lists of retrieved studies and meta-analyses. We included English-language studies that identified noncontraceptive postmenopausal hormone use; reported on the risks of "current use" of ET and/or CHT and breast cancer incidence; were case-control, cohort, or experimental; and reported either an odds ratio (OR), relative risk (RR), or HR with CIs. Two investigators were involved during all stages of study selection and independently extracted all data selected for inclusion in meta-analyses.

RESULTS

Meta-analysis of 13 studies of ET and breast cancer (700,000 women) resulted in an OR of 1.16 (95% confidence limits [CL] 1.06, 1.28), with estimates for less than 5 years use 1.16 (1.02, 1.32) and more than 5 years use 1.20 (1.06, 1.37). Meta-analysis of eight studies of CHT and breast cancer (650,000 women) resulted in an OR of 1.39 (95% CL 1.12, 1.72), with estimates for less than 5 years use 1.35 (1.16, 1.57) and more than 5 years use 1.63 (1.22, 2.18).

CONCLUSIONS

Data from observational studies support the association of increased but considerably different risks for breast cancer incidence among current users of ET and CHT. These represent the first pooled estimates for ET. CHT estimates correspond to those from randomized trials.

Effect of medroxyprogesterone acetate on vascular inflammatory markers in postmenopausal women receiving estrogen

BACKGROUND

Estrogen increases C-reactive protein (CRP) in postmenopausal women. Estrogen also decreases cell adhesion molecules, whereas elevated CRP stimulates the expression of cell adhesion molecules. Because androgens have antiinflammatory effects, androgenic progestins such as medroxyprogesterone acetate (MPA) may inhibit proinflammatory effects of estrogen. We investigated the effects of MPA on estrogen-induced changes in acute inflammatory proteins and cell adhesion molecules in postmenopausal women.

METHODS AND RESULTS

Postmenopausal women were treated daily with conjugated equine estrogen (CEE, 0.625 mg), CEE plus MPA 2.5 mg, or CEE plus MPA 5.0 mg for 3 months. CEE significantly increased CRP concentrations by 320.1+/-210.2% (P<0.05). The addition of MPA to CEE, however, inhibited the increase in CRP in a concentration-dependent manner (MPA 2.5 mg, 169.8+/-66.9%, P<0.05; MPA 5 mg, 55.0+/-30.4%, not significant). Similarly, CEE increased amyloid A protein concentrations, whereas MPA reversed this effect. Interleukin-6 concentration did not change significantly in any treatment group. CEE alone significantly decreased the concentration of E-selectin, but the concentrations of intercellular adhesion molecule and vascular cellular adhesion molecule did not change significantly. The addition of MPA tended to decrease the levels of cell adhesion molecules, and use of 5.0 mg MPA showed significant decreases in all cell-adhesion molecule concentrations.

CONCLUSIONS

Concurrent MPA administration may attenuate estrogen's proinflammatory effect. Because MPA in combination with CEE decreased cell adhesion molecule concentrations, the anti-inflammatory effect of MPA may actually be responsible for the favorable effect of estrogen-progestogen combinations on cell adhesion molecules in postmenopausal women.

Effect of medroxyprogesterone acetate on endothelium-dependent vasodilation in postmenopausal women receiving estrogen

BACKGROUND

Estrogen increases endothelium-dependent vasodilation in postmenopausal women. However, use of progestins in combination with estrogen may counter beneficial effects of estrogen on endothelium. We investigated the effect of medroxyprogesterone acetate (MPA) on estrogen-induced increase in endothelium-dependent vasodilation in postmenopausal women.

METHODS AND RESULTS

Postmenopausal women were treated daily with conjugated equine estrogen (CEE) 0.625 mg (n=14), CEE 0.625 mg and MPA 2.5 mg (n=15) or CEE 0.625 mg and MPA 5.0 mg (n=16) for 3 months. Plasma lipids and hormones were measured before and after treatment. Vasodilatory responses of the brachial artery were evaluated by measuring flow-mediated vasodilation (FMD) and nitroglycerin-induced vasodilation by use of high-resolution ultrasonography. Susceptibility of LDL to oxidation was analyzed by incubation with CuSO(4) while kinetics of conjugated diene formation was monitored. Plasma total and LDL cholesterol concentrations were decreased significantly in all groups. CEE increased FMD significantly, from 4.5+/-1.7% to 8.5+/-2.8% (P<0.001). Addition of MPA reversed this effect in a concentration-dependent manner (for MPA 2.5 mg, from 5.0+/-3.2% to 6.2+/-3.1%; for MPA 5.0 mg, from 4.9+/-3.4% to 3.6+/-3.7%; P=NS for each). No treatment significantly altered nitroglycerin-induced dilation. Lag time for conjugated diene formation was prolonged significantly in all groups, and the oxidation rate was significantly reduced.

CONCLUSIONS

Concurrent MPA administration may offset favorable effects of estrogen on endothelial function in postmenopausal women. Because MPA did not diminish LDL-lowering and antioxidant effects of estrogen, MPA-induced inhibition of endothelium-dependent vasodilation may be independent of changes in oxidative susceptibility and plasma concentration of LDL.

Ultrasonographic and morphological studies of the postmenopausal endometrium using unopposed estrogen replacement therapy with regular pause: a prospective preliminary study

Hormone replacement therapy with progestogen is known to have severe side effects or complications in certain patients.

OBJECTIVE

The goal of this study is to evaluate the safety and efficacy of an alternative treatment regimen with a mensal pause using both transvaginal sonography (TVS) and endometrial biopsy to follow patients.

METHODS

A total of 30 postmenopausal women were treated with unopposed estrogen for 21 days each month followed by a regular pause of 9-10 days, and were studied prospectively for 18 months. The TVS measurements of endometrial thickness and biopsy of the endometrium were done on the 21st day of treatment and the 7th day of the pause at 6-month intervals throughout the study.

RESULTS

There was a significant decrease of proliferative activity at all three time points during the study (6, 12 and 18 months) when tested on the 7th pause day (PD7). The percentage of patients with hyperplasia without nuclear atypia and endometrial thickness > or =8mm was 32% at 6 months, but decreased to 22 and 19% at 12 and 18 months, respectively. All cases of hyperplasia regressed after the hormonal pause throughout the treatment period.

CONCLUSIONS

This study presents an alternative treatment regimen for select patients having side effects or complications from progestogen administration; however, studies evaluating the safety and efficacy of this regimen over longer time periods are necessary.

Hormonal pathology of the endometrium

The endometrial tissue is a sensitive target for steroid sex hormones and is able to modify its structural characteristics with promptness and versatility. This article discusses briefly endogenous hormonal effects (cyclic changes, luteal phase defect, unopposed estrogen effect) and describes the histologic patterns encountered in the most commonly used hormone therapies: oral contraceptives, ovulation stimulation, hormone replacement therapy, and antitumoral hormone therapy. Oral contraceptives exert a predominant progestational effect on the endometrium, inducing an arrest of glandular proliferation, pseudosecretion, and stromal edema followed by decidualized stroma with granulocytes and thin sinusoidal blood vessels. Prolonged use results in progressive endometrial atrophy. Ovulation induction therapy accelerates the maturation of the stroma and is often associated with a discrepancy between early secretory glands and an edematous or decidualized stroma with spiral arterioles. Hormone replacement therapy with estrogen alone may result in continuous endometrial proliferation, hyperplasia, and neoplasia. The use of both estrogen and progesterone elicits a wide range of histologic patterns, seen in various combinations: proliferative and secretory changes, often mixed in the same tissue sample; glandular hyperplasia (in polyps or diffuse) ranging from simple to complex atypical; stromal hyperplasia and/or decidual transformation; epithelial metaplasia (eosinophilic, ciliated, mucinous); and inactive and atrophic endometrium. Progesterone therapy for endometrial hyperplasia and neoplasia induces glandular secretory changes, decidual reaction, and spiral arterioles. Glandular proliferation is usually arrested, but neoplastic changes may persist and coexist with secretory changes. Lupron therapy produces a shrinking of uterine leiomyomas by accelerating their hyaline degeneration, similar to that in postmenopausal involution. It generally produces endometrial atrophy. Tamoxifen for breast carcinoma has an estrogen agonist effect on the uterus in approximately 20% of patients, who develop endometrial polyps, glandular hyperplasia, adenomyosis, and/or leiomyomata. Both endometrioid and nonendometrioid carcinomas are seen, often in polyps. Their causal relationship to tamoxifen therapy is debatable.

Effects of continuous medroxyprogesterone acetate on lipoprotein metabolism in postmenopausal women receiving estrogen

OBJECTIVE

To investigate the effects of medroxyprogesterone acetate (MPA) on the beneficial effects of estrogen therapy on lipid metabolism in postmenopausal women.

METHODS

Postmenopausal women were administered either conjugated equine estrogen (CEE) 0.625 mg daily for 3 months (Group 1) or CEE 0.625 mg in conjunction with MPA 2.5 mg (Group 2) or MPA 5.0 mg (Group 3) daily for 3 months. Plasma levels of cholesterol, triglyceride, lipoprotein lipids, apolipoproteins, sex steroid hormones and lecithin cholesterol acyltransferase activity (LCAT) were determined. Lipoprotein lipase (LPL) and hepatic triglyceride lipase (H-TGL) activities were measured in postheparin plasma. Changes in the lipid concentrations and enzymatic activities were evaluated in each group.

RESULTS

Total, low-density lipoprotein (LDL) cholesterol, apolipoprotein B concentrations and LCAT activity were all significantly reduced by treatment in the three groups. The levels of high-density lipoprotein (HDL), HDL2, and HDL3 cholesterol as well as the levels of apolipoprotein AI and AII were significantly elevated in groups 1 and 2. The mean decrease in these parameters was related to the dose of MPA. Levels of triglyceride in the HDL and HDL2 were significantly increased in group 1. The levels of triglyceride in plasma, very low density lipoprotein (VLDL), LDL, HDL3 and VLDL cholesterol and LPL activity were unaffected. H-TGL activity was significantly inhibited only in groups 1 and 2. MPA produced a dose-dependent increase in H-TGL activity. A significant negative correlation was observed between the HDL cholesterol concentration and H-TGL activity (r = 0.58 P < 0.001).

CONCLUSIONS

The administration of MPA 2.5 mg and 5.0 mg did not adversely affect the changes in VLDL-LDL metabolism produced by estrogen. However, MPA has dose-dependent negative effects on HDL metabolism by increasing H-TGL activity and the 5.0 mg MPA interferes with the favorable effects on lipids of estrogen in postmenopausal women.

Inhibitory effects of medroxyprogesterone acetate on mouse endometrial carcinogenesis

The present study was undertaken to examine the effects of cyclic administration of low-dose progestogen on endometrial carcinogenesis in mice. A total of 115 female ICR mice, 10 weeks of age, were divided into four experimental and control groups. Mice in groups 1-3 received laparotomy and were injected with N-methyl-N-nitrosourea (MNU) solution at a dose of 1 mg/100 g body weight to the left uterine tube and with normal saline to the right uterine tube. From one week after the MNU exposure, groups 1 and 2 were given 5 ppm 17 beta-estradiol (E2)-containing diet throughout the experiment. Mice in group 1 received 5 s.c. injections of medroxyprogesterone acetate (MPA) (2 mg/mouse) at intervals of 4 weeks from week 7. Group 3 was treated with MNU/normal saline alone. Group 4 consisted of mice treated with MPA alone. At the termination of the experiment (week 30), all animals were killed and autopsied for pathological examinations. It was found that adenocarcinomas and preneoplastic lesions developed in the bilateral uterine corpora in mice of groups 1-3. MPA treatment significantly decreased the weight of the uterine corpus (P < 0.05) and the incidences of endometrial adenocarcinoma and atypical or adenomatous (P < 0.001) but not cystic glandular hyperplasias in the MNU/E2-treated groups. Additionally, MPA treatment tended to decrease the proliferating cell nuclear antigen-labeling index in endometrial glandular cells. These data indicate that MPA, even at low dose, has an inhibitory effect on mouse endometrial carcinogenesis induced by MNU and E2.

Endometrial response in sequential cyclic therapy assessed with associated hysteroscopy and histology

A morphologic study was performed on the endometrium in 37 asymptomatic postmenopausal women under effects of cyclically administered oestrogens. Eighty-seven postmenopausal women were taken as control group. Medroxyprogesterone acetate (MPA), 10 mg daily, was administered in association with two types of oestrogen replacement therapy: conjugated equine oestrogens 0.625 mg (CEE) or transdermal 17 beta-oestradiol 0.05 mg (E2-TTS). Endometrial biopsies were taken under hysteroscopic control before treatment and on days 8-12 of combined therapy at the 6th month. Follow-up at 12 and 18 months was only performed in 8 and 5 patients, respectively, with transdermal 17 beta-oestradiol treatment. Various types of endometrial response were identified from atrophy to hyperplasia and secretory patterns. No atypical hyperplasia was found. All cases of simple or complex hyperplasia showed a regression after increased MPA dosage treatment (20 mg). This work is aimed at investigating the endometrial response during sequential cyclic therapy by using morphologic criteria based on hysteroscopy and histology. A large number of patients with hyperplasia can be detected with target biopsy under hysteroscopy, thus playing an important role in the management of patients during replacement therapy in research protocols.

Progestogens: therapeutic and adverse effects in early post-menopausal women

Progestogen treatment is associated with a number of subjective symptoms. In the present study, 148 healthy post-menopausal women suffering from mild climacteric symptoms were randomly allocated to 12 weeks of treatment with (a) 2 mg oestradiol valerate combined with cyproterone acetate, medroxyprogesterone acetate or levonorgestrel; (b) 1.5 mg 17 beta-oestradiol combined with desogestrel; or (c) placebo. Climacteric symptoms, Kupperman index scores and potential adverse progestogen effects were recorded before treatment and three times per month during therapy. All the hormone regimens had a rapid effect, reducing the severity of climacteric symptoms to about 30% of the baseline values (P less than 0.001) within one month. Hot flushes were reduced in severity and/or frequency by 76 100% within 3 months (P less than 0.001). The regimens which included hydroxyprogesterone derivatives produced a transient increase in breast tenderness. Other recorded potential adverse progestogen effects showed no significant changes during the study. We concluded that the addition of progestogens (whether 19-nortestosterone or hydroxyprogesterone derivatives) does not produce significant side effects during combined hormone replacement therapy.

Effects of post-menopausal oestrogen-progestogen replacement therapy on serum lipids and lipoproteins: a review

There are strong indications that post-menopausal oestrogen replacement therapy has a protective effect on the cardiovascular system, due to changes in the lipid profile. There are also indications that the addition of progestogens to oestrogen therapy may negatively influence these effects on the lipid metabolism. The present survey was undertaken to provide a comprehensive summary of all the available data on the effect of combined oestrogen-progestogen treatment on the post-menopausal lipid profile published from 1984 onwards. It appears that many progestogens are capable of diminishing the beneficial changes induced by oestrogens. The ultimate effect depends on the type and daily dose of both the oestrogen and the progestogen component. Oestradiol or oestradiol valerate administered cyclically with progesterone or cyproterone acetate appear to have the most favourable impact on lipids and lipoproteins.

The optimal dose of oral norethindrone acetate for addition to transdermal estradiol: a multicenter study

The effects of adding one of three doses (0.5, 0.75, or 1.0 mg/d) of norethindrone acetate for 12 days each month to continuous, transdermal estradiol (0.05 mg/d) have been determined in a prospective, randomized, multicenter study. Significant symptomatic and psychological improvements were observed and, with one exception, were not opposed by the added progestogen. Distinct redness at the site of last patch application was reported by 10% of patients and faint erythema by 30%. However, less than 5% of patients discontinued treatment because of skin problems. Breakthrough bleeding occurred infrequently and all three doses of norethindrone acetate induced a regular pattern of bleeding with secretory transformation in the endometrium. There was no hyperplasia or carcinoma.

Are fixed-dose oestrogen/progestogen combinations ideal for all HRT users?

Although progestogens protect the endometrium against excessive oestrogen-induced stimulation, they can cause adverse symptomatic and psychological effects and may have undesirable metabolic consequences. Thus, the minimum progestogen dose which results in consistent endometrial transformation should be prescribed. To define this dose for norethisterone and dl-norgestrel, 197 endometrial samples obtained from postmenopausal women receiving conjugated equine oestrogens (0.625 mg or 1.25 mg daily) with one of six doses of norethisterone (or the acetate), or one of three doses of dl-norgestrel added for the first 12 days of each calendar month were examined with the light microscope; 109 samples were also assessed by transmission electron microscopy. There was an inverse relation between the percentage of samples showing proliferative features and the progestogen dose. However, proliferative endometrium was observed in 6% of samples with the highest dose of dl-norgestrel (500 micrograms) and in 3% of samples with 2.5 mg norethisterone. Conversely, complete secretory transformation was observed in 25% of samples with the lowest dose of norethisterone (0.1 mg) and in 40% of samples with 75 micrograms dl-norgestrel. Mild atypical hyperplasia was diagnosed in four samples. There was a wide inter-patient variation in response and none of the nine progestogen dose regimens induced secretory change in every patient.

The effects of the addition of nomegestrol acetate to post-menopausal oestrogen therapy

Progestogens are added to the oestrogen treatment for 10-12 days each cycle in order to prevent endometrial abnormalities. However, concern has been expressed about the safety of certain of the currently available progestogens because of the potential adverse metabolic effects. We have evaluated the effects of nomegestrol acetate - non-androgenic progestogen - for administration to post-menopausal oestrogen users. Thirty-six (36) women receiving 50 mg oestradiol implants at regular intervals also took nomegestrol acetate for 12 days each calendar month at doses of 0.5 mg, 1.0 mg and 2.5 mg daily. Allocation to one of the dose regimens was random. Physical and psychological side-effects were recorded and all vaginal bleeding was noted: an endometrial biopsy was performed on the sixth day of progestogen addition for histological, ultrastructural and biochemical evaluation. Adverse side-effects were responsible for a dose-dependent drop out rates of 17%. All patients experienced a regular, progestogen-induced withdrawal bleed each month; and histological, ultrastructural and biochemical changes were induced within the endometrium by all 3 doses. Nomegestrol acetate is a potent progestogen and further studies are required to determine its lowest effective dose.

Basement membrane components in normal hyperplastic and neoplastic endometrium

The major basement membrane (BM) components, laminin and type IV collagen, were studied by immunochemistry in normal, hyperplastic, and neoplastic endometrium. By immunoperoxidase technique, proliferative and secretive endometrium showed capillary and epithelial cell basement membranes with linear staining with antibodies to both laminin and type IV collagen. Immunostaining of laminin and type IV collagen showed that capillaries were surrounded by a continuous perivascular sheath of these matrices in specimens of adenomatous hyperplasia and in nearly all specimens of endometrial adenocarcinoma. Laminin and type IV collagen were found to accumulate around glandular epithelial cells of adenomatous hyperplastic endometrium, but in several specimens these linear surrounding formations were defective and discontinuous. In several areas of well-differentiated endometrial adenocarcinomas BM-like structures were found around glandular epithelial cells as shadows without staining for laminin and type IV collagen. These basement membrane components accumulate around stromal cells to encircle each cell with a gradual, progressive, and cyclic process depending on the phase of the menstrual cycle. Laminin and type IV collagen were clearly detected around stromal cells at days 20 to 22 of the menstrual cycle and more thickly at days 26 to 28. The accumulation of these matrices around stromal cells is a progesterone/progestin-related process. In the well-differentiated adenocarcinoma a mid-term treatment with progestin (Danatrol Maggioni-Winthrop, SPA, Milan, Italy) was found to be effective on laminin and type IV collagen accumulation around stromal cells.

Progesterone challenge test in postmenopausal women with pathological endometrium

Cytosolic and nuclear progesterone receptor levels (RPC, RPN) were measured in normal and in pathological human endometria after single-dose progesterone injection 1-3 h before tissue collection (test subjects) and the results compared to those obtained in controls (no progesterone treatment). In test cases of late proliferative or midcycle normal endometria and in estrogen-primed normal postmenopausal endometria, RPN levels were higher and RPC levels were lower compared with those obtained in control samples. In test cases of postmenopausal pathological endometria, histologically normal endometria of women with postmenopausal bleeding and in one case of endometrial polyp, RPN levels were also higher and RPC levels lower than those in the respective controls, but the change of distribution of the RP (cytosol/nuclear extract) was significantly lower than in normal endometrium.

Continuous estrogen/progestin therapy in menopause

The incidence of vaginal bleeding, endometrial histology, menopausal symptoms, blood pressure, and serum lipid concentrations were evaluated in 26 women who received either continuous conjugated equine estrogens and medroxyprogesterone acetate (group I, N = 16) or cyclic conjugated equine estrogen + medroxyprogesterone acetate (group II, N = 10) over a 9-month treatment period. At the end of therapy, endometrial biopsy specimens in group I revealed inactive endometrium, whereas one of ten biopsy specimens in group II showed proliferative endometrium. Blood pressure, serum total cholesterol, high-density and low-density lipoprotein cholesterol, and triglyceride levels were not significantly altered from baseline in either group during the 9-month treatment. Vaginal bleeding was virtually eliminated in group I by the end of the study, while 80% of the patients in group II continued to have cyclic menses (p less than 0.001). This pilot study suggests that continuous conjugated equine estrogen plus medroxyprogesterone acetate therapy appears to be a satisfactory method of postmenopausal hormone replacement, effectively reducing menopausal symptoms without any apparent short-term alterations in serum lipids. It has the added benefit of eliminating cyclic menstrual flow.

Progesterone (P) receptor dynamics in estrogen primed normal human cervix following P injection

Progesterone (P) receptor levels were measured in the cytosol and in the 0.4 M KCl nuclear extract in human cervical tissues with [3H]-R5020 as a ligand and the results compared with those obtained in the myometrium and endometrium of the same uteri. Tissue samples were obtained from 28 women, grouped as follows: group A, 12 premenopausal controls; group B, 7 perimenopausal women who received estrogen 7 to 11 days before operation; and group C, 9 perimenopausal and postmenopausal women who received estrogen as in group B plus P injection 1 to 3 hours before operation. Estrogen administration resulted in a significant rise in total P receptor levels in the cervix, compared with the endometrium and myometrium. P injection after estrogen priming resulted in down-regulation of the P receptor in the cervix to undetectable levels, whereas in the endometrium and myometrium it resulted only in redistribution of the P receptor, with higher nuclear levels and lower cytosol levels. These results indicate the possibility of a different mechanism of regulation of the P receptor in the human cervix, compared with that in the endometrium and myometrium.

Effects of dydrogesterone on the oestrogenized postmenopausal endometrium

Postmenopausal women receiving conjugated oestrogens 1.25 mg daily continuously were also given dydrogesterone either 5, 10 or 20 mg daily for the first 12 days of each calendar month. Endometrial tissue obtained on the sixth day of combined therapy in the third or subsequent treatment cycle was subjected to histological, ultrastructural and biochemical assessments. Dydrogesterone provoked secretory histological and ultrastructural changes within the endometrium in a dose-dependent manner. A daily dose of 5 mg produced sub-optimal responses but 10 and 20 mg daily produced effects similar to those observed in the secretory phase of the ovulatory cycle. Dydrogesterone 10 mg and 20 mg daily reduced epithelial DNA synthesis and nuclear oestradiol receptor levels to values within the secretory phase range. A dose-response relation was seen in the induction of oestradiol-17 beta and isocitrate dehydrogenase activities; hyperphysiological values were observed with 20 mg of dydrogesterone daily. This study has demonstrated that dydrogesterone exerts potent anti-oestrogenic and progestational effects on the human endometrium which are dose-related. The 10 and 20 mg doses induced responses equal to or greater than those observed in the secretory phase of the ovulatory cycle and both dosages can be recommended for use in combination with exogenous oestrogens in postmenopausal women: and they may also have a role in the management of anovulatory dysfunctional uterine bleeding.

Dose dependent effects of oral progesterone on the oestrogenised postmenopausal endometrium

Oral progesterone 100, 200, or 300 mg daily was given for the first 10 days of each calendar month to postmenopausal women also receiving conjugated oestrogens 1.25 mg daily continuously. Endometrial biopsy specimens were taken on the sixth day of the third or subsequent cycle of combined treatment for histological, ultrastructural, and biochemical evaluation. Secretory histological changes were induced within the endometrium in a dose dependent manner, as were progesterone sensitive ultrastructural features such as nucleolar channel systems, giant mitochondria, and subnuclear accumulations of glycogen. Dose response relations were also observed for suppression of DNA synthesis and nuclear oestrogen receptor, and for induction of the activities of oestradiol and isocitric dehydrogenases. Progesterone administered by mouth clearly provokes an end organ response within the endometrium. Suboptimal effects were observed with the lower doses but progesterone 300 mg daily achieved responses approaching and within the physiological range. This dose may therefore be effective as an alternative to synthetic progestogens for therapeutic purposes.