The effect of elevated ovarian hormones on periodontal health: oral contraceptives and pregnancy

The most common oral manifestation of elevated levels of ovarian hormones, as seen in pregnancy or oral contraceptive usage, is an increase in gingival inflammation with an accompanying increase in gingival exudate. This gingivitis can be avoided or at least minimized by establishing low plaque levels at the beginning of pregnancy or the beginning of oral contraceptive therapy. It would appear that bacteria are not solely responsible for the gingivitis seen during these times, nor are the ovarian hormones solely responsible for the condition. Data from numerous studies suggest that the ovarian hormones alter the microenvironment of the oral bacteria so as to promote their growth and shifts in their populations. The present article reviews the current state of knowledge concerning the relationship of gingivitis to elevated levels of ovarian hormones, and describes the role that these hormones may play in the gingivitis associated with pregnancy or oral contraceptive usage.

Effects of hormone therapy on the endometrium

Hormone therapy induces a variety of histologic changes in the endometrium. Histologic patterns encountered in the most commonly used hormonal regimens are described. Oral contraceptives are associated with inactive, atrophic, or pseudosecretory glands and edematous stroma, decidual reaction without spiral arterioles, and stromal granulocytes. A high-potency progesterone may induce marked stromal and vascular hyperplasia and stromal myomatous nodules. Ovulation induction therapy accelerates the maturation of the stroma and is often associated with a discrepancy between the glands showing early secretory changes and an edematous, decidualized stroma. Hormone replacement therapy may stimulate endometrial proliferation if estrogens are used alone and produce endometrial hyperplasia and neoplasia. When estrogen and progesterone regimens are used, a wide range of histologic pattern may be found in various combinations: proliferative and secretory endometrium, glandular and adenomatous hyperplasia, stromal hyperplasia and decidual transformation, glandular metaplasia, atrophic endometrium, and any of the above with endometrial atrophy. Progesterone therapy for endometrial hyperplasia and neoplasia is followed by secretory changes of the endometrium, mostly subnuclear vacuoles, decidual reaction, and sometime squamoid "morules." Secretory changes seen after progesterone therapy in the endometrium do not rule out residual carcinoma. For hormone therapy for breast carcinoma, tamoxifen acts as an antiestrogen on the breast but often acts as an estrogen agonist on the endometrium; tamoxifen therapy may be associated with endometrial hyperplasia, polyps, adenomyosis, adenomatous hyperplasia, and adenocarcinoma.

Comparative bioavailability of orally and vaginally administered progesterone

OBJECTIVE

To study the pharmacokinetics of progesterone (P) in healthy premenopausal female volunteers to compare the bioavailability of orally or vaginally administered hormone.

DESIGN

Subjects were randomly allocated to receive either oral P or a vaginal pessary then crossed over to the alternate preparation 1 month later.

SETTING

The study was conducted in outpatient setting.

SUBJECTS

All subjects were healthy, normal female volunteers who underwent a physical and gynecological examination before the study. None were using oral contraceptives. Ten subjects (mean age 32.6 +/- 7.3 years) entered the study and all completed it.

INTERVENTIONS

Progesterone was administered as 200 mg of micronized hormone or as a pessary containing 400 mg.

MAIN OUTCOME MEASURE

Plasma levels of P were measured by radioimmunoassay to test the apriori hypothesis of similar bioavailability.

RESULTS

Peak plasma P concentrations attained within 4 hours after oral administration ranged from 8.5 to 70.6 ng/mL, whereas after vaginal administration the peak levels were attained within 8 hours and ranged from 4.4 to 181.1 ng/mL. Considerable interindividual variation was noted. Area under the plasma concentration-time curve for the two formulations was not significantly different (F = 1.09; P greater than 0.1; ANOVA).

CONCLUSIONS

The two formulations had similar bioavailability.

Intracellular calcium accumulation and responsiveness to progesterone in capacitating human spermatozoa

Progesterone induced a rapid, long-lasting, dose-dependent increase of intracellular free calcium concentration ([Ca2+]i) in human sperm capacitated overnight. This effect was not counteracted by the cytosolic progesterone receptor antagonist RU486 (1 mumol/L) nor by the GABA-A receptor antagonists bicuculline (10 mumol/L) and picrotoxin (50 mumol/L). Also, the rank order of potency of several progestative steroids on [Ca2+]i differed from that previously reported for uterine intracellular progesterone receptor or for P-GABA interaction in the central nervous system, indicating a different pathway for progesterone stimulation of human sperm. Modifications of basal and progesterone-stimulated [Ca2+]i during sperm capacitation were also studied. A progressive, parallel increase of basal and progesterone-stimulated [Ca2+]i in capacitating spermatozoa was found. In particular, progesterone-stimulated [Ca2+]i increased from a basal concentration of 147% +/- 17% at 10 minutes to 327% +/- 65% after 120 minutes of incubation in capacitating medium. This increase was well correlated with basal [Ca2+]i (r = 0.93). In contrast, basal and progesterone-stimulated [Ca2+]i concentrations were constantly low in spermatozoa incubated in noncapacitating medium. In capacitated spermatozoa, initial responsiveness to progesterone and basal [Ca2+]i was higher than in capacitating and noncapacitated samples, and remained constant throughout the duration of the experiment. The progressive, parallel increase of [Ca2+]i and response to progesterone observed during in vitro capacitation of human spermatozoa might be physiologically relevant in vivo during capacitation of sperm in the female genital tract.

Endogenous and exogenous endocrine factors

The relationship between breast cancer risk and age at menarche, age at first pregnancy, use of birth control pills, and use of postmenopausal replacement estrogens is reviewed.

Plasma glucose and insulin levels in women using a levonorgestrel-containing triphasic oral contraceptive for three months

Plasma glucose and insulin levels were measured for three hours after an oral glucose challenge in twenty-nine women before and after using a triphasic oral contraceptive containing ethinyl estradiol and levonorgestrel for three months. There were significant elevations in the glucose levels during the three-month tolerance test, while the insulin levels were unchanged. These data suggest that this OC can alter carbohydrate metabolism and that long-term studies are needed to assess the extent of this metabolic change.

Pharmaceutical effect of contraceptive pills on the skin

Described are the various effects of birth control methods on the skin-mainly those of the contraceptive pill. The equilibrium of healthy skins and mucosa might be affected by these chemicals or pharmaceutical agents, causing different manifestations. The skin and mucosa should be looked upon as integral parts of the human body and its functions even where localized symptoms arise.

Alternate delivery systems for contraceptive progestogens

Research continues toward developing an universally acceptable, safe, and effective contraceptive to inhibit the female reproductive process. Progestational systems, either alone or in combination with small amounts of estrogen, approach such an ideal. The pregnane and 19-nortestosterone progestins were examined in this review with regard to contraceptive mechanisms of action and major side effects, such as menstrual abnormalities, metabolic changes, neoplasia, and teratogenicity. These steroids provide highly effective and long-acting contraception, and bypass the oral route of administration, resulting in fewer gastrointestinal and systemic side effects. Data regarding the lack of a deleterious effect of contraceptive progestogens on fetal malformation or cancer of the breast and genital tract reinforce their safety. Further study and refinement are needed, however, to lower the incidence of menstrual abnormalities, hypertension, and detrimental lipid alterations prior to approval for general use.

Multicenter trial of a monophasic oral contraceptive containing ethinyl estradiol and desogestrel

A clinical trial was conducted at 47 centers in 11 countries to assess the efficacy and acceptability of a monophasic oral contraceptive containing 30 micrograms ethinyl estradiol and 150 micrograms desogestrel. 1,613 women took part for a total of 23,258 cycles. One pregnancy occurred in a cycle where two consecutive tablets had been forgotten. Cycle control was excellent, with reported decreases in the duration and amount of withdrawal bleeding during consecutive treatment cycles and a low incidence of irregular bleeding. Blood pressure was not affected during 2 years of use. The incidence of minor side effects was already low in the first treatment cycle and decreased further in the subsequent cycles. The combination (Marvelon) was shown to be a very reliable and acceptable oral contraceptive.

Metabolic effects of oral contraceptives

Combination oral contraceptives (OCs) are probably not an independent risk factor for cardiovascular disease but through their metabolic actions, may partly amplify the effects of known risk factors for cardiovascular disease. This review of the literature and our own data indicate that use of high-dose, progestogen-dominant OCs induces a potentially atherogenic lipoprotein profile (high low-density lipoprotein-cholesterol:high-density lipoprotein-cholesterol ratio), mostly attributable to the antiestrogenic action of the progestogen content of these OCs. In contrast, lower-dose combination OCs with reduced amounts of progestogens and slight estrogen dominance, either monophasic or multiphasic, produce strikingly fewer adverse effects on lipoproteins. Moreover, use of low-dose, as opposed to high-dose, OCs results in almost unchanged glucose tolerance, marginally increased or unchanged insulin and glucagon responses to glucose, and probably unchanged levels and activity of peripheral insulin receptors. Further in-depth studies of low-dose OC formulations are mandatory to ascertain reduced metabolic risk of these OCs.

Oral contraceptive steroid induced platelet coagulant hyperactivity: dissociation of in vivo and in vitro effects

The use of oral contraceptives (OC) has been associated with an increased risk of thromboembolic events in a subset of women. Factors predisposing to this problem are still not clearly defined although an increased platelet coagulant activity (CA) has been reported. This study was designed to evaluate the CA of platelets from asymptomatic current OC users compared with control subjects. The asymptomatic OC users were found to have evidence of hypercoagulability in the form of increased availability of platelet CA. These findings were present in both collagen stimulated and unstimulated platelets. In order to understand the mechanism we examined the in vitro effects of estradiol and/or progesterone on platelets. Platelets from normal males were incubated for one hour with estrogen and/or progesterone. There was no significant difference in CA of hormone treated platelets compared with control platelets from the same donor. CA was analyzed in platelets exposed to epinephrine, adenosine diphosphate, and collagen in the platelet aggregometer. Although a dose dependent effect was observed on CA of platelets exposed to the range of aggregating agents, the results show no significant difference between CA of the hormone treated and control platelets (p greater than 0.05). Likewise, platelet aggregation and release of nucleotide were not different between hormone treated and control platelets. Thus a direct effect of the hormones on platelets is an unlikely mechanism causing the increased CA seen in OC users.

Coagulation effects of oral contraception

In Europe and North America, estrogen/progestogen oral contraception has been associated with an increase in venous thromboembolism, myocardial infarction, and stroke. These hazards are found mainly in smokers and in women over the age of 35. Venous thromboembolism appears to correlate with the estrogen dosage, and the arterial complications with both the estrogen and progestogen components. Blood coagulation and vascular thrombosis are intimately related. Estrogen/progestogen oral contraception affects blood clotting by increasing plasma fibrinogen and the activity of coagulation factors, especially factors VII and X; antithrombin III, the inhibitor of coagulation, is usually decreased. Platelet activity is also enhanced with acceleration of aggregation. These changes create a state of hypercoagulability that, to a large extent, appears to be counterbalanced by increased fibrinolytic activity. Studies of the oral contraceptives in current use show that the coagulation effects depend on the dosage of estrogen and the type of progestogen used in combination. Current research is aimed at finding the estrogen/progestogen formulations that induce the least changes in the coagulation system and other physiologic processes. In this respect, the new low-dose formulations are a major step forward and should reduce the risk of vascular thrombotic complications.

Progestogen potency in oral contraceptive pills

The most important target organs for combined oral contraceptive preparations are the anterior pituitary gland and the uterus. The long-term unopposed administration of estrogen produces endometrial hyperplasia and amenorrhea, which are unacceptable to most women and their medical advisors. Cyclic administration of progestogens in combination with the estrogen, however, produces predictable endometrial shedding and achieves a regular and acceptable bleeding pattern in most women. This was the main reason that the "delay of menses" test was adopted as the earliest clinical means of comparing the relative potencies of progestogens that were administered orally. Recently attempts have been made to compare the potency of progestogens on the other organ systems by the extrapolation of data derived from studies on the endometrium. This is inappropriate, inasmuch as the effects of progestogens and estrogens independently and in combination differ greatly depending on the target organ. In this article, the literature on this controversial subject is reviewed.

Contraceptive progestins and gonadotropin secretion in vitro

In an in vitro bioassay using rat pituitary cell cultures the effect of contraceptive progestins was tested on basal and gonadotropin-releasing hormone (GnRH)-induced luteinizing hormone (LH) and follicle-stimulating hormone (FSH) secretion in vitro. Progestins diminished gonadotropin release in pituitary cells stimulated with GnRH, but did not alter basal values. This inhibitory effect was dose dependent in a range of 10(-10)-10(-5) M tested and the inhibitory action of most of the progestins examined was more potent than that of progesterone. The maximal reduction of LH and FSH values was by 60% of GnRH-induced control levels. Progestins also caused a shift in sensitivity of cells to GnRh (10(-12)-10(-6) M). When time dependence was investigated, some progestins potentiated GnRH effect on gonadotropins in pituitary cell cultures pre-incubated for a short time (4 h) with steroids. More prolonged pre-incubations from 23 to 71 h resulted in a progressive suppression of LH and FSH response to GnRH (10(-7) M). In order to examine intracellular effects, cells were pretreated with progestins and inositol phosphate metabolism was investigated. The data obtained in pituitary cells give evidence that polyphosphoinositide breakdown is potentially an early step in the action of GnRH on gonadotropin secretion by providing diacylglycerol and inositol phosphates. Addition of gonadotropin-releasing hormone to myo-2[3H]inositol-prelabeled rat pituitary cells in primary culture evoked a dose-dependent increase of the accumulation of [3H]inositol phosphates with a rise of inositol triphosphate, inositol diphosphate and inositol monophosphate within 1 min. Using one contraceptive progestin, gestoden, inositol phosphate production was inhibited by 80% compared to controls of GnRH-treated cells without the addition of steroids. The data obtained in this study suggest that this in vitro bioassay using rat pituitary cells is a useful tool in testing progestational compounds regarding their potency on gonadotropin release. In addition, these results show that one possible site of interference of progestins with GnRH-induced gonadotropin secretion may involve polyphosphoinositide breakdown.

The antiprogestins: a recent advance in fertility regulation

RU 468 (mifepristone) is the first antiprogestin available for clinical purposes. Its pharmacological properties are presented. It possesses antiprogestin and antiglucocorticoid activities. It is now in phase II-III clinical studies as a fertility control agent. The drug appears useful per se in four circumstances: (1) for early pregnancy (amenorrhea of less than 5 weeks' duration). Complete interruption is obtained in approximately 90% of women with a single dose of 600 mg. For this stage of pregnancy, RU 486 appears to be an interesting alternative to vacuum aspiration; (2) for late occasional luteal contraception when given as a single dose on the date of the expected period in women at risk of pregnancy; (3) for dead fetus expulsion in the 2nd or 3rd trimester of pregnancy, and (4) for cervical ripening before obstetrical procedures in pregnant women, such as D and C or vacuum aspiration. The antiglucocorticoid activity of the molecule can be demonstrated in humans by a rise in plasma cortisol, ACTH and LPH after RU 486 intake, and by blockade of some peripheral effects of cortisol. Results obtained in more than 1000 women undergoing short-term treatment with RU 486 (600 or 800 mg once) clearly indicate that the antiglucocorticoid activity of the molecule has no clinical relevance at the doses used for fertility control purposes. In conclusion, RU 486 appears to be a promising new tool for fertility control, but large-scale trials are necessary to confirm its safety and to define its optimal mode of utilization for each indication.

Neurology of sex steroids and oral contraceptives

Under normal circumstances, sex steroids interact with diverse neural substrates to modulate a host of activities essential to the preservation of the individual and the species. In addition, sex hormones play an important role in various human neurologic conditions including strokes, migraine, certain movement disorders and peripheral neuropathies, and possibly even the behavior of CNS neoplasms.

Progesterone-induced erythema multiforme

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Pharmacodynamic studies on desogestrel administered alone and in combination with ethinylestradiol

Most progestogens in oral contraceptives are testosterone derivatives and have androgenic side effects such as weight increase, acne and hirsutism. They pose a problem to many women just like the clinical picture of the polycystic ovary syndrome (PCO) with obesity, hirsutism, acne and amenorrhea. The aim of this study was to evaluate androgenicity of the most used progestogens with special reference to desogestrel which is a new progestogen. Radioimmunoassay was used for hormone determination while serum proteins were determined with electroimmunoassay or in some studies for sex hormone binding globulin (SHBG) with capacity assays. Serum lipids and lipoproteins were determined in serum and after ultracentrifugation in HDL, LDL and VLDL fractions. In a comparative study on levonorgestrel/ethinylestradiol (EE) (n = 10) versus desogestrel/ethinylestradiol (n = 10) the latter combination gave increases in SHBG capacity while the former did not. Similar increases in estrogen-sensitive proteins cortisol binding globulin (CBG) and ceruloplasmin indicated that the estrogenicity and "antiestrogenicity" was the same for the two combinations whereas the androgenicity of levonorgestrel was greater giving a reduction in the EE-induced increase in SHBG (SHBG is increased by estrogens and suppressed by androgens). When giving desogestrel 0.125-0.500 mg and lynestrenol 5 mg alone in daily doses to a group of regularly menstruating women (n = 8) strong suppression of SHBG was achieved while ceruloplasmin, CBG and thyroxine binding globulin (TBG) did not change. TBG is decreased and prealbumin increased by androgenic/anabolic activity but only a moderate increase in prealbumin was found during lynestrenol treatment. The changes in SHBG are probably the result of a dose-dependent receptor interaction related to 17 alpha-alkylation in 19-norsteroids. Twenty women with PCO were treated for 8 months with 0.150 mg desogestrel/0.030 mg EE. Evaluation was done before treatment and after 3 and 8 "pill" cycles regarding androgens, estradiol, SHBG, hirsutism and body weight. Spontaneous menstrual cycles were assessed after treatment. Serum lipids and lipoproteins were studied before treatment and at the end of the third "cycle". In PCO the suppression of increased total and free testosterone levels (in comparison to 22 healthy women) was evident during treatment, concordant with increases in SHBG capacity. Hirsutism was suppressed and body weight was reduced in obese women.(ABSTRACT TRUNCATED AT 400 WORDS)

Increased risk for cancer of the breast due to previous medication

Fifteen patients presenting one or more risk factors for cancer of the breast, who also received medication with prolactin-stimulating effects, were selected. The medication was by hormone derivatives or by non-hormone drugs used for processes other than oncologic . In all cases the medication was for long periods, three or more years, with the exception of one case, where the correlation with the unfavourable evolution of the cancer process was more evident. In patients presenting the classic risk factors for cancer of the breast, it is recommended to avoid the prescription of drugs having a prolactin-stimulating effect. The association of both circumstances (risk factors and prolactin-stimulating medication) is considered as an increased risk for cancer of the breast.

Role of estrogens and progesterone in the etiology and prevention of endometrial cancer: review

Our present knowledge of the role of sex steroids in the development as well as the prevention of endometrial cancer is reviewed. Factors which increase the exposure of the uterus to unopposed estrogens, either exogenous or endogenous, are associated with increased risk of endometrial adenocarcinoma. However, there is increasing evidence that progestogens can reverse endometrial hyperplasia and protect against the development of endometrial cancer. The mechanisms to explain the antiestrogenic effects of progestogens include changes in enzyme activity and steroid receptors in endometrial tissue. Postmenopausal women treated with combined estrogen and progestogen have the lowest incidence of endometrial carcinoma. Oral contraceptives containing both estrogen and progestogen in each tablet are protective against adenocarcinoma of the endometrium, while the sequential oral contraceptive pills afforded less protection. The risks and benefits of these hormone therapies are discussed in relation to the etiology and prevention of endometrial cancer.

Effect of estrogen/progestin potency on lipid/lipoprotein cholesterol

We studied 374 women taking oral contraceptives, 284 women taking estrogen preparations after menopause, and 1086 women taking no hormones, to determine the relation of plasma lipids and lipoprotein cholesterol concentrations to various types of estrogen/progestin formulations. Premenopausal women, using oral contraceptives containing a relatively low dose of estrogen combined with a medium or high dose of progestin (Norlestrin, Ovral, or Demulen) had a 24 per cent higher median concentration of low-density-lipoprotein cholesterol than did those not using hormones (P less than 0.05). Women using oral contraceptives that are high in estrogen and low in progestin (Enovid or Oracon) had significantly higher concentrations of high-density-lipoprotein cholesterol than did nonusers; those using Ovral, a low-estrogen and high-progestin formulation, had significantly lower levels of high-density-lipoprotein cholesterol. In postmenopausal women the use of estrogen was associated with concentrations of low-density-lipoprotein cholesterol that were 11 to 19 per cent below the levels in postmenopausal women who did not use hormones. The effects of estrogen-progestin balance on low-density and high-density lipoproteins may underlie the increased incidence of stroke and myocardial infarction in women of childbearing age who take oral contraceptives.

Studies on cell-mediated immunity in women using different fertility regulating methods

Cell-mediated immunity (CMI) was assessed in women using fertility regulating methods for 1-5 months, 6-11 months or 12-18 months. The CMI as assessed by phytohaemagglutin in (PHA)-induced lymphocyte transformation of treated groups were compared with that of normal subjects who were not using any contraceptive methods and women on conventional methods of contraception. The data obtained indicates that there is no significant alteration of CMI in women fitted with IUCD or women on estrogen progestogen combination. However, a significant suppression of CMI is observed in women in progestogen pills for 12-18 months. The short term therapy did not affect the CMI. In a prospective study it was found that the CMI in women before and after the use of combination therapy for 1-5 and 6-11 months revealed no change. Estradiol and progesterone at concentration on 1 microgram/ml in culture medium suppressed PHA-induced lymphocyte transformation.

Pituitary, ovarian and endometrial effects of progesterone released prematurely during the proliferative phase

The pituitary, ovarian and endometrial effects of premature exposure to progesterone during the proliferative phase were investigated in 18 normally menstruating women. Daily blood samples were drawn during a control cycle and an endometrial biopsy was obtained on cycle day 6 (in 9 subjects) and on cycle day 11 (in 9 subjects), respectively. Daily blood samples were drawn again throughout a treatment cycle, in which a vaginal delivery system releasing progesterone at a constant rate of 1.4 mg/24 h was inserted and left in situ for 96 hours during cycle days 2-6 (9 subjects) and cycle days 7-11 (9 subjects), respectively. On the 6th and 11th cycle day, respectively, the devices were removed and another biopsy specimen was obtained. In all blood samples the levels of immunoreactive lutropin (LH), estradiol (E2), 17-hydroxyprogesterone (17-HO-P), progesterone (P) and 20 alpha-dihydroprogesterone (20 alpha-HO-P) were estimated by radioimmunoassay. Insertion of the devices resulted in a rapid, approximately six-fold increase (from 0.5 to 3.0 nmol/l) in P levels and an approximately three-fold (from 0.5-0.6 to 1.5-2.0 nmol/l) increase in 20 alpha-HO-P levels. A high degree of correlation was found between P and 20 alpha-HO-P levels. No major changes were observed in the profiles and levels of the other hormonal indices studied. However, premature exposure to small amounts of P during cycle days 2-6 resulted in a significant decrease in the ratio of the E2 to LH peaks and exposure during cycle days 7-11 gave rise to a significant increase in the ratio of the length of follicular to luteal phases. Progesterone released during the early proliferative phase (days 2-6) exerted little, if any, effect on the appearance of the endometrium. However, the same dose of P released during the late proliferative phase (days 7-11) significantly diminished the number of glandular mitoses, the height of the glandular epithelium, reduced pseudostratification and the number of plasmolemmal vesicles, but did not induce any subnuclear vacuolation, predecidual reaction or leucocytic infiltration. It is suggested that systematic studies involving the exposure to progestogens in normally menstruating women during cycle days 7 to 11 will provide a reliable and practical method for the comparative assessment of the potency profile of individual progestogens in women.

[Changes in serum beta-thromboglobulin levels during oral contraception, cardiac valve disease and pulmonary embolism (author's transl)]

beta-thromboglobulin (beta TG), a platelet-specific protein, was measured in the plasma of 53 healthy subjects (20 men and 33 women), 53 women using estrogen-progestogen contraceptives, 31 patients with cardiac valve disease (including 19 with prosthesis) and 71 patients about to undergo scintigraphy for suspected pulmonary embolism. Compared with levels in healthy subjects, beta TG levels were significantly increased in oral contraceptive users and in cardiac patients with or without prosthesis. High beta TG levels were also found in 20 out of 28 patients with pulmonary embolism confirmed by scintigraphy, but also in some of the .9 lung patients with chronic bronchopulmonary disease. Cardiac patients treated with heparin had higher beta TG levels than non heparin-treated patients, which raises queries about a possible influence of heparin on this particular blood protein.

Mammary tumors and serum hormones in the bitch treated with medroxyprogesterone acetate or progesterone for four years

After 4 years of a long-term contraceptive steroid safety study, the incidence and the histologic types of mammary dysplasia produced are shown to be similar in beagles treated with medroxyprogesterone acetate (medroxyprogesterone) or progesterone. Serum insulin, thyroid-stimulating hormone (TSH), triiodothyronine, growth hormone, prolactin, 17 beta-estradiol, progesterone, and cortisol were determined by radioimmunoassay on samples collected after 45 months of treatment. Serum growth hormone and insulin concentrations were elevated in a dose-related manner in both treatment groups. Levels of triiodothyronine, cortisol, and 17 beta-estradiol (medroxyprogesterone only) were lowered. TSH and prolactin concentrations were not changed. Pituitary-gonadal hormone interaction in the pathogenesis of mammary neoplasia of the dog is discussed. Prolonged treatment of beagles with doses of progesterone or medroxyprogesterone 1 to 25 times the human contraceptive dose or luteal phase (dog) levels, respectively, results in a dose-related incidence of mammary nodules.

Interference of gestagens and androgens with rat uterine oestrogen receptors

The inhibitory effect of some gestagens and calusterone on the binding of oestradiol-17beta to its specific uterine receptors has been investigated in intact rats. Progesterone, medrogestone, clogestone, medroxyprogesterone acetate and calusterone reduce the specific oestradiol-receptor interaction in vitro; this effect is dose-dependent and does not differ significantly from one drug to the other. A more relevant decrease in the amount of oestradiol-17beta bound to specific receptors has been observed with calusterone. Progesterone, clogestone, medrogestone, medroxyprogesterone acetate and calusterone given orally induce a marked decrease (between 30 and 70% depending on the dose) in the binding capacity of oestradiol-17beta to specific uterine receptors in vivo. Results from a Scatchard plot analysis suggest that the interference with the binding of oestradiol-17beta caused by both progestogens and calusterone is due to a non-competitive interaction.

Effects of progesterone on some enzymes of fat and carbohydrate metabolism in rat liver

The known effect of progesterone on carbohydrate metabolism prompted a study of some of the hepatic "lipogenic" and "gluconeogenic" enzymes in rats treated with progesterone. Several enzymes providing lipid precursors (phosphofructokinase, malic enzyme, glucose-6-phosphate dehydrogenase, and citrate cleavage enzyme) showed increased specific activity. These changes may represent insulin effects. Specific activity of phosphoenolpyruvate carboxykinase, usually associated with control of gluconeogenesis, was also increased. The latter is compatible with increased capability for glycogenesis, which is recognized as a progesterone effect.

Mechanism of oestrogen and progesterone effects on lipid and carbohydrate metabolism: alteration in the insulin: glucagon molar ratio and hepatic enzyme activity

As in women receiving oestrogens the administration of 17beta-oestradiol to ovariectomized female rats caused a rise in fasting plasma triglycerides and a fall in plasma glucose. Progesterone, on the other hand, had no significant effects. In the oestradiol treated rats, the portal vein basal insulin levels were slightly reduced. Oestradiol, however, had a marked suppressive effect on the alpha cells of the pancreas resulting in a greater reduction in basal glucagon and impaired glucagon response to alanine infusions. The relative insulin to glucagon (I/G) molar concentration ratio in portal vein blood was increased. Oestradiol also produced a dose dependent increase in the activity of the liver lipogenic enzymes, acetyl CoA carboxylase and fatty acid synthetase. On the other hand, the activity of the gluconeogenic rate limiting enzyme phosphoenol-pyruvate carboxykinase (PEPCK) was inhibited. The cross-over pattern of gluconeogenic intermediates confirmed inhibition of gluconeogenesis at this step, an effect which is similar to that induced by relative insulin 'excess'. Progesterone produced an increase in the portal vein insulin concentrations. Both the basal and the alanine-stimulated glucagon levels were also increased. The I/G molar ratio in portal vein blood of progesterone treated rats remained unaltered and the hepatic lipogenic and gluconeogenic enzyme activities were similar to control animals. These data suggest that insulin activity is increased relative to glucagon in the liver of oestradiol-treated rats due to the rise in portal vein I/G ratio. The changes in liver lipogenic and gluconeogenic enzymes and the alterations in fasting plasma triglycerides and glucose in response to oestrogens could be secondary to this effect.

The interaction of clomiphene, estradiol, and progesterone in the control of rat uterine glycogen metabolism

Uterine glycogen accumulation was studied in ovariectomized rats treated with all combinations of clomiphene citrate (0.25 mg/kg) estradiol (1.0 micron g) and progesterone (5.0 mg). The rats were given three consecutive daily dosages and killed 24 hours after the final dosage. Based on biochemical data, either estradiol or clomiphene increased uterine glycogen concentration and total glycogen, but progesterone did not. Progesterone significantly suppressed both the estradiol and clomiphene-induced glycogen increases. Based on the histochemical results, progesterone also suppressed the estradiol and clomiphene-induced glycogen responses, but the tissue affected differed. Clomiphene markedly increased luminal epithelial glycogen whereas estradiol induced primarily myometrial glycogenesis. Progesterone completely suppressed the clomiphene-induced epithelial effect and partially suppressed the estradiol-induced myometrial effect. Clomiphene also suppressed the estradiol-induced myometrial response. The results indicate that progesterone does have a significant interaction with clomiphene in the control of uterine morphology and biochemistry. The results also stress the importance of correlated histochemical and biochemical studies in the study of clomiphene-induced uterine glycognesis.

Effects of exogenous progesterone and oestradiol on prostaglandin F and 13,14-dihydro-15-oxo prostaglandin F2alpha concentrations in uteri and plasma of ovariectomized ewes

The control of prostaglandin (PG) production by steroid hormones has been investigated in non-pregnant bilaterally ovariectomized sheep, prepared with indwelling utero-ovarian venous catheters and treated with physiological amounts of oestradiol and progesterone. Oestradiol treatment alone (2 × 15 μg/day for 9 days) had no effect on the prostaglandin F (PGF) concentration in uterine caruncles or intercaruncular tissue, on the release of PGF or of 13,14-dihydro-15-oxo PGF (PGFM) from these tissues during incubation in vitro, or on the concentrations of PGF in the utero-ovarian vein or PGFM in the jugular vein. However, oestradiol did accumulate in the uterine tissues. Progesterone treatment alone (2 × 10 mg/day for 9 days) provoked a significant increase in the concentration of PGF in the caruncles, a significant increase in the release of PGF from the caruncles during incubation with arachidonic acid and increased mean concentrations of PGFM in the jugular vein. When oestradiol was superimposed on a progesterone-primed system, there was a further marked increase in the PGF content of the caruncles, release of PGF into the utero-ovarian vein, and increased concentrations of PGFM in the jugular vein. The caruncles always contained more PGF than the intercaruncular area, and released more PGF and PGFM during incubation in vitro. In the progesterone+oestradiol group, there was good correlation between the PGF concentrations in simultaneous samples from the right and left utero-ovarian veins, and for all groups there was a high correlation between utero-ovarian PGF and peripheral PGFM concentrations. The caruncular epithelium of the progesterone-treated animals contained more lipid droplets than those of the other groups.

These data are consistent with a requirement for progesterone in activating 'prostaglandin synthetase' activity, and promoting PGF production, largely from the caruncles. After progesterone priming, the synthesis of PGF by the caruncles and PG release into the vascular system was increased further by oestradiol treatment, whereas oestradiol alone was without effect.

Progestagen effects on elicitation of aggressive behaviour in male mice

Effects of progesterone on production of androgen-dependent aggression-eliciting pheromones were investigated. Two groups of anosmic (non-fighting) castrated mice treated with testosterone or with testosterone and progesterone, respectively, were attacked to the same degree by intact, isolated (fighting) mice while control mice (castrated only) were attacked less. The findings support the ideas that progesterone may inhibit androgen-induced aggression via a neural and not via a somatic mechanism.

Estrogen-induced sexual receptivity and localization of 3H-estradiol in brains of female mice: effects of 5 alpha-reduced androgens, progestins and cyproterone acetate

Sexual receptivity induced in ovariectomized CD-1 mice with chronic daily administration of estradiol benzoate (E2 B) was blocked by concurrent administration of the 5 alpha-reduced androgen, dihydrotestosterone (DHT). Receptivity was restored in these females with progesterone-, but not with dihydroprogesterone-priming 6 hr prior to testing. Delaying the DHT injections until 12 hr after the E2 B injections greatly reduced its inhibitory properties. Receptivity in E2 B-primed females was also blocked by concurrent treatment with cyproterone acetate and 3 alpha-, but not 3 beta-adrostanediol. Pretreatment with DHT, or 3 alpha- or 3 beta-androstanediol failed to consistently affects 3H-estradiol accumulation in crude nuclear and supernatant fractions from brain and pituitary.

The effect of intrauterine progesterone treatment on the endometrial prostaglandin F content in the rabbit

The effect on rabbit endometrial prostaglandin F caused by progesterone delivered directly to the uterus was investigated. Four groups of animals were used in the experiment: (1) no treatment (control); (2) an empty Silastic capsule (as an intrauterine device [IUD]) was inserted in one horn and the other horn was sham-operated; (3) a Silastic capsule releasing 150 microng of progesterone/day was placed in one horn and the other horn was sham-operated; (4) a Silastic capsule releasing progesterone was placed in one horn and the opposite horn received an empty Silastic capsule. In group 1, which received no treatment, no difference was noted. In group 2, the prostaglandin content of the horn containing an empty IUD was significantly higher than that of the sham-operated horn. In group 3, the same significant difference was noted between the prostaglandin content of the IUD-containing, progesterone-treated horn and the sham-operated horn. In group 4, no significant difference was observed between the horn containing an inert IUD and that containing a progesterone-releasing device. The addition of progesterone to an IUD does not significantly affect the elevated prostaglandin content of the endometrium caused by an inert IUD.