Micronized progesterone: clinical indications and comparison with current treatments

OBJECTIVE

To integrate and evaluate the pharmacokinetic, endocrine, and clinical effects of micronized progesterone formulations.

DESIGN

Published articles concerning the pharmacokinetics of orally administered progesterone and the potential clinical uses of oral micronized progesterone were reviewed. Results concerning their use for secondary amenorrhea, premenopausal bleeding disorders, luteal phase dysfunction, termination of premature labor, hormone replacement therapy, and premenopausal syndrome are summarized. Critical issues to be resolved through ongoing preclinical and clinical research are highlighted.

RESULT(S)

Because of the enhanced bioavailability of oral micronized progesterone, the compound may be useful for a variety of therapeutic indications. Oral micronized progesterone is available in France, and a formulation recently has been approved in the United States for the treatment of secondary amenorrhea and postmenopausal hormone replacement therapy. A large body of evidence, including the Postmenopausal Estrogen/Progestin Interventions study, suggests that the use of a combination of estrogen and oral micronized progesterone is optimal for long-term hormone replacement therapy. There also are data indicating that oral micronized progesterone could be of potential use for the treatment of premenopausal bleeding disorders, luteal phase disorders, and premature labor.

CONCLUSION(S)

Oral micronized progesterone has widespread clinical potential, particularly for the treatment of secondary amenorrhea and dysfunctional premenopausal bleeding, and as a component of postmenopausal hormone replacement therapy.

Modulation of androgen metabolism by estradiol-17beta and progesterone, alone and in combination, in human gingival fibroblasts in culture

BACKGROUND

Androgens, particularly 5alpha-dihydrotestosterone (DHT), have anabolic effects on connective tissues and bone with implications on periodontal healing. This can be enhanced by estradiol-17beta (E-17beta), in synergy with androgen action. The effects of progesterone (P) contribute to plaque-induced inflammatory changes. The aim of this investigation was to study the modulation of androgen metabolism by E-17beta and P, alone and in combination.

METHODS

Human gingival fibroblasts were established in monolayer culture and duplicate incubations were performed in Eagle's MEM for 24 hours with either 14C-testosterone (14C-T) or 14C-4-androstenedione (14C-4-A) as substrate and serial concentrations of E-17beta, P and E-17beta + P. The medium was solvent extracted for steroid metabolites, analyzed, and quantified using a radioisotope scanner. The androgen substrates were converted mainly to DHT and 4-androstenedione/testosterone from 14C-T and 14C-4-A respectively.

RESULTS

At concentrations of 0.1 and 0.5 microg/ml, E-17beta stimulated DHT synthesis from 14C-T by 18% and 12%, respectively, decreasing to control values at 0.1 microg/ml. While the effect of similar concentrations of P on the same substrates was inhibitory by 18, 70, and 82% (n = 4; P <0.01). E-17beta + P showed a 12% increase in DHT synthesis over controls at 0.1 microg/ml, similar to that of E-17beta alone, despite the inhibitory effects of P (n = 4; P <0.01) with 12% and 77% decreases at 0.5 and 1 microg/ml (n = 4; P <0.01). The inhibitory effect of P on DHT synthesis was less apparent when E-17beta was present in combination. The formation of 4-androstenedione from 14C-T was stimulated by E-17beta (12.5%), inhibited by P (50%) and showed an intermediate response with E + P (33% stimulation). At the concentrations used, E-17beta stimulated DHT synthesis from 14C-4-A by 3.6-, 3- and 2.6-fold. P also stimulated this conversion from the same substrate by 16%, 2-fold, and 1.6-fold increases, partly due to the low yields at baseline. The combination of E + P stimulated the synthesis of DHT from 14C-4-A by 4-fold at 0.1 and 0.5 microg/ml and a 2.3-fold increase at 1 microg/ml. The formation of T from 14C-4-A was stimulated by E-17beta (50%) and inhibited by P (40%), with 93% stimulation by E + P at 0.1 microg/ml.

CONCLUSIONS

The modulatory effects of estradiol-17beta and progesterone on androgen metabolism may influence disease presentation and the progress of healing responses in the inflamed periodontium.

A simple, inexpensive and effective artificial cycle with exogenous transdermal oestradiol and vaginal progesterone for the transfer of cryopreserved pronucleated human oocytes in women with normal cycles

Supernumerary pronucleated stage oocytes (PN) are usually cryopreserved. PN are transferred in spontaneous, stimulated or artificial cycles. In this study, an artificial cycle with a transdermal therapeutic system was used for oestradiol release (Estraderm TTS 100) in combination with a targeted drug delivery system for vaginal progesterone release (Crinone 8%). Patients started transdermal 17beta-oestradiol treatment on cycle day 1. Only one clinical monitoring was necessary on day 14 for confirmation of satisfactory endometrial development and exclusion of ovulation by transvaginal ultrasound and endocrine determinations (oestradiol, progesterone and luteinizing hormone). Embryo transfer was performed on the third day of progesterone treatment (day 17). The first 25 cycles were recently completed in a prospective study; no cycles were cancelled due to ovulation or unsatisfactory endometrial development. In comparison with the previous protocol of embryo transfer in stimulated cycles in our clinic which required extensive ultrasound and endocrine monitoring, the pregnancy rate in these oestrogen- and progesterone-supplemented cycles was nearly twice as high (34.8%). Two pregnancies were even achieved with zygotes after micro-injection of frozen-thawed late spermatids extracted from testicular tissue (cryo-TESE). In these cycles, the Estraderm TTS 100/Crinone 8% protocol seems to be superior to stimulation protocols and even to other protocols reported so far for artificial cycles with exogenous oestradiol and progesterone treatment.

Progesterone and transforming growth factor-beta coordinately regulate suppression of endometrial matrix metalloproteinases in a model of experimental endometriosis

Endometriosis is a benign, though aggressive, disease of the female reproductive tract that consists of endometrial stromal and epithelial cells growing at an extrauterine site. Although it is widely accepted that the majority of cases of endometriosis result from the ectopic implantation of refluxed menstrual tissue, the precise mechanisms by which this disease becomes established are not well understood. Matrix metalloproteinases (MMPs), enzymes which are important for extracellular matrix turnover, have recently been implicated in the development of endometriosis. MMPs appear to be overexpressed in endometriotic lesions, but expression levels decrease following successful medical therapy. Intriguingly, although transforming growth factor-beta (TGF-beta) mediates progesterone suppression of specific endometrial MMPs, this growth factor is overexpressed in women with endometriosis. In the current study, we used an established experimental model of endometriosis to explore MMP regulation by TGF-beta. Our findings indicate that blocking the action of TGF-beta opposes progesterone-mediated suppression of MMPs and blocks the ability of this steroid to prevent experimental endometriosis. However, we also show that the action of TGF-beta does not lead to a sustained suppression of MMPs as observed following progesterone treatment. Taken together, our data suggest that in the absence of a normal progesterone response, common in ectopic lesions of endometriosis, sensitivity to TGF-beta may be altered, resulting in a failure to regulate MMPs.

Lack of effect of short-term micronized progesterone on bone turnover in postmenopausal women

A number of studies suggest that progestogens have beneficial effects on bone in postmenopausal women, particularly in combination with estrogen, although these studies have used derivatives that may have estrogenic and androgenic properties in addition to effects mediated by progesterone receptors. Progesterone itself affects only progesterone and glucocorticoid receptors. However, until the development of micronized progesterone (MP), absorption of progesterone preparations was too low to be clinically useful. MP has similar protective effects on the uterus and fewer effects on the lipid profile than other preparations, but its effects on bone are unknown. We tested the hypothesis that MP would alter bone turnover, as measured by serum and urine biochemical markers, in postmenopausal women. Fourteen women aged 65 or over who were not on estrogen replacement received a 6-week course of daily MP (200 mg). Markers of bone turnover were measured in serum and urine collected at baseline, at 6 weeks on MP, and 6 weeks after termination of MP. We also measured total and high-density lipoprotein (HDL) cholesterol and progesterone levels during the study. Markers of bone resorption were urinary free deoxypyridinoline cross-linked N-telopeptides and C-telopeptides of type I collagen. Markers of bone formation were serum osteocalcin, bone alkaline phosphatase, and type I C-terminal and N-terminal procollagen peptides. Using repeated measures analysis of variance, markers of bone formation and resorption did not change with MP treatment in spite of an increase in progesterone levels in all women. We conclude that 6-week treatment with MP alone does not have an effect on bone turnover in postmenopausal women in spite of high physiological levels. These data suggest that effects on bone demonstrated using other progestogen preparations might be due to androgenic or estrogenic effects or that progesterone may not affect bone in estrogen-deficient women.

Follicular growth, estrus and pregnancy after fixed-time insemination in beef cows treated with intravaginal progesterone inserts and estradiol benzoate

An experiment was performed to compare the effects of 3 short-term treatments with progesterone and estradiol benzoate (EB) on follicular growth, synchrony of estrus and pregnancy rate after fixed-time insemination in lactating postpartum beef cows. In Treatment 1 (n = 46), each cow received a progesterone-containing intravaginal insert for 7 d with injection of EB (2 mg, i.m.) at the time of device insertion. In Treatment 2 (n = 46), the insert was used for only 5 d with injection of EB (2 mg, i.m.) at the time of insertion. Cows in Treatment 3 (n = 47) received an insert for 5 d with no EB at the time of insertion. Each cow in the 3 groups received PGF2 alpha (25 mg, i.m.) at the time of insert removal, followed by EB (1 mg, i.m.) 30 h later. The cows were then inseminated 28 to 30 h after treatment with EB (58 to 60 h after insert removal). Treatment with 2 mg EB terminated the growth of the largest ovarian follicle (> 5 mm in diameter) at device insertion in 16/16 and 14/15 cows in Treatments 1 and 2, respectively. Estrus was detected within an 8-h target period (48 to 56 h after insert removal) in 93, 87 and 81% of cows in Treatments 1, 2 and 3, respectively (P > 0.05). Pregnancy rates at 39 d post insemination were 60, 50 and 51% for Treatments 1, 2 and 3, respectively (P > 0.05). The pregnancy rates did not differ between cows that were anovulatory or those that had ovulated before the initiation of treatments (54%), or among cows that were 28 to 40, 41 to 60 or > 60 days post partum at insemination (43, 59 and 54%, respectively). Treatment with progesterone inserts for 5 or 7 d, PGF2 alpha at the time of insert removal and 1 mg EB 30 h later induced the high degree of synchrony of estrus and ovulation necessary for fixed-time insemination.

Association of oestrogen receptor gene polymorphisms with outcome of ovarian stimulation in patients undergoing IVF

Oestrogen plays an important role in follicular formation and oocyte maturation via its receptor (ER). Many studies have shown association of the ER gene polymorphisms with a variety of pathological conditions. In this study we have examined the relationship of a common PvuII and a rare BstUI polymorphism in the ER gene to the mean numbers of follicles and oocytes, their mean ratios, mean number of embryos, mean oestrogen concentrations, mean size of the follicles and pregnancy rates. Analyses were carried out in 200 local Chinese patients undergoing in-vitro fertilization (IVF) and embryo transfer in three consecutive cycles. The mean follicular number, oocyte number, embryo number, follicular size and pregnancy rate were significantly smaller in patients homozygous for PvuII polymorphism (P < 0.001). These results indicate that PvuII polymorphism may be associated with ovarian follicular development and subsequently with the pregnancy rate. This study supports the view that genetic variability in the ER gene may have a role in the quality of the ovarian follicles in stimulation, which may affect implantation. However BstUI polymorphism was not found in either the IVF or control groups, suggesting that it has no role in the local Chinese population.

A phase II/pharmacokinetic trial of high-dose progesterone in combination with paclitaxel

PURPOSE

The purpose of this study was to investigate the effect of high-dose progesterone, an inhibitor of P glycoprotein, on the pharmacokinetics and toxicity of paclitaxel.

PATIENTS AND METHODS

A total of 29 patients with various tumors were treated with single-agent paclitaxel (125 mg/m2 administered over 3 h once every 3 weeks) until progression of disease, at which point high-dose progesterone (3 g administered i.v. over 24 h) was added to the paclitaxel treatment program in 20 patients (13 women, 7 men). Pharmacokinetic studies of paclitaxel administered alone and with progesterone were performed in eight patients.

RESULTS

The pharmacokinetic parameters of paclitaxel were highly variable. High-dose progesterone increased the peak plasma levels (3.00 +/- 0.94 vs. 4.15 +/- 1.63 microM; P = 0.029; mean +/- SD) and the area under the curve (AUC; 14.3 +/- 4.75 vs. 17.3 +/- 5.59 microM x h; P = 0.006) of paclitaxel. The absolute neutrophil and platelet nadir counts did not differ significantly between the paclitaxel and the combined treatment cycles. Three of the 20 patients documented to have progressive disease on paclitaxel alone had partial responses when high-dose progesterone was added to the paclitaxel regimen.

CONCLUSION

Progesterone had a statistically significant impact on the pharmacokinetics of paclitaxel. The addition of high-dose progesterone to paclitaxel is feasible, but the small number of patients prevents conclusions being drawn about the clinical efficacy of combined progesterone and paclitaxel.

Effect of postmenopausal hormones on inflammation-sensitive proteins: the Postmenopausal Estrogen/Progestin Interventions (PEPI) Study

BACKGROUND

Observational studies in healthy women suggest postmenopausal hormone therapy reduces risk of coronary events. In contrast, in a recent clinical trial of women with coronary disease, a subgroup analysis demonstrated increased risk during the early months of therapy. Because higher levels of inflammation factors predict vascular disease outcomes, the effect of hormones on these factors is of interest.

METHODS AND RESULTS

Four inflammation-sensitive factors, C-reactive protein, soluble E-selectin, von Willebrand factor antigen, and coagulation factor VIIIc were measured at baseline, 12, and 36 months in 365 participants of the Postmenopausal Estrogen/Progestin Interventions (PEPI) Trial, a randomized, placebo-controlled trial of the effects of 4 hormone preparations on cardiovascular disease risk factors. Compared with placebo, all 4 active preparations resulted in a large sustained increase in the concentration of C-reactive protein and a decrease in soluble E-selectin (P=0.0001). There were no effects of treatment on concentrations of von Willebrand factor or factor VIIIc. There were no differences in effects among treatment arms. Relative to placebo, when combining active treatment arms, final concentrations of C-reactive protein were 85% higher whereas E-selectin was 18% lower compared with baseline.

CONCLUSIONS

Postmenopausal hormones rapidly increased the concentration of the inflammation factor C-reactive protein. Such an effect may be related to adverse early effects of estrogen therapy. In contrast, hormones reduced the concentration of soluble E-selectin, and this might be considered an anti-inflammatory effect. Because PEPI was not designed to assess clinical endpoints, studies of the impact of hormone-mediated changes in inflammation on risk of subsequent coronary events are needed.

Treating cattle with progesterone as well as a GnRH analogue affects oestrous cycle length and fertility

Initiating the chronic administration of progesterone to cattle during metoestrus will produce shortened oestrous cycles containing one or two wave-like sequences of ovarian follicle development. Conception rates are reduced to inseminations at the oestrus preceding these shortened cycles. In contrast, a single injection of the GnRH analogue, buserelin, around mid-dioestrus can lengthen the oestrous cycle by increasing the proportion of cycles with three waves of follicular development and may also increase conception rates. A series of trials was conducted to test the hypothesis that the adverse effects of progesterone on oestrous cycle length and conception rate could be prevented with a strategic injection of GnRH. In Trial 1, progesterone was administered per vaginum to heifers for 10 days from Day 2 or 3 (Oestrus = Day 0) and with (n = 42) or without (n = 46) an injection of a GnRH analogue (10 microg buserelin) on Day 12 or 13. Other heifers (n = 44) served as an untreated control group. The average inter-oestrous interval (IOI) for those heifers treated only with progesterone was 17.0 days and was less (p<0.05) than the average intervals for those also receiving GnRH (20.2 days) or in the control group (20.0 days). In Trial 2, 45 heifers were inseminated following a synchronised oestrus. Progesterone was administered as in Trial 1 to 22 of the heifers. Their conception rate was 45.4% and this was less (p<0.05) than the 73.9% obtained with their 23 untreated contemporaries. Trial 3 was completed using 530 cows in commercial dairyherds. The 259 cows receiving progesterone and GnRH (buserelin) after their first inseminations had a conception rate of 68.3% compared to 56.1% for their 271 untreated herdmates (p<0.05%). Heifer calves born to treated cows had heavier birthweights (33.4 vs. 31.1 kg; p<0.05), but birthweights of bull calves were unaffected (35.5 vs. 35.8 kg). Gestation lengths for cows conceiving to first inseminations were similar for treated and control groups (280.9 vs. 280.5 days). The results of these trials confirmed the hypothesis that a strategic injection of the GnRH analogue, buserelin, could prevent the reductions in oestrous cycle length and conception rate associated with the chronic metoestrous administration of progesterone.

Preparation of nanoparticles consisted of poly(L-lactide)-poly(ethylene glycol)-poly(L-lactide) and their evaluation in vitro

This study describes the preparation and the evaluation of biodegradable poly(L-lactide)-poly(ethylene glycol)-poly(L-lactide) copolymer (PLA-PEG-PLA) nanoparticles containing progesterone as a model drug. PLA and PLA-PEG-PLA copolymers, whose PEG content ranged from 5.2 to 25.8% (w/w), were polymerized in our laboratory. PEG with weight-average molecular weight (Mw) 6600 or 20 000 was introduced as a hydrophilic segment into a hydrophobic PLA homopolymer. A solvent evaporation method was used to prepare the nanoparticles. The drug trapping efficiencies were around 70% and the weight-averaged mean diameters of the nanoparticles were less than 335 nm. The amount of drug released increased as the PEG content and Mw of PLA-PEG-PLA copolymers increased and the total Mw of copolymers of nanoparticles decreased. The initial burst of drug release was reduced by removing the low Mw fraction from the polymer. During the release test, both the extent to which the copolymers were degraded and the size of the nanoparticles were increased slightly by increasing the content of PEG in the polymers. Drug release from the nanoparticles could potentially be controlled by changing the PEG content, PEG Mw and total Mw of the copolymer. The molecular weight distribution (Mw/Mn, Mn: number-average molecular weight) of copolymers was also an important factor for controlled release.

Facilitation of sexual behavior in French-Alpine goats treated with intravaginal progesterone-releasing devices and estradiol during the breeding and nonbreeding seasons

The effectiveness of administering progesterone (P4) using controlled intravaginal drug release (CIDR) devices on estradiol (E2)-induced sexual behaviors was examined in ovariectomized (ovx) French-Alpine goats during the fall and spring. Estradiol-induced attractivity and receptivity were facilitated during the spring when P4-filled CIDR devices were removed 24 or 48 h before injection of 30 microg of E2. During the fall, attractivity was also facilitated by CIDR removal 24 h prior to E2 injection, whereas E2-induced receptivity was unaffected by removal of the CIDR at this interval. Concentrations of P4 in circulation during the 3 d of treatment with a CIDR were similar to those during the late luteal phase of the estrous cycle in intact goats. Treatment with P4-filled CIDR for 3 d, followed by injection with 30 microg of E2 24 h after removal, was determined to be a useful model for inducing sexual behavior in a physiologically relevant manner, and it may also be an effective means for facilitating estrus detection due to the high frequency of display of sexual behavior during a predictable time period following steroid treatment.

Decline in lung function in lymphangioleiomyomatosis: relation to menopause and progesterone treatment

The progression of lymphangioleiomyomatosis, a rare lung disease in women, is thought to be influenced by hormonal factors. We studied the rate of decline in FEV(1) and carbon monoxide transfer factor (TL(CO)) in a national cohort of patients with lymphangioleiomyomatosis in the United Kingdom and its relation to two factors that might influence the disease, menopausal status and progesterone treatment. We used retrospective data from hospital notes, and of the 50 patients identified 43 had suitable lung function data spanning at least 3 mo. Mean (SD) annual decline in FEV(1) was 118 (142) ml for all patients, and these figures changed little when only data spanning at least 2 and 3 yr were analyzed. There was considerable variation in the rate of decline between subjects, however, and although it tended to be less among postmenopausal women and those receiving progesterone, patient numbers were smaller and the findings were not significant. There was a significant reduction in decline in TL(CO) in premenopausal patients receiving progesterone and in both FEV(1) and TL(CO) after starting progesterone in six patients who had data before and after starting treatment. This study documents the rapid decline in lung function in lymphangioleiomyomatosis, confirms the wide variation between patients, and provides some support for the suggestion that disease progression may be reduced by progesterone. The data provide a basis for designing prospective studies of treatment for lymphangioleiomyomatosis.

The progesterone blockade of the luteinizing hormone surge is overcome by RU486

Progesterone can prevent the oestrogen-induced and spontaneous preovulatory luteinizing hormone (LH) surges but the mechanisms underlying this effect remain poorly understood. Using a follicular phase ovariectomised (OVX) ewe model and by elevating progesterone in the presence of oestrogen to inhibit the LH surge, we investigated whether the progesterone receptor antagonist, RU486, could block the inhibitory effects of progesterone. Accordingly, intravaginal progesterone implants were inserted into OVX Ile-de-France ewes (n = 18), bearing 10 mm Silastic 17beta-oestradiol implants. Ten days later, the progesterone implants were removed, whereupon new implants were inserted immediately into 12 ewes: six of which were also injected with 100 mg RU486 dissolved in 10 mL vehicle (10% alcohol in peanut oil) and six received vehicle only. The remaining six ewes were injected with vehicle only. RU486 and vehicle injections were made again 12 and 24 h later. After the last injection, oestrogen concentrations were raised to peak follicular phase levels in all ewes by subcutaneous insertion of four 3-cm 17beta-oestradiol implants. Blood samples were collected every 2 h for 40 h starting 9 h after the insertion of the oestrogen implants. As expected, the six ewes treated only with oestradiol had a LH surge whereas no ewes given the implants in the presence of progesterone surged. RU486 completely blocked the inhibitory effect of progesterone. There were no differences in the time of LH surge onset, duration over which LH levels remained above their half-maximal concentration or magnitude of the LH surge between the two groups showing surges. Our study suggests strongly that the progesterone-mediated blockade of the ovine oestrogen-induced LH surge is not through allopregnanolone activation of the GABA(A) receptor. Rather, our study demonstrates that this effect is transduced by the classic nuclear progesterone receptor.

Antisteroidal compounds and steroid withdrawal down-regulate cadherin-11 mRNA and protein expression levels in human endometrial stromal cells undergoing decidualisation in vitro

The cellular mechanisms by which steroids and antisteroidal compounds modulate the function and/or integrity of the human endometrium remain poorly understood. We recently determined that the expression of the novel cadherin subtype, known as cadherin-11, is tightly regulated in endometrial stromal cells undergoing decidualisation in vivo and in vitro. To determine whether the actions of antisteroids on the endometrium are mediated, at least in part, by their ability to regulate the expression of this cell adhesion molecule, we examined the effects of the antiprogestin RU486 and the antiestrogen ICI 182,780 on cadherin-11 mRNA and protein expression levels in human endometrial stromal cells undergoing decidualisation in vitro. RU486 decreased the levels of the cadherin-11 mRNA transcript and protein species present in these cell cultures in a dose- and time-dependent manner. Similarly, ICI 182,780 was capable of reducing stromal cadherin-11 mRNA and protein expression levels in a dose-dependent manner, suggesting that the progesterone-mediated increase in cadherin-11 expression levels in human endometrial cells undergoing decidualisation in vitro is dependent on the presence of estrogens. Cadherin-11 expression levels also were reduced in endometrial stromal cell cultures subjected to progesterone withdrawal, an in vitro model for menstrual breakdown. These studies not only give us useful insight into the mechanism(s) by which progesterone regulates stromal cadherin-11 expression, but they strengthen our hypothesis that this cell adhesion molecule plays a central role in the remodeling processes that occur in the human endometrium in response to fluctuations in the levels of gonadal steroids.

Are lower doses of estrogen effective against osteoporosis?

Researchers have found that, when combined with vitamin D and calcium, very low doses of estrogen can be used in hormone replacement therapy for postmenopausal women, significantly reducing complications, minimizing breast cancer fears, and potentially making the bone-saving therapy more palatable to a higher percentage of your patients.

Luteal support with micronized progesterone following in-vitro fertilization using a down-regulation protocol with gonadotrophin-releasing hormone agonist: a comparative study between vaginal and oral administration

This study aimed to compare the efficacy of micronized progesterone administered as luteal support following ovulation induction for in-vitro fertilization (IVF)- embryo transfer in cycles using gonadotrophin-releasing hormone agonist, either orally (200 mgx4/day) or vaginally (100 mgx2/day) and to characterize the luteal phase hormonal profile during such treatments. A total of 64 high responder patients requiring intracytoplasmic sperm injection due to male factor infertility were prospectively randomized into two treatment groups. Patients treated orally or vaginally were comparable in age (31.9 +/- 6.1 versus 30.6 +/- 5.2; mean +/- SD), number of oocytes retrieved (17 +/- 8.2 versus 18 +/- 7.0), and number of embryos transferred (3.1 +/- 1.2 versus 2.7 +/- 0.9) per cycle. Following low dose vaginal treatment, a significantly higher implantation rate (30.7 versus 10.7%, P < 0.01), but similar clinical pregnancy rate (47.0 versus 33.3%) and ongoing pregnancy rate (41.1 versus 20.0%) was observed, compared with oral treatment. In conception cycles, luteal serum progesterone and oestrogen concentrations did not differ between the treatment groups. In non-conception cycles, late luteal progesterone concentrations were significantly lower following vaginal treatment. As low dose micronized progesterone administered vaginally is simple, easy and well tolerated, it could be recommended as the method of choice for luteal support, especially for high responder patients at risk for ovarian hyperstimulation syndrome.

Effects of acute administration of natural progesterone on peripheral vascular responsiveness in healthy postmenopausal women

Peripheral vascular responses to acute administration of natural progesterone were studied in 12 postmenopausal women (mean +/- SD age 50.3 +/- 4.8 years) with no evidence of cardiovascular disease. According to a randomized, double-blind protocol, all subjects were given natural progesterone as a vaginal cream, able to produce a rapid peak and decay of plasma hormone concentrations, or matched placebo, with crossover after a 1-week washout period. Forearm blood flow and peak flow after ischemic stress (ml/100 ml/min), local vascular resistance (mm Hg/ml/100 ml/min), venous volume (ml/100 ml), and venous compliance (ml/100 ml/mm Hg) were measured by strain-gauge venous occlusion plethysmography at baseline and after progesterone or placebo administration. Plasma norepinephrine concentrations were determined by high-performance liquid chromatography with electrochemical detection. Progesterone sharply decreased forearm blood flow (p <0.01) through an increase in local vascular resistance (p <0.01). Measures of venous function remained unchanged. Although the hormone increased circulating norepinephrine concentrations (p <0.05), there were no significant changes in mean arterial pressure or heart rate. Furthermore, progesterone reduced the local vasodilator capacity, shown by a decrease in forearm delta flow (difference between peak flow and basal flow, p <0.05). Compared with the well-known effect of estrogen, progesterone exerted an opposite action on peripheral vascular responsiveness. Peripheral circulatory changes may be attributed to a direct activity of progesterone on the arterial wall and may in part reflect a modulation of the hormone on peripheral sympathetic tone. Consideration must be given to the hypothesis that the addition of progestin may attenuate the beneficial effects of unopposed estrogen replacement therapy in postmenopausal women.

Percutaneous progesterone use and risk of breast cancer: results from a French cohort study of premenopausal women with benign breast disease

Percutaneous progesterone topically applied on the breast has been proposed and widely used in the relief of mastalgia and benign breast disease by numerous gynecologists and general practitioners. However, its chronic use has never been evaluated in relation to breast cancer risk. The association between percutaneous progesterone use and the risk of breast cancer was evaluated in a cohort study of 1150 premenopausal French women with benign breast disease diagnosed in two breast clinics between 1976 and 1979. The follow-up accumulated 12,462 person-years. Percutaneous progesterone had been prescribed to 58% of the women. There was no association between breast cancer risk and the use of percutaneous progesterone (RR = 0.8; 95% confidence interval 0.4-1.6). Although the combined treatment of oral progestogens with percutaneous progesterone significantly decreased the risk of breast cancer (RR = 0.5; 95% confidence interval 0.2-0.9) as compared with nonusers, there was no significant difference in the risk of breast cancer in percutaneous progesterone users versus nonusers among oral progestogen users. Taken together, these results suggest at least an absence of deleterious effects caused by percutaneous progesterone use in women with benign breast disease.

Progesterone microinjections into the pontine reticular formation modify sleep in male and female rats

It has been reported that progesterone (P4) induces changes in sleep, but the brain regions involved in these actions are unknown. We studied the effects of P4 microinjections into the pontine reticular formation (PRF) upon rat sleep. Intact adult male and ovariectomized female rats were unilaterally injected with P4 into the PRF and the sleep-waking cycle was recorded for 6 h. P4 (1.0 and 5.0 microg/0.2 microl) did not modify sleep, but at a higher dose (7.5 microg/0.2 microl) it produced a marked decrease in rapid eye movement sleep (REM) latency in both male (55%) and female (63%) rats. A non-significant increase in the number of REM episodes was observed after P4 administration. These findings suggest that P4 should participate in the mechanisms related to REM initiation in the rat through its effects in the PRF.

Effects of sex hormones on production of interleukin-1 by human peripheral monocytes

BACKGROUND

Interleukin-1 (IL-1) is a potent mediator of inflammation and is known to induce bone resorption. We studied the effects of sex hormones on the function of human monocytes and demonstrated that prostaglandin E2 (PGE2) production was enhanced by progesterone and estradiol. As PGE2 has been shown to suppress the production of IL-1 by monocytes, it was speculated that sex hormones also modify the production of IL-1 by regulating PGE2 production. Thus, the effects of sex hormones on the production of IL-1 from human peripheral monocytes and the influence of PGE2 were investigated.

METHODS

Mononuclear leukocytes were obtained from 22 healthy adults. Progesterone, 17-beta estradiol (estradiol), and testosterone were used as representative sex hormones. Monocytes were incubated at 37 degrees C in air with 5% CO2 for 24 hours in RPMI 1640 medium with sex hormones at the designated concentrations. LPS (Salmonella typhimurium) was used to stimulate the monocytes at a concentration of 10 microg/ml. The concentrations of IL-1alpha and IL-1beta in the medium were determined by enzyme-linked immunosorbent assay kits. The concentration of PGE2 was determined using a direct radio-immunoassay kit. Indomethacin was used to inhibit the synthesis of PGE2 and eliminate its effect on the production of IL-1.

RESULTS

Estradiol at concentrations of 0.04 ng/ml or more significantly reduced both IL-1alpha and IL- 1beta production. Progesterone also reduced IL-1alpha and IL-1beta production significantly at concentrations of 0.1 ng/ml or more and 0.02 ng/ml or more, respectively. The reductions in IL- 1alpha and IL-1beta production by sex hormones were not affected by addition of indomethacin.

CONCLUSIONS

Estradiol and progesterone inhibited the production of IL-1 from human peripheral monocytes. The inhibition was not the result of enhanced production of PGE2. Under conditions in which sex hormone levels are low, monocytes produce IL- more readily in response to stimulation by LPS than high levels of such hormones. Low concentrations of sex hormones may be considered as one of the risk factors for periodontitis.

Performance and digestibilities of beef cattle fed diets supplemented with either soybean meal or roasted soybeans and implanted with Synovex

Two 160-d feedlot experiments, each consisting of 20 Angus-Hereford steers (216 +/- 5 kg BW, Exp. 1; 258 +/- 5 kg BW, Exp. 2) and 20 Angus-Hereford heifers (208 +/- 5 kg BW, Exp. 1; 236 +/- 5 kg BW, Exp. 2), were used to investigate the effects of supplementing diets with either roasted soybeans (RSB, roasted at 127 degrees C for 10 min) or soybean meal (SBM) and implanting or not implanting with an estrogenic growth promoter (SYN; Synovex-S, 20 mg of estradiol benzoate plus 200 mg of progesterone or Synovex-H, 20 mg of estradiol benzoate plus 200 mg of testosterone) on performance. The cattle were fed a basal diet of 15% orchardgrass silage, 15% corn silage, and 70% corn-based concentrate. Treatments were 1) no SYN and fed a SBM-supplemented diet, 2) no SYN and fed a RSB-supplemented diet, 3) SYN and SBM, and 4) SYN and RSB. Cattle in the SYN groups were reimplanted at 80 d. Four additional Angus-Hereford steers were used in a digestion and nitrogen balance experiment conducted during the first half of Exp. 1. For the total 160-d feedlot experiments, DMI for RSB compared with SBM was lower (P < .01; 8.5 vs 9.2 kg/d, SEM = .07) and ADG/DMI tended to be higher (P < .10; 165 vs 157 g/kg, SEM = 1.3). Final BW of steers fed RSB was similar (P > .10) to that of steers fed SBM (473 vs 478 kg, SEM = 5.6), as was ADG (1.39 vs 1.43 kg/d, SEM = .02). Dry matter intake for SYN-implanted steers was higher (P < .01) than for steers not implanted (9.2 vs 8.5 kg/d). Likewise, final BW (491 vs 460 kg) and ADG (1.49 vs 1.33 kg/d) were higher (P < .01), and ADG/DMI (166 vs 157 g/kg) tended to be higher (P < .10), for SYN-implanted steers than for steers not implanted. During the more rapid muscle growth period (0 to 80 d), DMI for RSB compared with SBM was lower (P < .01; 7.8 vs 8.6 kg/d, SEM = .07) and ADG/DMI was similar (P > .10; 181 vs 172 g/kg, SEM = 1.8). Dry matter intake for SYN-implanted steers was higher (P < .05) than for steers not implanted (8.4 vs 8.0 kg/d), as was ADG/DMI (P < .01, 182 vs 171 g/kg). During this more rapid growth period, the supplement x implant interaction for ADG was significant (P < .05; 1.35, 1.36, 1.59, and 1.44 kg/d for Treatments 1, 2, 3, and 4, respectively, SEM = .04). There were no differences in digestibilities or N balance. The results suggest that there is no improvement in performance under feedlot conditions when RSB replaces SBM in the diet of beef cattle, and, in young cattle, RSB may reduce the response expected by an estrogenic growth promoter.

Progesterone reduces immobility in rats forced to swim

BACKGROUND

Among its behavioral actions, progesterone reduces anxiety in several species including humans; however, any antidepressant-like properties remain to be explored.

METHODS

In the present study, Wistar rats received injections (i.p.) of progesterone (0.20-3.0 mg/kg) 24 and 2 h before being submitted to the forced swim, a test in which antidepressants regularly reduce immobility and exert few or no actions on locomotor activity. In order to discard the cumulative effects of progesterone and a possible effect from the repetition of the swimming test, all animals received one of several progesterone doses in a different sequence following a completely randomized experimental intrasubject design.

RESULTS

Ovariectomy did not modify immobility in the forced swim test as compared to control tests practiced before surgery. A dose of 0.80 mg/kg strongly reduced the total time of immobility in forced swim test (p < 0.001), but did not modify locomotor activity. In a drug-free control test applied 1 week after the last injection of progesterone, immobility returned to the higher values observed in the control tests.

CONCLUSIONS

From these results, it is concluded that progesterone may possess some anti-depressant-like activity.

Transvaginal progesterone: evidence for a new functional 'portal system' flowing from the vagina to the uterus

The results of many recent experimental and clinical studies support the hypothesis that progesterone administered vaginally is distributed selectively to the uterus where tissue concentrations and effects exceed expectations. This phenomenon has multiple clinical implications in several fields of gynaecological endocrinology, notably in assisted reproductive treatments and new forms of hormone replacement therapy. Yet, the actual mechanisms by which vaginal administration of progesterone can induce higher concentrations in the uterus, despite low concentrations in the systemic circulation, remain obscure and most puzzling to many gynaecologists. This review aims to muster ideas and propose different mechanisms to explain the observed phenomenon. In particular, we will summarize data that support the various putative modes of transport including, direct diffusion through tissue, intracervical aspiration, absorption into the venous or lymphatic circulatory systems and countercurrent vascular exchange with diffusion from utero-vaginal veins/lymph vessels to arteries. All these mechanisms may concur to various extents to the uterine specificity of vaginal progesterone.

The effect of roasted soybeans in the diet of feedlot steers and Synovex-S ear implants on carcass characteristics and estimated composition

Beef steer carcasses from three 2 x 2 factorial feeding experiments (Exp. 1, 20 carcasses; Exp. 2 and 3, 19 carcasses each) were evaluated to study the influence of supplementing with roasted soybeans (RSB; 127 degrees C for 10 min) vs soybean meal (SBM) and implanting with the estrogenic growth promoter Synovex-S (SYN, 20 mg estradiol benzoate and 200 mg progesterone) on carcass merit, composition of dissected 9-10-11th rib section, estimated edible carcass composition, and cooking characteristics of strip loin steaks. In all experiments, steers were fed diets consisting of 15% corn silage, 15% orchardgrass silage, and 70% corn-based concentrate. There were no treatment interactions found in this study. Final BW averaged 480.4, 498.5, and 500.7 kg for Exp. 1, 2, and 3, respectively, and hot carcass weights averaged 288.4, 296.4, and 309.1 kg. Across experiments, hot carcass weight was 8.3 kg less (P < .03) for RSB steers than for SBM steers. Fat weight (P < .01) and percentage of fat (P < .01) were less and percentage of bone (P < .04) was greater in the 9-10-11th rib section of RSB steers than of SBM steers. Estimated percentage of fat (P < .02) was less and percentage of bone (P < .04) was greater in edible carcass of RSB steers than in that of SBM steers. Total 9-10-11th rib section weight tended to be less for RSB steers (P < .08) than for SBM steers. Carcass merit measurements were not affected (P > .10) by supplement, but numerically the percentage of kidney, pelvic, and heart fat was 11% greater for RSB steers than for SBM steers in Exp. 2 and 3. Final BW and carcass weight were 38.7 and 22.6 kg greater (P < .01), respectively, for SYN-implanted steers than for steers not implanted. Longissimus muscle area was greater (P < .01), percentage of kidney, pelvic, and heart fat (P < .02) was less, USDA quality grade tended to be less (P < .09), and shear force of strip loin was greater (P < .01) for SYN-implanted steers than for steers not implanted. The 9-10-11th rib section and estimated carcass compositions were not different (P > .10) between SYN-implanted steers and steers not implanted but reflected a somewhat leaner carcass. The authors conclude from this study that in feedlot steers, either implanted or not implanted, there is no benefit from supplementing with RSB in place of SBM, and that the use of RSB in place of SBM in feedlot diets may reduce the amount of edible carcass.