Effects of steroids on endometrial oxytocin mRNA production

In this study, the roles of oestrogen and progesterone in the regulation of oxytocin gene expression in equine endometrium were examined. Anoestrous mares (n=19) were assigned randomly to one of the following treatment groups: control (vehicle control for 1 day; n=3); progesterone (250 mg progesterone per day for 6 days; n=4); oestradiol (5 mg beta-oestradiol 17-valerate per day for 6 days; n=4); oestradiol plus short duration progesterone (5 mg beta-oestradiol 17-valerate per day for 6 days followed by 250 mg progesterone per day for 6 days; n=4); and oestradiol plus long duration progesterone (5 mg beta-oestradiol 17-valerate per day for 6 days followed by 250 mg progesterone per day for 12 days; n=4). Jugular venous blood samples were obtained for oestrogen and progesterone radioimmunoassays. Endometrial biopsies were obtained and total RNA was extracted. Expression of mRNA for oxytocin and glyceraldehyde 3'-phosphate dehydrogenase was assessed by RT-PCR and Southern blotting. Oxytocin mRNA abundance was significantly higher (P < 0.05) in the oestrogen-treated group than in all other groups. These data demonstrate that oestradiol priming for 6 days upregulated expression of the endometrial oxytocin gene. Progesterone treatment for either 6 or 12 days after oestradiol priming returned oxytocin mRNA abundance to levels similar to those of controls.

Long-term treatment with estrogen and progesterone enhances acquisition of a spatial memory task by ovariectomized aged rats

Female Sprague-Dawley rats were ovariectomized at 13 months of age. Four groups received different regimens of estrogen or estrogen plus progesterone replacement beginning either immediately, 3 months, or 10 months after ovariectomy and were compared with non-hormone-treated controls. Eight to twelve months after ovariectomy, animals were trained on a delayed matching-to-position (DMP) spatial memory task. Long-term treatment with estrogen or estrogen plus progesterone significantly enhanced acquisition of the DMP task by aged animals after long-term loss of ovarian function. Weekly administration of estrogen and progesterone was at least as effective as, if not more effective than, continuous treatment with estrogen alone. In addition, treatment initiated 3 months, but not 10 months, after ovariectomy was as effective at enhancing DMP acquisition as continuous estrogen treatment initiated immediately after ovariectomy, suggesting a window of opportunity after the loss of ovarian function during which hormone replacement can effectively prevent the effects of aging and hormone deprivation on cognitive function. These findings suggest that repeated treatment with estrogen and progesterone initiated within a specific period of time after the loss of ovarian function may be effective at preventing specific negative effects of hormone deprivation on brain aging and cognitive decline.

Neuroprotective effects of female gonadal steroids in reproductively senescent female rats

BACKGROUND AND PURPOSE

Young adult female rats sustain smaller infarcts after experimental stroke than age-matched males. This sex difference in ischemic brain injury in young animals disappears after surgical ovariectomy and can be restored by estrogen replacement. We sought to determine whether ischemic brain injury continues to be smaller in middle-aged, reproductively senescent female rats compared with age-matched males and to test the effect of ovarian steroids on brain injury after experimental stroke in females.

METHODS

Four groups of 16-month old Wistar rats (males [n=9], untreated females [n=9], and females pretreated with 17beta-estradiol [25-microgram pellets administered subcutaneously for 7 days; n=9] or progesterone [10-mg pellets administered subcutaneously for 7 days; n=9] were subjected to 2 hours of middle cerebral artery occlusion with the intraluminal filament technique, followed by 22 hours of reperfusion. Physiological variables and laser-Doppler cerebral cortical perfusion were monitored throughout ischemia and early reperfusion. In a separate cohort of males (n=3), untreated females (n=3), females pretreated with 17beta-estradiol (n=3), and females pretreated with progesterone (n=3), end-ischemic regional cerebral blood flow was measured by [(14)C]iodoantipyrine autoradiography.

RESULTS

As predicted, infarct size was not different between middle-aged male and female rats. Cortical infarcts were 21+/-5% and 31+/-6% of ipsilateral cerebral cortex, and striatal infarcts were 44+/-7% and 43+/-5% of ipsilateral striatum in males and females, respectively. Both estrogen and progesterone reduced cortical infarct in reproductively senescent females (5+/-2% and 16+/-4% in estrogen- and progesterone-treated groups, respectively, compared with 31+/-6% in untreated group). Striatal infarct was smaller in the estrogen- but not in the progesterone-treated group. Relative change in laser-Doppler cerebral cortical perfusion from preischemic baseline and absolute end-ischemic regional cerebral blood flow were not affected by hormonal treatments.

CONCLUSIONS

We conclude that the protection against ischemic brain injury found in young adult female rats disappears after reproductive senescence in middle-aged females and that ovarian hormones alleviate stroke injury in reproductively senescent female rats by a blood flow-independent mechanism. These findings support a role for hormone replacement therapy in stroke injury prevention in postmenopausal women.

Embryo survival, uterine fluids and tubal SEM in progesterone-asynchronized rabbits

Survival of embryos exposed to several concentrations of uterine proteins and changes in tubal morphology in rabbits given low preovulatory doses of progesterone (P4) that had previously not affected ovulation or fertilization, but caused severe embryo mortality, were studied. In experiment 1, 332 morulae were cultured for 24 h in a control medium containing < 0.5 to > 3.0 mg x mL(-1) of Day 3 uterine fluid proteins. There was no difference in blastocyst development nor implantation to Day 12 following transfer of the blastocysts to recipients, except fewer implants developed in the BSA control. In experiment 2 the oviducts and uteri of control and P4-treated does were examined by SEM for 8 days following ovulation. Secretory cells in the oviducts and to a lesser extent in the uteri were stimulated by P4 treatment for 3 to 4 days after ovulation. Morphology of ciliated cells was unaffected. The subtle changes did not fully account for P4-induced embryo mortality in vivo.

Biodegradable progesterone microsphere delivery system for osteoporosis therapy

The purpose of this study was to formulate and characterize a controlled-release biodegradable delivery system of progesterone for the treatment or prevention of osteoporosis. Microspheres of progesterone were formulated using copolymers of poly(glycolic acid-co-dl-lactic acid) (PGLA 50/50 and PGLA 15/85) and poly(L-lactic acid) (L-PLA) of similar molecular weight by the emulsion solvent evaporation technique. The effects of process variables, such as volume fraction, polyvinyl alcohol (PVA) concentration, polymer composition, and stir speed during preparation, on the yield, encapsulation efficiency (EEF), particle size distribution, in vitro release profiles of progesterone, and surface morphology of progesterone microspheres were investigated. Increasing the volume fraction from 9% to 22% increased the EEF without significantly increasing the yield; however, the rate of progesterone release from the microspheres decreased. Increasing the PVA concentration from 1% to 5% had no significant influence on the EEF, but the rate of progesterone release from microspheres increased. Polymer composition had no significant effect on the EEF, but had a significant effect on the particle size distribution, surface morphology, and release rate of progesterone from the microspheres. Stir speed did not have a significant influence on the EEF; however, stir speed influenced particle size distribution and the rate of progesterone release from microspheres of the same sieve-size range. The results suggest that controlled release of progesterone is possible by varying the different process variables, and that PGLA 50/50 provided the slowest release of progesterone. This should provide a means of delivering progesterone for months for the treatment or prevention of osteoporosis in postmenopausal women.

Endocrine alterations that underlie endotoxin-induced disruption of the follicular phase in ewes

Two experiments were conducted to investigate endocrine mechanisms by which the immune/inflammatory stimulus endotoxin disrupts the follicular phase of the estrous cycle of the ewe. In both studies, endotoxin was infused i.v. (300 ng/kg per hour) for 26 h beginning 12 h after withdrawal of progesterone to initiate the follicular phase. Experiment 1 sought to pinpoint which endocrine step or steps in the preovulatory sequence are compromised by endotoxin. In sham-infused controls, estradiol rose progressively from the time of progesterone withdrawal until the LH/FSH surges and estrous behavior, which began approximately 48 h after progesterone withdrawal. Endotoxin interrupted the preovulatory estradiol rise and delayed or blocked the LH/FSH surges and estrus. Experiment 2 tested the hypothesis that endotoxin suppresses the high-frequency LH pulses necessary to stimulate the preovulatory estradiol rise. All 6 controls exhibited high-frequency LH pulses typically associated with the preovulatory estradiol rise. As in the first experiment, endotoxin interrupted the estradiol rise and delayed or blocked the LH/FSH surges and estrus. LH pulse patterns, however, differed among the six endotoxin-treated ewes. Three showed markedly disrupted LH pulses compared to those of controls. The three remaining experimental ewes expressed LH pulses similar to those of controls; yet the estradiol rise and preovulatory LH surge were still disrupted. Our results demonstrate that endotoxin invariably interrupts the preovulatory estradiol rise and delays or blocks the subsequent LH and FSH surges in the ewe. Mechanistically, endotoxin can interfere with the preovulatory sequence of endocrine events via suppression of LH pulsatility, although other processes such as ovarian responsiveness to gonadotropin stimulation appear to be disrupted as well.

17beta-estradiol acts separately on the LDL particle and artery wall to reduce LDL accumulation

Estrogen replacement therapy has been shown to attenuate atherogenesis, although the mechanisms for this effect are incompletely defined. Previously, we showed that 17-beta estradiol (estradiol) attenuated oxidant stress-induced increases in vascular low density lipoprotein (LDL) accumulation. It was unclear whether estradiol's effect was imparted on the lipoprotein particle or the artery wall. To examine this, we chronically treated rats with the following sex hormones: low estradiol, high estradiol, progesterone, low estradiol + progesterone, placebo, or control. Carotid arteries (n = 8/group) were isolated and perfused with fluorescently labeled LDL. Rates of LDL accumulation were measured before and after treatment with 10 ng/ml tumor necrosis factor-alpha (TNF) using quantitative fluorescence microscopy. We observed a 50% decrease in basal LDL accumulation rates (P < 0.01) and a 25% decrease in endothelial layer permeability (P < 0.01) in arteries from estradiol-treated animals. There was no effect of hormone replacement on rate of TNF-induced LDL accumulation (P = 0.451), while incubation of LDL with 65 pg/ml estradiol attenuated the TNF effect (P < 0.01). These experiments suggest two independent mechanisms of anti-atherogenic protection by estradiol: 1) decreased endothelial layer permeability; and 2) incorporation of estradiol into the LDL particle and prevention of LDL binding to the artery wall.

Estroprogestin vs. gonadotrophin agonists plus estroprogestin in the treatment of endometriosis-related pelvic pain: a randomized trial. Gruppo Italiano per lo Studio dell'Endometriosi

OBJECTIVE

This is a randomized clinical trial comparing estroprogestin (E/P) pill given for 12 months vs. gonadotrophin releasing hormone agonist (GNRHa) given for 4 months followed by E/P pill treatment for 8 months in the relief of endometriosis-related pelvic pain.

METHODS

Eligible for the study were women with laparoscopically confirmed endometriosis and pelvic pain lasting 3-12 months after diagnosis. Eligible women were randomly assigned to treatment with E/P pill (gestroden 0.75 mg and ethynlestradiol 0.03 mg) for 12 months (47 patients) vs. tryptorelin 3.75 mg slow release every 28 days for 4 months followed by E/P pill for 8 months (55 patients).

RESULTS

At baseline, dysmenorrhea was reported in 46 women allocated to E/P pill only (97.9%), and in all the 55 women allocated to GNRHa+E/P pill. The corresponding value at the 12 months follow-up visit was 14 subjects (35.9%) and 16 subjects (34.8%). The baseline median values of the multidimensional and analog scale were for dysmenorrhea 4 and 6 in the EP only and 3 and 6 in the GNRHa+E/P group. The corresponding value at the 12 months follow-up visit were 2 and 6 and 0 and 5. Non-menstrual pain was reported, respectively, at baseline and 12 month visit by 46 (97.9%) and 15 (38.5%) subjects in the E/P pill group and 49 (89.1%) and 17 (37.0%) of the GNRHa+E/P pill one. The baseline median values of the multidimensional and analog scale were for non-menstrual pain 3 and 5 in the E/P only and 2 and 6 in the GNRHa+E/P group. The corresponding values at the 12 month follow-up visit were 0 and 4 and 0 and 4. These differences between the two groups were not statistically significant.

CONCLUSIONS

1 year after randomization, the two treatment schedules show similar relief of pelvic pain in women with endometriosis.

Novel delivery systems in contraception

Contraception has mainly remained the responsibility of women. The sexually active time during the fertile period of life may last over 30 years and, increasingly, it is more than 10 years before the first baby. It is, therefore, natural that convenient long-acting contraceptive methods are becoming more and more appealing. The discovery of poly(dimethylsiloxane) as a carrier, and controlled release polymers for small molecule drugs allowed the development of contraceptive devices releasing steroids for several years. While contraceptive implants and intra-uterine systems are already marketed in many countries, contraceptive vaginal rings are in their late development phase. The key features of these long acting delivery systems are convenience, efficacy, reversibility and positive long-term health effects. Since these methods are based on new concepts, the provider needs to be prepared for extensive counselling.

Hormonal replacement regimens and bleeding

Hormone replacement therapy may increase the quality of life of postmenopausal women. Any regimen need to offer long-term endometrial safety. It is a standard to consider the co-administration of a sequential progestogen when estrogen replacement should be initiated in non-hysterectomized women. It is almost impossible to decide which combination of an estrogen and a progestogen seems to be optimal as individual tolerance of HRT may very well limit acceptability despite metabolic benefits and proven endometrial safety of a given combination. Several combinations of oral and transdermal estradiol or conjugated equine estrogens, oral progestogens, transdermal norethisterone acetate and levonorgestrel, and intrauterine levonorgestrel may achieve endometrial safety. It is noteworthy that there is no uniform correlation between the timing of onset of bleeding induced by any sequential estrogen and progestogen replacement and a certain pattern of histology. Therefore, although it is likely, there is no absolute reassurance that regular bleeding on or after day 11 of progestogen administration rules out abnormal histopathology. Transvaginal sonography seems not to be of pivotal importance to screen asymptomatic women on replacement therapy for detection of serious abnormal endometrial findings such as hyperplasia and endometrial cancer. Continuous combined hormone replacement therapy or the use of tibolone may be an alternative in postmenopausal women, who do not want any uterine bleedings after menopause. However, spottings or bleedings most often occur at the beginning of treatment. Vaginal administration of estriol and estradiol for urogenital symptoms of estrogen deficiency may stimulate the endometrium unintentionally. Available data suggest that use of oral estriol may be associated with endometrial hyperplasia and endometrial carcinoma relatively more often compared to sequential HRT. Raloxifene, a benzothiophene derivative acting as a selective estrogen receptor modulator approved for prevention of vertebral osteoporosis, rarely causes uterine bleeding. There is no ideal therapy available to suit women looking for a permanently bleed-free hormonal replacement therapy today.

Progesterone/progestogen releasing intrauterine systems versus either placebo or any other medication for heavy menstrual bleeding

BACKGROUND

Heavy menstrual bleeding (HMB) is an important cause of ill health in women and it accounts for 12% of all gynaecology referrals in the UK. Heavy menstrual bleeding is clinically defined as greater than, or equal to, 80mls blood loss per menstrual cycle but women may complain of excessive bleeding when their blood loss is less than 80ml. Hysterectomy is often used to treat women with this complaint but medical therapy may be a successful alternative. The intrauterine coil device was originally developed as a contraceptive but the addition of uterine relaxing hormones, or progestogens, to these devices resulted in a large reduction in menstrual blood loss. Case studies of 2 types of progesterone/progestogen releasing systems, Progestasert and Mirena, report reductions of up to 90% and dysmenorrhoea may be improved. Insertion, however, may be regarded as invasive by some women affecting its acceptability as a treatment and frequent intermenstrual bleeding and spotting is likely during the first few months.

OBJECTIVES

To determine the effectiveness and acceptability of progesterone/progestogen-releasing intrauterine devices in achieving a reduction in heavy menstrual bleeding.

SEARCH STRATEGY

All studies which might describe randomised controlled trials of progesterone/progestagen-releasing intrauterine devices for the treatment of heavy menstrual bleeding were obtained by electronic searches of the MEDLINE 1966-1999, EMBASE 1980-1999 databases and the Cochrane Library. Companies producing progestogen releasing intrauterine devices and experts in the field were contacted for information on published and unpublished trials.

SELECTION CRITERIA

Randomised controlled trials in women of reproductive age treated with progesterone/progestogen-releasing intrauterine devices versus no treatment, placebo, or other medical or surgical therapy for heavy menstrual bleeding within either the primary care, family planning or specialist clinic setting were eligible for inclusion. Women with postmenopausal bleeding, intermenstrual or irregular bleeding, or pathological causes of heavy menstrual bleeding were excluded.

DATA COLLECTION AND ANALYSIS

Potential trials were independently assessed by three reviewers and five trials met the criteria for inclusion in the review. The reviewers extracted the data independently and data were pooled where appropriate. Odds ratios for dichtomous outcomes and weighted mean differences for continuous outcomes were estimated from the data. The primary outcome was reduction in menstrual blood loss but incidence of side effects, changes in quality of life and satisfaction and acceptability measures were also assessed.

MAIN RESULTS

Progesterone/progestogen-releasing intrauterine systems have not been compared to placebo or no treatment. Progestasert has been compared to a number of different medical therapies in one small study but no conclusions can be made about effectiveness. The levonorgestrel-releasing intrauterine device (LNG IUS) has been compared to oral cyclical norethisterone (NET) administered on days 5-26 in one trial and was significantly more effective although there was a large reduction from baseline in both groups and these differences were not perceived by the women undergoing the treatment. Some side effects were more common in the LNG IUS group but a significantly greater proportion of women in this group were satisfied and willing to continue with their treatment. In one trial of women awaiting hysterectomy where the LNG IUS was compared with a control group taking their existing medical therapy, a higher proportion of the women in the former group cancelled their planned surgery after 6 months of treatment. The levonorgestrel-releasing intrauterine device has been compared to a surgical procedure (transcervical resection of the endometrium (TCRE)) in two trials. (ABSTRACT TRUNCATED)

Estradiol/progesterone substitution in the luteal phase improves pregnancy rates in stimulated cycles--but only in younger women

Innumerable studies have attempted to demonstrate that hormonal support of the luteal phase during ovulation induction cycles improves pregnancy rates. None has, however, so far been able to confirm the validity of such treatment conclusively, possibly because most studies only utilized progesterone substitution. Since luteal phase endometrium also requires estradiol support, this study attempted to investigate whether hormone substitution with progesterone and estradiol would be more successful in improving pregnancy rates. Amongst approximately 7500 consecutive ovulation induction cycles were identified prospectively which were characterized by a precipitous drop of luteal phase serum estradiol levels by more than 50% over a 48 hour period within 10 days from hCG administration. Those cycles were prospectively randomized to oral micronized estradiol substitution (Group I) or not (Group II), while both groups received routine progesterone substitution of the luteal phase. Cycles were then evaluated in regards to the occurrence of chemical, ectopic and clinical pregnancies. One hundred sixty-three Group I cycles resulted in 34 pregnancies (20.9%), which compared favorably to 21 pregnancies in 167 Group II patients (12.6%) (x2[1] = 4.06; p < 0.04). The advantage for Group I cycles (29/95 pregnancies, 31%) vs. Group II cycles (16/105, 15%) became even more pronounced when only women up to age 35 years were evaluated. Estradiol substitution maintained a significant advantage until age 38 (x2 [1] = 6.87; p < 0.009). While gravidity did not affect pregnancy success, estradiol substitution in Group I benefited nulliparous (23% pregnancy rate) over multiparous women (12% pregnancy rate) (x2 [2] = 6.86; p< 0.03). This association was, however, age-dependent. A combined estradiol and progesterone substitution of the luteal phase of ovulation induction cycles increases the overall pregnancy rate. Since estradiol substitution was initiated in this study only once a precipitous drop in serum estradiol levels had already taken place, an even larger improvement in pregnancy rates could conceivably be possible if earlier estradiol substitution of the luteal phase is initiated. A further expansion of investigations of similar protocols for routine ovulation induction and in vitro fertilization (IVF) cycles may be indicated, especially in women below age 38 years and in nulliparous females.

Emergency contraception

High rates of adolescent pregnancy remain a challenge for health care providers. For most sexually active adolescents, pregnancy is unintended. Emergency contraception, also called the "morning-after-pill" or postcoital contraception, is a way to prevent pregnancy after unprotected intercourse. In the United States, three forms of emergency contraception currently are available: high-dose combination estrogen and progestin pills, high-dose progestin-only pills, and postcoital insertion of a copper intrauterine device. The postcoital intrauterine device is used infrequently. When emergency contraceptive pills (ECPs) are taken within 72 hours of unprotected intercourse, they reduce the risk of pregnancy by at least 75%. However, they are most effective if taken within 24 hours of coitus. Eleven brands of pills currently are marketed in the United States that conform to the regimens approved by the Food and Drug Administration (FDA) for this indication. Recently, two prepackaged ECPs were approved by the FDA. The only medical contraindication to prescribing ECPs is pregnancy. The most common side effects are nausea and vomiting, followed by menstrual disturbances, breast tenderness, abdominal cramping, dizziness, headache, and mood changes. Because vomiting can compromise the efficacy of ECPs, routine pretreatment with an antiemetic is recommended. Primary care providers can reduce unintended adolescent pregnancy by routinely counseling adolescents at all office visits about the existence of emergency contraception and by prescribing it in advance and over the telephone.

Synchronization of oestrous cycles in sable antelope

Techniques for manipulating the oestrous cycle of sable antelope, Hippotragus niger, were evaluated in a captive population of 24 females maintained at the Smithsonian Institution's Conservation and Research Center in Front Royal, VA, USA. A secondary objective was to demonstrate the effectiveness of fecal steroid monitoring techniques as a non-invasive method of tracking experimental manipulations. Controlled Internal Drug Releasing (CIDR) devices designed for cattle (type B, reduced in length by 5 cm to fit the sable antelope's smaller reproductive tract) were more effective than CIDR devices designed for goats (type G) at delivering progesterone into circulation, and maintained serum progesterone at levels up to 86.1+/-7.8% of normal luteal concentrations in females whose spontaneous ovarian activity had been inhibited with melengestrol acetate. Serum progesterone and fecal progestagen measurements were highly correlated (P<0.05). Synchronization treatments of prostaglandin (PG) F2alpha alone and in combination with modified CIDR-B devices (12-day insertion interval) were both effective in inducing synchronized ovulation, however the PGF2alpha/modified CIDR-B treatment resulted in more precise synchrony and a shorter latency to ovulation than did PGF2alpha alone. In a separate experiment to characterize the temporal relationship between synchronization treatment, behavioral oestrus and ovulation, onset of behavioral oestrus occurred 34.1+/-5.7 h following PGF2alpha/modified CIDR-B treatment. Mean duration of the induced oestrus was 24.9+/-4.3 h. The first detectable rise in fecal progestagens occurred 5.1+/-1.0 and 4.1+/-1.0 days following PGF2alpha/modified CIDR-B treatment in groups of females housed with and without an adult male, respectively, indicating that the presence of a male did not accelerate the onset of the induced cycle.

Estrogen and progesterone reduce lipid accumulation in human monocyte-derived macrophages: a sex-specific effect

BACKGROUND

Males have an earlier onset and greater prevalence of clinical atherosclerosis than age-matched females, which is consistent with an atheroprotective effect of the female sex steroids, estrogen and progesterone. We therefore examined the effects of estrogen and progesterone on human foam cell formation, a key early event in atherogenesis.

METHODS AND RESULTS

Monocytes from healthy female and male donors were obtained from white cell concentrates and allowed to differentiate into macrophages over 10 days. These human monocyte-derived macrophages (MDMs) were exposed to either control (0.1% vol/vol ethanol) or estrogen or progesterone treatment on days 3 through 10. Lipid loading was achieved on days 8 through 10 by incubation with acetylated LDL. Lipid from the MDMs was then extracted for analysis of cholesteryl ester (CE) content. 17beta-Estradiol at both physiological (2 nmol/L) and supraphysiological (20 and 200 nmol/L) concentrations produced a significant reduction in macrophage CE content (88+/-3%, 88+/-2%, and 85+/-4%, respectively; P<0.02 compared with control). Physiological and supraphysiological levels of progesterone (2, 10, and 200 nmol/L) produced an even more dramatic reduction in CE content (74+/-9%, 56+/-10%, and 65+/-8%, respectively; P<0.002 compared with control). This effect could be abrogated by coincubation with the progesterone receptor antagonist RU486. Neither estrogen nor progesterone produced a reduction in lipid loading in male-donor-derived MDMs. Detailed lipid trafficking studies demonstrated that both estrogen and progesterone altered macrophage uptake and/or processing of modified LDL.

CONCLUSIONS

Physiological levels of estrogen and progesterone are associated with a female-sex-specific reduction in human macrophage lipid loading, which is consistent with an atheroprotective effect.

Effects of postnatal estradiol and progesterone replacement in extremely preterm infants

The fetus is supplied from the placenta with estradiol (E2) and progesterone (P) in increasing amounts during gestation. After delivery of a premature infant, placental supply is disrupted, resulting in a rapid decrease in E2 and P. Replacement of these placental hormones may restore intrauterine conditions and may be beneficial for bone mineral accretion, clinical course, and outcome. Thirty female infants with a median gestational age of 26.6 weeks (between 24.1-28.7) and a birth weight of 675 g (370-990) were randomized to receive E2 and P replacement, aiming to maintain plasma levels equaling the intrauterine levels, or no replacement. The E2 and P replacement was started iv and was followed by transepidermal administration for a total duration of 6 weeks. Repeated measurements included plasma levels of E2, P, FSH, and LH; uterine volume; calcium and phosphorus in spot urine specimens; and bone mineral accretion by single photon absorption densitometry. Further, the incidence of chronic lung disease and various clinical outcome data were recorded. The plasma levels of E2 and P were within the intrauterine range with median replacements of 2.30 mg/kg x day E2 (1.13-6.23) and 21.20 mg/kg x day P (11.23-27.36), iv. Three- and 6-fold higher doses of E2 and P were needed via the transepidermal route. The uterine volumes increased, and FSH and LH as indicators for biological effectiveness were significantly lowered with replacement. The bone mineral accretion rates tended to be higher, and the incidence of chronic lung disease tended to be lower (0% vs. 29%; P = 0.097). E2 and P replacement via iv and transepidermal routes is capable of maintaining plasma levels as high as those in utero with biological effectiveness. Trends toward improved postnatal bone mineral accretion and less chronic lung disease were found with the hormone replacement. Further and more extensive studies are warranted to address the role of this new approach in the care of extremely premature infants.

Role of luteinizing hormone in follicle deviation based on manipulating progesterone concentrations in mares

The effects of several doses of progesterone on FSH and LH concentrations were used to study the role of the gonadotropins on deviation in growth rates of the two largest follicles during the establishment of follicle dominance. Progesterone was given to pony mares at a daily dose rate of 0 mg (controls), 30 mg (low dose), 100 mg (intermediate dose), and 300 mg (high dose). All follicles > or = 6 mm were ablated at Day 10 (Day 0 = ovulation) to initiate a new follicular wave; prostaglandin F(2alpha) was given to induce luteolysis, and progesterone was given from Days 10 to 24. The low dose did not significantly alter any of the ovarian or gonadotropin end points. The high dose reduced (P < 0.05) the ablation-induced FSH concentrations on Day 11. Maximum diameter of the largest follicle (17.2 +/- 0.6 mm) and the second-largest follicle (15.5 +/- 0.9 mm) in the high-dose group was less (P < 0.04) than the diameter of the second-largest follicle in the controls (20.0 +/- 1.0 mm) at the beginning of deviation (Day 16.7 +/- 0.4). Thus, the growth of the two largest follicles was reduced by the high dose, presumably through depression of FSH, so that the follicles did not attain a diameter characteristic of deviation in the controls. The intermediate dose did not affect FSH concentrations. However, the LH concentrations increased in the control, low, and intermediate groups, but then decreased (P < 0.05) in the intermediate group to pretreatment levels. The LH decrease in the intermediate group occurred 2 days before deviation in the controls. The maximum diameter of the largest follicle was less (P < 0.0001) in the intermediate group (27.3 +/- 1.8 mm) than in the controls (38.9 +/- 1.5 mm), but the maximum diameter of the second-largest follicle was not different between the two groups (19.0 +/- 1.1 vs. 20.3 +/- 1.0 mm). Thus, the onset of deviation, as assessed by the second-largest follicle, was not delayed by the decrease in LH. Diameter of the largest follicle by Day 18 in the intermediate group (23.1 +/- 1.6 mm) was less (P < 0.05) than in the controls (28.0 +/- 1.0 mm). These results suggest that circulating LH was not involved in the initiation of dominance (inhibition of other follicles by the largest follicle) but was required for the continued growth of the largest follicle after or concurrently with its initial expression of dominance.

Implant sequence effects in intact male Holstein veal calves: carcass characteristics

Seven sequences of growth promotant implants were used in intact male Holstein veal calves (n = 443). Implants were administered on d 0 (within 4 d after arrival at the veal barn), 42, and 84. The implants used were placebo (0), Z (36 mg zeranol), ET (20 mg estradiol, 200 mg testosterone), EP/2 (10 mg estradiol, 100 mg progesterone), EP (20 mg estradiol, 200 mg progesterone), and EBA (24 mg estradiol, 120 mg trenbolone acetate). The following sequences were compared: 0-0-0 (negative control), 0-ET-ET, Z-ET-ET, 0-EP-EP, Z-EP-EP, 0-EP/2-EBA, and Z-0-EBA. Sequences 0-EP-EP, Z-EP-EP, and 0-EP/2-EBA increased (P<.05) carcass weight from 3.3 to 3.9% compared to nonimplanted controls. There were no differences (P>.05) in percentage of carcass weight accounted for by the fore vs. rear halves of carcasses, suggesting there was no difference in the distribution of weight. Although there were differences in longissimus area, the results were not consistent, except that there was a trend for longissimus area to be increased by the use of estrogenic-androgenic implants (ET and EBA). There were no differences among implant sequences for carcass conformation, fat cover, muscle texture, marbling/ feathering, muscle color, or muscle chemical composition. Of four implant sequences (0-0-0, 0-ET-ET, 0-EP-EP, and 0-EP/2-EBA) tested for differences in Warner-Bratzler shear force tenderness, the latter two sequences averaged higher (P<.05) for shear force than did the negative control. These results suggest that aggressive implant strategies in young, intact Holstein bull calves (raised as veal) have minimal effects on carcass characteristics.

Neuroprotective effects of progesterone after transient middle cerebral artery occlusion in rat

Treatment of focal cerebral ischemia in the rat with intraperitoneal administration of progesterone dissolved in dimethyl sulfoxide (DMSO) has demonstrated therapeutic efficacy. In the present study we test whether iv administration of water soluble progesterone 2 h after the onset of middle cerebral artery occlusion provides therapeutic benefit for the treatment of stroke. In addition, we perform a battery of functional tests: rotarod, adhesive-backed somatosensory, and neurological score, as well as a dose-response study. The data indicate that iv administration of progesterone at a dose of 8 mg/kg significantly reduces the volume of cerebral infarction and significantly improves outcome on the array of functional measures employed. Treatment with 4 mg/kg or 32 mg/kg of progesterone failed to provide any therapeutic benefit. Progesterone, a non toxic, clinically employed, pluripotent therapeutic agent which targets both neuroprotective as well as neuroregenerative strategies, may have important therapeutic benefits for the treatment of stroke.

Implant sequence effects in intact male Holstein veal calves: live and slaughter traits

Seven sequences of growth promotant implants were used in special-fed intact male Holstein veal calves (n = 443). Calves received implants 4 d after arrival at the veal barn, 42, and 84. The following implants were used: placebo (0), Z (36 mg zeranol), ET (20 mg estradiol, 200 mg testosterone), EP/2 (10 mg estradiol, 100 mg progesterone), EP (20 mg estradiol, 200 mg progesterone), and EBA (24 mg estradiol, 120 mg trenbolone acetate). The following sequences were compared: 0-0-0 (negative control), 0-ET-ET, Z-ET-ET, 0-EP-EP, Z-EP-EP, 0-EP/2-EBA, and Z-0-EBA. From 0 to 42 d, Z implants increased (P<.05) ADG by 3.4% compared to placebo. However, implant schemes without an initial Z implant (0-ET-ET and 0-EP-EP) had higher (P<.05) mean ADG for the period from d 42 to 84. From 84 d to the end of the experiment, only the 0-EP/2-EBA treatment increased (P<.05) ADG compared to 0-0-0. Over the entire trial 0-ET-ET, 0-EP-EP, Z-EP-EP, and 0-EP/2-EBA implant sequences increased (P<.05) ADG by 3.2, 3.2, 2.4, and 4.7%, respectively, compared to the 0-0-0 sequence. Blood traits measured within 2 wk before slaughter were not affected by implant sequence, except that sequences with EP had higher (P<.05) leukocyte counts than were observed for the other sequences. Testicular weight was less (P<.01) for all of the implant sequences than for the negative control and less (P<.05) for Z-ET-ET than for 0-ET-ET, 0-EP-EP, 0-EP/2-EBA, and Z-0-EBA. The type and frequency of medical treatments did not differ among implant sequences for any of the 42-d phases, or over the entire trial. Generally, the growth promotant implants currently approved for beef cattle resulted in approximately 50% of the increase in growth rate in Holstein intact bull calves, as has been observed in beef-type steers or heifers.

Sex steroids and odorants modulate gonadotropin-releasing hormone secretion in primary cultures of human olfactory cells

Olfactory neurons and GnRH neurons share a common origin during development. In the nasal epithelia, GnRH neurons persist throughout fetal life and adulthood. The fate and function of these neurons in vivo have remained unknown. In a previous in vitro study, we isolated, cloned, and propagated primary long term cell cultures from the olfactory neuroepithelium of 8- to 12-week-old human fetuses. These cells expressed both neural proteins as well as olfactory genes and were responsive to odorant stimuli. We now report that these human olfactory cells also express the GnRH gene and protein. Combined HPLC and RIA studies have indicated that these cells release authentic GnRH in spent media. The release of GnRH was time dependent and was positively affected by sex steroids and odorants. Immunohistochemical data demonstrated the presence of sex steroid receptors in these cells. The presence of the alpha- and beta-subtypes of the estrogen receptor was also demonstrated by RT-PCR and Western blot analysis. When the cells were stimulated with increasing concentrations of 17beta-estradiol in the presence of a fixed concentration of progesterone (10(-7) mol/L), the combination of the two steroids induced a 3- to 4-fold increase in GnRH secretion. This stimulatory effect was completely blunted by tamoxifen. Neither 17beta-estradiol nor progesterone was effective when tested separately. Treatment with increasing concentrations of the odorant, l-carvone, induced a time- and dose-dependent dramatic increase in GnRH protein release (1000-fold increase) and gene expression. Repeated application of the stimulus resulted in a progressive lower responsiveness of the cells. To our knowledge, this is the first time that primary cell cultures from human fetal olfactory neuroepithelium have been shown to express and release GnRH. Our results also demonstrate that these cultures, which are sensitive to sex steroids and odorants, can be useful models in the study of the complex array of regulatory factors that finely tune GnRH secretion in humans.

Administration of progesterone to cows with ovarian follicular cysts results in a reduction in mean LH and LH pulse frequency and initiates ovulatory follicular growth

Cows with ovarian follicular cysts were treated with progesterone to determine whether a reduction in LH concentrations and initiation of ovulatory follicular waves would occur. Cysts were diagnosed using transrectal ultrasonography when single follicular structures > 20 mm or multiple structures > 15 mm in diameter were present for 7 d in the presence of low progesterone concentrations. Three groups were studied: 1) cows with normal estrous cycles (CYC, n = 8); 2) cows with untreated cysts (CYST, n = 7); and 3) cows with cysts treated with two progesterone-releasing intravaginal devices (PRID, n = 8) for 9 d. Ovaries were examined with transrectal ultrasonography, and blood samples were collected daily for analysis of progesterone and FSH. Serial blood samples for determination of mean LH and LH pulse frequency were collected on d 0 (CYST and PRID cows only), 1, 5, 9, and 10. Progesterone concentrations were higher in PRID cows than in CYST cows throughout the PRID treatment period (P < .002). On d 0, LH pulse frequency was similar (P = .10) in PRID (6.6+/-.6 pulses/8 h) and CYST cows (5.1+/-.6 pulses/8 h), but mean LH tended to be higher (P = .054) on d 0 in PRID cows (2.5+/-.2 ng/mL) than in CYST cows (1.9+/-.2 ng/mL). Mean LH and LH pulse frequency decreased (P < .002) by d 1 in PRID cows (1.1+/-.2 ng/mL, 1.8+/-.6 pulses/8 h) compared with CYST cows (2.1+/-.2 ng/mL, 5.6+/-.6 pulses/8 h) and remained lower throughout most of the experimental period. The FSH concentrations were higher (P < .01) in PRID cows than in CYC and CYST cows on d 3 and 4. The increase in FSH concentrations preceded emergence of the PRID-induced follicular wave. All PRID cows and four of seven CYST cows initiated new follicular waves during the period of PRID treatment. Follicular waves were initiated later (P < .05) in CYST cows (d 5.2+/-1.7) and PRID cows (d 5.5+/-.6) than in CYC cows (d 1.8+/-.3). Cysts were smaller (P < .01) at the end of the treatment period in PRID cows compared with CYST cows. No CYST cows ovulated, but all PRID cows ovulated newly developed follicles 3 or 4 d after PRID removal. Treatment with exogenous progesterone reduced LH in cows with cysts, and this was followed by development of normal ovulatory follicles.