Role of estrogen and prolactin in stimulation of carcinogen-induced mammary tumor development by a high-fat diet.

The role of estrogen and prolactin in high-fat (HF) dietary stimulation of carcinogen-induced mammary tumors was examined in female Sprague-Dawley rats. At 55 days of age, the rats were given injections i.v. of 5 mg of dimethylbenz(a)anthracene and, 5 days later, rats were sham- or bilaterally ovariectomized. Ten days after dimethylbenz(a)anthracene administration, the rats were placed on either a 20.0% HF diet or a 4.5% control fat (CF) diet and were then subjected to various drug and endocrine treatments to maintain uniform levels of circulating estrogen and prolactin. Sham-operated intact rats and bilaterally ovariectomized rats were given daily injections of haloperidol to increase prolactin secretion, bromocryptine to decrease prolactin secretion, and/or estradiol benzoate (EB). The intact rats fed the HF diet showed significant stimulation of all parameters of mammary tumor development when compared to similarly treated rats fed the CF diet. In ovariectomized rats fed either the HF or CF diet, there was nearly complete inhibition of mammary tumor development. When the HF diet was given to ovariectomized rats treated daily with either haloperidol or EB, or EB and bromocryptine, some parameters of mammary tumor development were enhanced by the HF diet. However, in all cases, mammary tumorigenesis was reduced when compared to sham-operated control rats. Ovariectomized rats fed the HF diet and given both EB and haloperidol exhibited significantly greater tumor number per rat, increased average tumor size, and reduced tumor latency period when compared to similarly treated rats fed the CF diet. However, these parameters of mammary tumorigenesis were still reduced when compared to those of sham-control rats fed the HF diet. These results indicate that a HF diet requires adequate circulating levels of estrogen and prolactin to maximally promote increased mammary tumorigenesis in dimethylbenz(a)anthracene-treated rats. Moreover, the enhancing effects of a HF diet on mammary tumorigenesis can be achieved in the presence of similar circulating levels of estrogen and/or prolactin, whether decreased or increased. These results suggest, therefore, that mechanisms independent of altered secretion of estrogens and/or prolactin are involved in promotion of mammary tumorigenesis by high levels of dietary fat.

Influence of underfeeding during the "critical period" or thereafter on carcinogen-induced mammary tumors in rats.

Normal cycling virgin female Sprague-Dawley rats were divided into different treatment groups and subjected to half ad libitum feed intake for 2 or 4 weeks at consecutive periods of time before and/or after administration of 7,12-dimethylbenz(a)anthracene (DMBA) and then were returned to full-feed. All rats at the end of their respective under-feeding periods showed reductions in serum prolactin and cessation of estrous cycles. However, only rats underfed 1 week prior to and 1 week after DMBA administration showed significant reductions in mammary tumorigenesis or the entire 21 weeks of the experiment when compared to full-feed controls. Rat groups underfed during subsequent weeks after DMBA administration showed no alterations in mammary tumor development as compared to full-fed controls. These results demonstrate that inhibition and perhaps permanent suppression of mammary tumorigenesis occurred only in rats underfed 1 week before and 1 week after DMBA administration. The inhibitory effects produced by this under-feeding regimen on mammary tumorigenesis may be mediated by suppression of prolactin and estrogen secretion.

Effects of alterations in early hormonal environment on development and hormone dependency of carcinogen-induced mammary tumors in rats.

The purpose of this study was to determine the early role of estrogen and prolactin on subsequent hormone dependency of carcinogen-induced mammary tumors. Virgin 57-day-old Sprague-Dawley rats were given i.v. injections of 7,12-dimethylbenz(a)anthracene (DMBA). One day prior to and 7 days after DMBA administration, the rats were divided into separate groups and given: a daily 0.1-ml s.c. injection of vehicle (controls); haloperidol (0.5 mg/kg) to increase prolactin secretion; estradiol benzoate (1 microgram/rat) to increase estrogen levels; bromocryptine (5 mg/kg) to inhibit prolactin release; tamoxifen (TAM, 20 micrograms/rat) to inhibit estrogen action; or the combination of TAM and bromocryptine. Drug and hormone treatments were terminated after 8 days. Sixteen weeks after DMBA administration, all animals were bilaterally ovariectomized, and 4 weeks later it was determined whether the mammary tumors were hormone dependent or independent. Treatment with TAM resulted in a significant reduction in incidence of mammary tumors, but also a 3-fold increase in the percentage of these tumors that showed hormone independence after ovariectomy as compared with that of control rats. Rats treated with the combination of TAM and bromocryptine also showed a significant reduction in tumor incidence and number, but a 5-fold greater percentage of hormone-independent tumors after ovariectomy. Rats given daily injections of haloperidol or estradiol benzoate showed only small differences in mammary tumor incidence or autonomy after ovariectomy, as compared with controls given injection vehicle alone. These results suggest that rats made deficient in estrogen and prolactin at the time of DMBA administration develop fewer tumors, but the tumors that develop are not dependent on these hormones for subsequent growth.

Reduced frequency of pulsatile luteinizing hormone secretion in the luteal phase of the rhesus monkey. Involvement of endogenous opiates.

Pulsatile secretion of LH in women has been shown to vary during the menstrual cycle. LH pulse frequency during the luteal phase is markedly reduced compared to that in the follicular phase. The objectives of the present study were to determine if similar changes in pulsatile LH secretion occur in the monkey, and whether endogenous opiates are involved in producing these changes. In order to document if LH pulse frequency is reduced in the nonhuman primate luteal phase, serial blood samples were collected from 10 rhesus monkeys at 15-min intervals for 6 h at 3 different times of the luteal phase (early, mid-, and late). This pattern of secretion was contrasted to that observed during the ensuing early follicular phase. LH pulse frequency during the luteal phase was significantly reduced compared to the early follicular phase. Mean pulse frequency (+/- SE) was 0.84 +/- 0.16 pulses/6 h in the luteal phase vs. 2.99 +/- 0.58 pulses/6 h in the early follicular phase. When endogenous opioid activity was blocked during the luteal phase by a 5-h continuous infusion of naloxone (2 mg/h), an opiate antagonist, LH pulse frequency was increased to 2.48 +/- 0.25 pulses/5 h. This frequency was markedly different from the frequency of 0.85 +/- 0.17 pulses/5 h observed in the control period which immediately preceeded the naloxone infusion. The mean amplitude of the LH pulses in the luteal phase, which was significantly greater than that observed in the early follicular phase (20.9 +/- 1.9 ng/ml and 11.7 +/- 0.3 ng/ml) was not affected by naloxone (23.5 +/- 2.4 ng/ml vs. 25.3 +/- 1.9 ng/ml). Infusion of naloxone for longer periods (9 h) in 3 additional monkeys caused an increase in LH pulse frequency which was maintained in 2 of the monkeys, whereas the third animal exhibited only an acute response (a single pulse). These results indicate that the reduction in LH pulse frequency that occurs in the luteal phase of the rhesus menstrual cycle is an event in which endogenous opiates participate. Our previous finding that beta-endorphin release from neurons in the median eminence is stimulated during the luteal phase of the monkey, together with the present results, suggest that beta-endorphin functions as a modulator of pulsatile LH secretion in the primate menstrual cycle.

Gonadotropin-releasing hormone pulses in third ventricular cerebrospinal fluid of ovariectomized rhesus monkeys: correlation with luteinizing hormone pulses.

Morphological evidence suggests that GnRH may be released into cerebrospinal fluid (CSF) of the third ventricle. Therefore, a method of cannulating the third ventricle of monkey brains was developed for the purpose of examining GnRH secretion in primates. A stainless steel guide cannula was stereotaxically implanted into the third ventricle of 14 ovariectomized rhesus monkeys. A Silastic cannula for collecting CSF was inserted via the guide cannula into the ventral portion of the ventricle, permitting repeated CSF sampling for long time periods from the same animal. One week to 6 months after cannulation, CSF was collected continuously for periods of 5-10 h at 2 different rates (480 and 120 microliter/h) from conscious monkeys seated in chairs. Samples were divided into 15-min fractions, and the GnRH concentration in each was determined by RIA. In contrast to most previous studies, third ventricular CSF was found to contain significant concentrations of GnRH. GnRH was detected in 40 of 50 collections. Concentrations ranged from less than 8 to greater than 800 pg/ml, a range similar to that observed in hypophyseal portal blood. Furthermore, fluctuations within individual collections indicated that GnRH was released in pulses. The mean GnRH pulse frequency during the higher rate of CSF withdrawal was 0.43 +/- 0.06 pulses/h (n = 31), while the mean pulse amplitude was 91 +/- 7 pg/ml (n = 64). Neither parameter was influenced by the rate of CSF removal, as frequency was 0.52 +/- 0.08 pulses/h (n = 19) and amplitude was 94 +/- 11 pg/ml (n = 82) during the lower collection rate. However, the CSF withdrawal rate had a profound influence on LH secretion. In 12 of 17 collections at the higher rate, LH levels plummeted to undetectable concentrations during the first 2 h of CSF exfusion and remained low throughout the collection period. Pituitary responsiveness was not reduced, as a GnRH bolus (0.25 or 2.5 micrograms) after 6 h of CSF removal elicited a dose-dependent stimulation of LH secretion. In contrast, a higher incidence of normal pulsatile LH secretion (12 of 19 collections) was observed when the CSF withdrawal rate was reduced. During these 12 collections, LH and GnRH pulses occurred at regular intervals and exhibited similar pulse frequencies (mean +/- SE, 0.76 +/- 0.07 and 0.67 +/- 0.09 pulses/h for LH and GnRH, respectively). Most GnRH and LH pulses were synchronized, as 86% of all GnRH pulses (43 of 50) were accompanied by a LH pulse.(ABSTRACT TRUNCATED AT 400 WORDS)

Naloxone stimulation of luteinizing hormone secretion in the female monkey: influence of endocrine and experimental conditions.

It is known that opiate administration results in the inhibition of LH release. In this paper, we examine the role of endogenous opiates in the regulation of gonadotropin secretion during the menstrual cycle of the monkey. The objectives of these experiments were to determine the experimental and endocrine conditions that are conducive to increased gonadotropin secretion in response to endogenous opiate antagonism. In Exp 1, naloxone was administered during the luteal phase to three groups of monkeys under three different experimental conditions. When naloxone (2 mg, iv) was injected into conscious unrestrained or sedated animals, LH secretion increased 2- to 3-fold. In contrast, the same dose of naloxone failed to stimulate LH secretion in monkeys restrained in primate chairs. In Exp 2, the gonadotropin response to acute naloxone administration on each day of the menstrual cycle was determined. A significant increase in the serum LH concentration (greater than or equal to 20% within 40 min of injection) was observed after naloxone administration in 60% of the trials conducted during the luteal phase. Significant increases occurred in only 13% of the saline-treated control trials during this stage of the menstrual cycle. Mean LH levels increased from 14.4 +/- 1.3 to 31.2 +/- 4.3 ng/ml after naloxone injection. In contrast, naloxone had no effect on LH secretion during the follicular phase. Although small LH increments were noted after naloxone injection in 40 +/- 8% of the trials, neither the frequency nor the amplitude of these increases was different from that in follicular phase controls. We conclude from these results that the ability of naloxone to stimulate LH secretion is limited to the luteal phase. Previous findings from our laboratory indicate that hypothalamic beta-endorphin activity, as reflected by its concentration in hypophyseal portal blood, is increased by ovarian steroids and that its greatest activity occurs during the luteal phase. Since the response of LH to naloxone administration was limited to the luteal phase, we believe that these results support the conclusion that hypothalamic beta-endorphin is a physiological modulator of LH secretion in the monkey.

The effects of estrogen and progesterone on corticotropin-releasing hormone and arginine vasopressin messenger ribonucleic acid levels in the paraventricular nucleus and supraoptic nucleus of the rhesus monkey.

Ovarian steroids increase hypothalamic-pituitary-adrenal (HPA) axis activity and sensitize the hypothalamic-pituitary-ovarian (HPO) axis to stress-induced inhibition. The present study investigated the effect of ovarian steroids on CRH and arginine vasopressin (AVP) messenger RNA (mRNA) levels in the rhesus monkey hypothalamus, as both neuropeptides have been shown to stimulate the HPA axis and inhibit the HPO axis in this species. This was accomplished by measuring CRH and AVP mRNA in the paraventricular nucleus (PVN) and supraoptic nucleus (SON) by in situ hybridization histochemistry. Menstrual cycles were simulated in ovariectomized (OVX) rhesus monkeys by sequential addition and removal of SILASTIC brand (Dow Corning Corp.) tubing containing either 17beta-estradiol (E2) or progesterone (P4). On the morning of day 11 of the simulated follicular phase (E2 alone) or day 21 of the luteal phase (E2 + P4), animals were anesthetized, and the brains were perfused with paraformaldehyde via the carotid artery. Coronal sections (30 microm) were cut, and mRNA for CRH and AVP in the paraventricular nucleus (PVN) and supraoptic nucleus (SON) were semiquantified by in situ hybridization. CRH mRNA in the PVN of E2-replaced OVX animals (n = 7) was 2-fold greater than that in untreated OVX controls (n = 4), whereas CRH mRNA after E2 + P4 (n = 4) was no different from that in controls (optical density + SEM, 0.38 +/- 0.06, 0.13 +/- 0.08, and 0.14 +/- 0.09 for OVX + E2, OVX + E2 + P4, and OVX, respectively; P = 0.02). CRH in the SON was undetectable. In contrast to CRH, AVP mRNA in the PVN and the SON was similar in the three treatment groups. We conclude that E2 and E2 + P4 replacement to OVX monkeys exert different effects on CRH and AVP gene expression, as estrogen stimulation of CRH mRNA in the PVN was abrogated by progesterone, whereas no effect of ovarian steroids on AVP mRNA in either the PVN or SON was observed. We postulate that ovarian steroid regulation of CRH synthesis and release may in part explain the central nervous system mechanisms by which ovarian steroids affect the HPA and HPO axes during basal and stress conditions.

Luteinizing hormone secretion and corticotropin-releasing factor gene expression in the paraventricular nucleus of rhesus monkeys following cortisol synthesis inhibition.

Corticotropin-releasing Factor (CRF) is an important inhibitory neuromodulator of GnRH/LH secretion, and mediates in part the inhibitory effects of stress on the hypothalamic-pituitary-gonadal axis. The purpose of the present study was to further investigate CRF's role in regulating LH secretion in primates. This was accomplished by examining LH secretion in ovariectomized rhesus monkeys (n = 7) following cortisol synthesis inhibition with metyrapone. Infusion of metyrapone (5 mg/kg per h) for 4 h decreased cortisol levels to less than 20% of controls while increasing ACTH approximately 10-fold. LH concentrations were not affected by this acute activation of the hypothalamic-corticotroph axis. In a second experiment, metyrapone was infused for 10 h before collecting serial blood samples every 15 min for 6 h. Although this protocol produced a sustained increase in ACTH, no apparent effect on pulsatile LH secretion compared with saline controls was observed. Mean LH (+/- SEM) levels calculated for consecutive 2-h increments were 87.6 +/- 9.2 (0-2 h) 82.1 +/- 5.5 (2-4 h), and 80.7 +/- 4.8 (4-6 h) ng/ml in saline pretreated animals compared with 83.6 +/- 4.9, 79.8 +/- 5.8, and 72.5 +/- 6.2 ng/ml, respectively, in metyrapone pretreated monkeys. The same regimen of metyrapone infusion increased CRF messenger RNA levels in the paraventricular nucleus by approximately 33% (P < 0.0002). In a final experiment designed to examine the potential synergy between CRF and cortisol, the LH response to insulin-induced hypoglycemia was contrasted in saline and metyrapone pretreated monkeys. LH concentrations were reduced to approximately 40% of basal levels following insulin in both metyrapone and saline pretreated monkeys. Therefore, even though inhibition of cortisol synthesis leads to an increase in CRF messenger RNA in the paraventricular nucleus and a robust increase in ACTH secretion in rhesus monkeys, presumably due in part to increased neuroendocrine CRF secretion, LH secretion was not inhibited during either the acute or more chronic phase of corticotroph activation. Absence of LH inhibition was not due to low cortisol concentrations resulting from metyrapone because metyrapone did not prevent hypoglycemia-induced suppression of LH secretion. We conclude that increased neuroendocrine CRF secretion following metyrapone does not inhibit LH secretion under these conditions. Several explanations for this result are discussed.

Comparison of acute effects of dynorphin and beta-endorphin on prolactin release in the rat.

The ability of dynorphin and beta h-endorphin (beta h-EP) to stimulate prolactin (PRL) release in male rats was examined. Rats were injected intraventricularly with either 1 or 10 microgram dynorphin, 1 or 10 microgram beta h-EP, 10 microgram dynorphin together with 20 microgram naloxone (NAL), or an equivalent volume (13 microliter) of saline. Dynorphin caused a dose-dependent release of PRL which was significant 10 min after injection but not at later sampling times. beta h-EP also increased serum PRL levels and maintained elevated PRL levels for at least 60 min. NAL, a specific opiate antagonist, completely blocked dynorphin-induced PRL release. These results indicate that dynorphin is a potent stimulator of PRL release, but its stimulatory activity is transient relative to the activity exhibited by beta h-EP. Furthermore, dynorphin's action is specific since NAL completely blocked dynorphin induced PRL release.

Progesterone inhibits the estrogen-induced gonadotropin surge in the rhesus monkey independent of endogenous opiates.

Administration of an estrogen challenge during the luteal phase, a time when progesterone concentrations are elevated, fails to elicit a gonadotropin-positive feedback response. The purpose of the present study was to determine if endogenous opiates are involved in the mechanism by which progesterone blocks the estrogen-induced gonadotropin surge in monkeys. To this end, rhesus monkeys in the luteal phase were pretreated with either saline or various regimens of nalmefene, a long-acting opiate antagonist, before being given an estrogen challenge. Three groups of animals were given nalmefene (10 mg, iv) every 12 h beginning 24, 48, or 96 h before an estrogen challenge and continued until 48 h after the start of the estrogen challenge. A fourth group received a continuous sc infusion of nalmefene (20 mg/day) via osmotic minipumps beginning 48 h in advance of the estrogen challenge. In a second experiment, monkeys in the follicular phase received progesterone implants at the time of an estrogen challenge and iv injections of nalmefene every 12 h for 48 h. Gonadotropin and steroid levels were monitored in both experiments by collecting blood samples by saphenous venipuncture at intervals of 6-12 h. The majority of luteal phase animals that were pretreated with saline were unresponsive to the estrogen challenge. Only 2 of 16 (12.5%) had an increase in LH concentrations that could be classified as a surge. Animals pretreated with iv nalmefene every 12 h beginning 48 h before the estrogen challenge exhibited a higher incidence of positive feedback responses (8 of 12 or 66.7%). A concomitant FSH surge was observed in 3 of these instances. However, when progesterone concentrations, which declined before the estrogen challenge in the nalmefene-treated group, were supplemented with exogenous progesterone, nalmefene failed to evoke any LH surges. Six of 8 animals that received nalmefene by sc infusion exhibited LH responses. However, the amplitude and duration of these LH responses were diminished, and no FSH responses were observed. Monkeys pretreated with nalmefene for either shorter (24 h) or longer (96 h) periods before the challenge were less responsive (0 responses out of 6 trials and 1 response out of 4 trials, respectively). Nalmefene was equally ineffective in preventing progesterone inhibition of the estradiol-induced LH surge in follicular phase animals (0 of 15 animals had LH surge). These results indicate that nalmefene antagonism of endogenous opiates does not enable estrogen to exert positive feedback effects on LH release when progesterone levels are high, such as during the luteal phase or after progesterone administration.(ABSTRACT TRUNCATED AT 400 WORDS)

Adrenocorticotropin immunoactivity in monkey hypophyseal portal blood.

ACTH was measured with both C-terminal and midportion antibodies in monkey hypophyseal portal plasma, and compared to levels in monkey peripheral plasma, medial basal hypothalamus, and anterior pituitary. In nine female monkeys, mean hypophyseal portal blood C-terminal ACTH immunoactivity was 5290 +/- 2010 (SEM) pg/ml, whereas the mean midportion ACTH level was 949 +/- 178 pg/ml. These immunoactivities were not lower in two monkeys that were completely hypophysectomized 30 min before portal blood collection. The ratio of C-terminal to midportion ACTH immunoactivity was 4:1 in two monkey medial basal hypothalami, and 1:1 in four monkey anterior pituitary glands. Gel filtration of hypophyseal portal plasma extract and of medial basal hypothalamus showed that the C-terminal ACTH immunoactivity eluted in the same position as the corticotropin-like-intermediate lobe peptide standard. The similarity of the C-terminal to midportion ACTH ratios in monkey medial basal hypothalamus and portal blood, and the observation that ACTH immunoactivity was not significantly lower in two hypophysectomized monkeys suggests that portal blood C-terminal ACTH immunoactivity is of hypothalamic rather than pituitary origin. We conclude that monkey hypophyseal portal blood contains high levels of a C-terminal fragment of ACTH, which coelutes with corticotropin-like intermediate lobe peptide on gel filtration, and which is secreted from the brain directly into the portal circulation.

Hypoglycemia-induced inhibition of luteinizing hormone secretion in the rhesus monkey is not mediated by endogenous opioid peptides.

A role for endogenous opioid peptides in stress-induced inhibition of LH secretion has been suggested based on the observation in rats, humans, and nonhuman primates that LH inhibition in response to a variety of different stresses could be blocked by the administration of opiate antagonists. In the present study, we have examined in rhesus monkeys whether suppression of LH secretion by insulin-induced hypoglycemia is prevented by administration of the opiate antagonist naloxone. The administration of 1.0 U insulin/kg to chair-restrained ovariectomized monkeys (n = 6) decreased blood glucose levels from 4.98 +/- 0.17 to 2.08 +/- 0.05 mmol/L and increased cortisol levels from 1279 +/- 205 to 2191 +/- 475 nmol/L. LH levels declined to 62% of the levels observed in the pretreatment control period (P < 0.05). Infusion of naloxone (2-mg bolus plus 2 mg/h or 10-mg bolus plus 10 mg/h) did not reverse the effects of insulin-induced hypoglycemia on LH concentrations. The administration of 1.0 U insulin/kg to nonrestrained monkeys produced a similar hypoglycemic state. Blood glucose levels declined from 4.08 +/- 0.11 to 2.45 +/- 0.05 mmol/L, while cortisol concentrations increased from 577 +/- 53 to 1324 +/- 294 mmol/L. However, LH concentrations did not decline in response to hypoglycemia. These data indicate that hypoglycemia-induced inhibition of LH secretion in chair-restrained ovariectomized monkeys is not mediated by endogenous opiates, since naloxone failed to reverse this effect. The observation that hypoglycemia inhibited LH levels only during a period of restraint suggests either an additive or synergistic effect of these two stresses on LH secretion.

Immunoreactive beta-endorphin in the plasma, pituitary and hypothalamus of young and old male rats.

Immunoreactive beta-endorphin (IR-beta-ENDO) was measured in the plasma, pituitary, and hypothalamus of young (3-5 mo.) and old (19-23 mo.) male Sprague-Dawley rats, using a specific radioimmunoassay. Plasma IR-beta-ENDO in old male rats (3.44 +/- 0.54 ng/ml) was more than three times higher than values observed in young male rats (1.00 +/- 0.10 ng/ml). Pituitary content and concentration of IR-beta-ENDO also were significantly greater in the old (5.85 +/- 0.51 microgram/gland and 1.17 +/- 0.10 microgram/mg protein) than in the young (3.53 +/- 0.29 microgram/gland and 0.78 +/- 0.06 microgram/mg protein) male rats. The content of IR-beta-ENDO in the hypothalamus of old and young rats was nearly the same (43.45 +/- 2.47 and 49.88 +/- 6.35 ng/hypothalamus, respectively), whereas the concentration of IR-beta-ENDO in the hypothalamus of the old male rats (3.89 +/- 0.25 ng/mg protein) was approximately 50% lower than that observed in the young male rats (7,80 +/- 0.85 ng/mg protein). These changes in plasma, pituitary, and hypothalamic IR-beta-ENDO may contribute to the increase in prolactin and decrease in gonadotropins observed in old male rats, since beta-ENDO administration is known to produce these effects on prolactin and gonadotropin secretion.

A randomized, placebo-controlled, crossover trial of danazol for the treatment of premenstrual syndrome.

To investigate whether danazol is more effective than placebo for the treatment of premenstrual syndrome (PMS), we conducted a randomized, double-blind, crossover study comparing three successive cycles of danazol (200 mg bid) to three cycles of placebo. Thirty-one women meeting rigorous criteria for a diagnosis of severe PMS over two pretreatment cycles were enrolled; 28 of these subjects completed at least one cycle of treatment with symptom recordings, which were entered into the analysis. A significant period effect confounded the planned within-subject analysis and therefore, the main treatment comparisons were confined to the first period only. Symptom scores on the Premenstrual Tension Self-Rating Scale (PMTS), Beck Depression Inventory (BDI), and a Visual Analogue Scale (VAS) were compared for the premenstrual week in the last cycle of treatment. For the 16 patients on danazol, scores on the PMTS decreased by an average of 14.0 (10.7) (standard deviation) points from a baseline of 25.4 (5.6) points. For the 12 patients on placebo, PMTS scores decreased by an average of 3.6 (9.5) points from a baseline of 23.5 (5.8) points (14.0 vs. 3.6; p = .0133, unpaired t-test). Seven (43.8%) of the subjects on danazol achieved a clinically relevant reduction of symptoms into the asymptomatic range (PMTS scores < or = 5) as compared to one (8.3%) of the subjects on placebo. Thus, danazol (200 mg bid) provided greater relief from severe PMS during the premenstrual week than did placebo.

Development of a national course on research methodology for Canadian residents in obstetrics and gynecology.

OBJECTIVE: To report our experience developing and implementing an introductory course on research methods for Canadian obstetrics and gynecology residents. METHODS: A program entitled "An Introduction to Research," originating at Queen's University, developed into an annual series of regional courses across Canada, under the auspices of the Association of Professors of Obstetrics and Gynaecology of Canada. Didactic lectures, interactive workshops, and online computer demonstrations introduced participants to the basic elements of clinical research. RESULTS: Since its inception, over 1000 participants have attended the program. Nearly all of the 296 respondents to a course evaluation agreed that the program was well organized, presented material at an appropriate level, and was useful. CONCLUSION: This course ensured that residents in obstetrics and gynecology across Canada were given a basic level of research training, as required by the Royal College of Physicians and Surgeons of Canada.

A randomized, double-blind, placebo-controlled, cross-over trial to assess the side effects of medroxyprogesterone acetate in hormone replacement therapy.

Cyclic progestin therapy has been widely advocated as an adjunct to postmenopausal estrogen replacement therapy to reduce the risk of endometrial carcinoma. Acceptance of this approach, however, appears to have preceded detailed evaluation of possible adverse side effects of progestins that could result in patient noncompliance. We evaluated the nonmenstrual physical and psychological side effects of oral medroxyprogesterone acetate given in conjunction with transdermal estrogen in two groups of women with previous hysterectomy and oophorectomy. Twenty-four women with prospectively documented severe premenstrual syndrome (PMS) before surgery and 24 women with no such history of adverse premenstrual changes received transdermal estrogen 100 micrograms on days 1-25 and either oral medroxyprogesterone acetate 10 mg daily or an identical placebo (days 12-25) in a randomized, double-blind, cross-over design. Mood and physical symptoms were monitored prospectively, using daily self-ratings on the Daily Symptoms Checklist. The Beck Depression Inventory and Premenstrual Tension Self-Rating Scale were completed on day 24. At the study's completion, the patients were asked which treatment period they preferred. Paired comparisons did not reveal any significant differences, and preference for treatment was equally divided between medroxyprogesterone acetate and placebo. We conclude that addition of medroxyprogesterone acetate 10 mg/day for 14 days to cyclic transdermal estrogen therapy (days 1-25) produces no consistent adverse physical or psychological effects on women for one cycle of treatment, regardless of their PMS history.

The effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin on corticotrophin-releasing hormone, arginine vasopressin, and pro-opiomelanocortin mRNA levels in the hypothalamus of the cynomolgus monkey.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a widespread environmental contaminant that has profound deleterious effects on development and reproduction. TCDD may act at one or more levels to alter the hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-gonadal (HPG) axes. The objective of this study was to investigate whether TCDD modulates neuroendocrine systems by altering gene expression of arginine vasopressin (AVP), corticotrophin-releasing hormone (CRH), or pro-opiomelanocortin (POMC), which are important neuroregulators of the HPA and HPG axes. Four groups of female cynomolgus monkeys (Macaca fascicularis) were administered daily oral doses of gelatin capsule containing TCDD (0, 1, 5, or 25 ng/kg body weight) mixed with glucose 5 days a week for 1 year. At the end of the dosing period, animals were euthanized and brains were harvested. CRH, AVP, and POMC mRNA levels were semiquantified by in situ hybridization histochemistry on 30-microm coronal sections of the brain. Blood collected on the day of euthanasia was assayed for cortisol and progesterone. CRH mRNA levels in the paraventricular nucleus (PVN) were significantly increased by the 2 higher TCDD doses (5 and 25 ng/kg/day) compared to controls (p < 0.05). There was a trend towards increased AVP mRNA levels in both the supraoptic nucleus (SON) and PVN. No effect of TCDD on POMC was observed. Cortisol levels were significantly increased in TCDD-exposed animals. Progesterone concentrations and menstruation data indicated that TCDD did not interfere with ovulation. We conclude that TCDD stimulated the HPA axis by a central effect involving CRH, but had no effect on the HPG axis at the doses tested.

Subfornical organ activation stimulates luteinizing hormone secretion in the rat.

The effect of electrical stimulation in the subfornical organ (SFO) on plasma luteinizing hormone (LH) concentrations has been examined in the conscious freely moving male Sprague-Dawley rat. Plasma LH levels were significantly elevated above basal levels 15 min following stimulation in the SFO. In contrast, stimulation in the adjacent hippocampal commissure caused no significant change in plasma concentrations of LH. These results correlate well with previous electrophysiological studies demonstrating that SFO stimulation activates putative LH-releasing hormone (LH-RH) containing neurons in the septum which project to the median eminence and add further support to the hypothesis that the SFO plays a significant role in the control of reproductive function.

The stability of synthetic gonadotropin-releasing hormone in solution.

The stability of GnRH stored in solution under different conditions was assessed employing both immunoassay and bioassay techniques. No appreciable loss of activity was encountered after 4 weeks of storage at either 4 degrees C or room temperature.

Photodynamic ablation of early pregnancy in the rat with 5-aminolevulinic acid: a potential new therapy for tubal ectopic pregnancy in the human.

OBJECTIVE: To determine whether systemic 5-aminolevulinic acid (ALA) could produce photosensitization and photodynamic ablation of early pregnancy in the rat. SETTING: A conventional laboratory setting. PATIENTS: Female Sprague-Dawley rats, weighing 220 to 275 g at the time of breeding. INTERVENTIONS: Rats at 10 days of gestation were injected IV with saline, 20 or 200 mg/kg ALA. Three hours later, the abdominal cavity was opened to record the number of fetuses in both uterine horns. One or both uterine horns were exposed to photoactivating light at 630 nm for 0, 5, 15, or 30 minutes. MAIN OUTCOME MEASURES: Mean fetal survival rate was determined 7 days after treatment. RESULTS: The mean +/- SEM fetal survival rates in groups (n = 6) treated with saline, 20 or 200 mg/kg ALA followed by 30-minute light exposure were 90.8% +/- 2.8%, 16.0% +/- 4.9%, and 0%, respectively. The mean +/- SEM fetal survival rates in groups (n = 6) treated with 200 mg/kg ALA followed by 0-, 5-, 15-, or 30-minute light exposure were 71.3% +/- 11.8%, 8.9% +/- 6.2%, 0.9% +/- 1.3%, and 0%, respectively. CONCLUSIONS: We conclude that systemic ALA followed by transmural exposure to photoactivating light (630 nm) results in resorption of early pregnancies in the rat. This approach could potentially be developed as a new treatment for human ectopic pregnancy.