Suppression of the development of uterine adenomyosis by danazol treatment in mice.

Inhibitory effects of danazol, an isoxazol derivative of synthetic steroid 17 alpha-ethinyl-testosterone, on the development of uterine adenomyosis, a pathological disorder of endometrial tissue defined as the presence of endometrial glands and stroma in the myometrium, were investigated in mice of SHN strain. Mice treated with 0.5 microgram danazol for 5 weeks during 4-9 weeks of age and killed at 21 weeks of age showed significantly lower incidence of the spontaneous development of adenomyosis than the age-matched intact control mice. The inhibitory effects of danazol were also evident in mice bearing pituitary isografts which were effective in inducing an early and a high incidence of adenomyosis. Furthermore, the treatment with danazol resulted in the decrease of serum levels of luteinizing hormone (LH) and prolactin (PRL) associated with hypofunction of ovaries and persistent diestrus. These results support the usefulness of danazol for the clinical treatment of gynecological disorders except for hypofunction of ovaries.     

Increase of DNA synthesis in uterine adenomyosis in mice with ectopic pituitary isograft.

Ectopic pituitary isografts (EPI) have been found to induce a high incidence of uterine adenomyosis in SHN mice. All the SHN mice given EPI in the right uterus at 40 days of age developed uterine adenomyosis, and more than 80% of mice showed the genesis of subserosal nodules, an advanced state of adenomyosis, 65 days after EPI. Activities of both thymidylate synthetase and thymidine kinase, i.e. DNA-synthesizing enzymes in de novo and salvage pathways of pyrimidine metabolism, respectively, were significantly increased in EPI-induced uterine adenomyosis to approximately 2-fold those in normal control uteri. Bromodeoxyuridine-immunoreactive cells were regarded as the cells in S phase, and the number in the endometrial epithelium and stroma in EPI-induced uterine adenomyosis was more than 1.5-fold that in normal control uteri. EPI may affect the genesis of uterine adenomyosis generally, but not locally, because there were no differences between the right uterus with EPI and the left without EPI in the incidence of adenomyosis, histology or DNA-synthesizing enzyme activities.     

Development of uterine adenomyosis after treatment with dopamine antagonists in mice

Development of uterine adenomyosis was studied in SHN mice treated with psychotherapeutic drugs, sulpiride and perphenazine, and gastroenteric drug, metoclopramide, which act as dopamine antagonists to increase prolactin release from the pituitary gland. Administration of these drugs twice daily for 40-70 or 40-90 days of age induced an elevation in serum level of prolactin. Furthermore, the treated mice showed a prolongation of metestrous plus diestrous phase and a high incidence of uterine adenomyosis compared with vehicle-treated control mice. These results indicate that hyperprolactinemia produced by continuous treatment with psychotherapeutic and gastroenteric drugs is responsible for the occurrence of irregular estrous cycles and the genesis of uterine adenomyosis in mice.     

Effects of mifepristone (RU486) treatment on the development of uterine adenomyosis induced by pituitary grafting in mice

To evaluate the effects of mifepristone (RU486) on the development of uterine adenomyosis induced by pituitary grafting (PG), 3 groups of mice receiving pituitary grafts at 7 weeks of age were given RU486 in food (20 mg/kg chow) from 3-14 (RU486-3 group) or 10-14 (RU486-10 group) weeks of age, or were given no further treatment (PG control group), respectively. All the mice were killed at 14 weeks of age. The uterine weight was significantly decreased in both RU486-treated groups compared with the PG control group. The incidence of adenomyosis was also decreased significantly in both the RU486-3 group (0/10 mice) and RU486-10 group (2/10 mice) compared with the PG control group (7/9 mice). To look for vascular changes in the uterine tissues, which have been reported to be related to the development of adenomyosis, immunohistochemical staining of von Willebrand factor in the blood vessels was performed. The mean surface area and minor axis of blood vessels in the uterus were thereby found to be significantly decreased in the RU486-10 group compared to the PG control group. The results clearly indicated that RU486, a potent antiprogestin, could inhibit the genesis of uterine adenomyosis in mice, and at the same time caused shrinkage of the vascular system. As in humans, progesterone as well as the vascular system therefore appear to be important factors in the pathogenesis of uterine adenomyosis in this mouse model.     

Priming effects of novel nonsteroidal progesterone receptor modulators CP8816 and CP8863 on the development of adenomyosis in the mouse uterus

The possibility of therapeutic application of novel nonsteroidal progesterone receptor modulators CP8816 and CP8863 for preventing the development of uterine adenomyosis was investigated in mice. First priming effects of CP8816 on 17beta-estradiol (E2)-induced cell division in uterine tissues were examined. As a result, pretreatment with CP8816 or progesterone significantly suppressed the elevation of the mitotic activity in the luminal epithelial cells of mice treated with E2 later. Priming with CP8816 had little effect on the stromal cells, but progesterone priming caused an increase of stromal mitotic activity in mice treated with E2 later. To evaluate the inhibitory effect of these compounds on the development of adenomyosis induced experimentally by pituitary grafting, 7-week-old female mice were isografted with a single anterior pituitary in the uterus and divided into four groups. Two groups of mice were given daily subcutaneous injections of 1 mg of CP8816 or the vehicle alone for 6 weeks from the day after the grafting. Remaining two groups of mice were given oral administration of 1 mg of CP8863 or the vehicle only for 5 weeks starting one week after the grafting. The incidence of adenomyosis was significantly lower in the groups of mice treated with CP8816 and CP8863 than in the respective control groups. The mechanism by which CP compounds inhibited the development of adenomyosis might be related to their priming effects, i.e., their inhibitory effect on epithelial cell division and lack of effect on stromal cell division after subsequent exposure to E2.     

舒必利与垂体移植诱发小鼠子宫腺肌病的比较

目的比较舒必利诱导和垂体移植诱导两种造模方法的效果,评价适用于子宫腺肌病研究的小鼠模型。方法 45只7周龄未曾受孕的雌性BALB/c小鼠,随机分为对照组、舒必利组和垂体移植组,每组15只。舒必利组每日皮下注射舒必利,每20 g体重注射800μg,垂体移植组则将同种同龄雄鼠的垂体放入雌鼠右侧子宫内,对照组不予任何处理。5个月后以子宫湿重、终末体重、子宫湿重/终末体重的比值、卵巢湿重、子宫HE染色评分及模型成功率等指标评价造模效果。结果 5个月后舒必利组和垂体移植组小鼠的子宫湿重、子宫湿重/终末体重的比值、子宫HE染色评分及成功率均显著高于对照组,但两模型组各项指标比较差别无统计学意义,三组小鼠终末体重和卵巢湿重比较差别均无统计学意义。结论对照组无一例形成子宫腺肌病,舒必利诱导和垂体移植诱导两种造模方法均可引起小鼠子宫腺肌病,造模的各项评价指标均无显著差异,都可用于子宫腺肌病的研究。     

Suppression of the development of experimentally induced uterine adenomyosis by a novel matrix metalloproteinase inhibitor, ONO-4817, in mice

The inhibitory effects of a novel, orally active matrix metalloproteinase (MMP) inhibitor, ONO-4817, on the development of uterine adenomyosis induced experimentally by pituitary grafting were examined in mice. Mice were given transplants of isologous anterior pituitary glands (PGs) into the right uterine lumen at 7 weeks of age and were fed chow containing 0.1% to 1.0% ONO-4817 from 8 to 14 weeks of age. Mice treated with 0.3% or 1.0% ONO-4817 showed a significantly lower incidence of the development of adenomyosis than vehicle-treated mice. To evaluate the inhibitory effects of ONO-4817 on the progression of the invasion of the adenomyotic tissues, mice receiving PG grafts at 7 weeks of age were treated with 1.0% ONO-4817 from 13 to 17 weeks of age. The degree of pathological progression of adenomyosis was graded from 1 to 5 in increments of 1. The degree of the progression of the lesion was less in the uteri exposed to ONO-4817 (2.71 +/- 0.93) than in the uteri not exposed to the inhibitor (4.33 +/- 0.75). Finally, the invasiveness of endometrial stromal cells obtained from adenomyotic uteri into Matrigel consisting mainly of type IV collagen and laminin was examined using an invasion assay. The assay showed that the treatment with ONO-4817 markedly suppressed the invasion of the stromal cells of the adenomyotic uteri into the gel. These results indicate that ONO-4817 may be an effective inhibitor of the development of adenomyosis.     

Tumors induced by 1,2-dimethylhydrazine in hybrid mice with the pituitary gland transplanted in the kidney

1,2-Dimethylhydrazine (DMH) decreased the incidence of tumors in hypophyseal isografts in hybrid mice (CBA X C57BL/6)F1 and prevented the development of mammary tumors. In mice bearing hypophyseal isografts, there was a decrease in the incidence of DMH-induced hemangiomas of the ovary. The same mice showed no alterations in the incidence of DMH-induced uterine sarcomas, tumors of the large intestine, anal region and liver.     

Effects of treatment with prolactin or progesterone on the coincidence of mammary tumors and uterine adenomyosis in young SHN mice

The relative incidence of mammary tumors with uterine adenomyosis was examined in SHN mice subjected to hormonal manipulation between 30 and 90 days of age. The incidence of mammary tumors paralleled that of adenomyosis in controls. A single pituitary grafted under the kidney capsule or progesterone pellet implanted at a young age increased the incidence of both mammary and uterine lesions. However, the pattern of long-term response to hormones was different between mammary gland and uterus. The results indicate the possible relevance of this animal model for study of the cause and management of multiple endocrine syndrome in women.     

Regulation of prolactin in mice with altered hypothalamic melanocortin activity

This study used two mouse models with genetic manipulation of the melanocortin system to investigate prolactin regulation. Mice with overexpression of the melanocortin receptor (MC-R) agonist, α-melanocyte-stimulating hormone (Tg-MSH) or deletion of the MC-R antagonist agouti-related protein (AgRP KO) were studied. Male Tg-MSH mice had lower blood prolactin levels at baseline (2.9±0.3 vs. 4.7±0.7ng/ml) and after restraint stress (68±6.5 vs. 117±22ng/ml) vs. WT (p<0.05); however, pituitary prolactin content was not different. Blood prolactin was also decreased in male AgRP KO mice at baseline (4.2±0.5 vs. 7.6±1.3ng/ml) and after stress (60±4.5 vs. 86.1±5.7ng/ml) vs. WT (p<0.001). Pituitary prolactin content was lower in male AgRP KO mice (4.3±0.3 vs. 6.7±0.5μg/pituitary, p<0.001) vs. WT. No differences in blood or pituitary prolactin levels were observed in female AgRP KO mice vs. WT. Hypothalamic dopamine activity was assessed as the potential mechanism responsible for changes in prolactin levels. Hypothalamic tyrosine hydroxylase mRNA was measured in both genetic models vs. WT mice and hypothalamic dopamine and 3,4-dihydroxyphenylacetic acid (DOPAC) content were measured in male AgRP KO and WT mice but neither were significantly different. However, these results do not preclude changes in dopamine activity as dopamine turnover was not directly investigated. This is the first study to show that baseline and stress-induced prolactin release and pituitary prolactin content are reduced in mice with genetic alterations of the melanocortin system and suggests that changes in hypothalamic melanocortin activity may be reflected in measurements of serum prolactin levels.     

Reproductive effects of 6-chloromelatonin implants and/or injections in male and female Syrian hamsters (Mesocricetus auratus)

Adult female hamsters were injected each afternoon for 9 weeks with 2.5, 15 or 25 micrograms of melatonin or 6-chloromelatonin (CM). Each drug resulted in a significant dose-related depression in uterine, ovarian and anterior pituitary gland weights. Additionally, plasma and pituitary concentrations of prolactin fell with increasing dose of either indole whereas pituitary levels of LH and FSH were positively correlated with dose. There was no difference in effectiveness between the two drugs. Adult male hamsters treated for 10 weeks with daily afternoon injections of melatonin and a blank beeswax pellet had depressed testicular and accessory organ weights and plasma and pituitary concentrations of prolactin. Implantation of a 1 mg melatonin or CM beeswax pellet in hamsters concurrently receiving daily afternoon injections of melatonin prevented the organ weight and hormonal changes, except for plasma prolactin. Adult male hamsters treated for 10 weeks with daily afternoon injections of CM and a blank beeswax pellet had depressed reproductive organ weights and pituitary and plasma concentrations of prolactin; this depression in hormonal values and organ weights was totally prevented if the CM-injected hamsters were also bearing a beeswax-melatonin pellet. In conclusion, 6-chloromelatonin is as effective as melatonin with regards to antigonadotrophic and counter-antigonadotrophic effects in male and female Syrian hamsters.     

Uterine Notch2 facilitates pregnancy recognition and corpus luteum maintenance via upregulating decidual Prl8a2

The maternal recognition of pregnancy is a necessary prerequisite for gestation maintenance through prolonging the corpus luteum lifespan and ensuring progesterone production. In addition to pituitary prolactin and placental lactogens, decidual derived prolactin family members have been presumed to possess luteotropic effect. However, there was a lack of convincing evidence to support this hypothesis. Here, we unveiled an essential role of uterine Notch2 in pregnancy recognition and corpus luteum maintenance. Uterine-specific deletion of Notch2 did not affect female fertility. Nevertheless, the expression of decidual Prl8a2, a member of the prolactin family, was downregulated due to Notch2 ablation. Subsequently, we interrupted pituitary prolactin function to determine the luteotropic role of the decidua by employing the lipopolysaccharide-induced prolactin resistance model, or blocking the prolactin signaling by prolactin receptor-Fc fusion protein, or repressing pituitary prolactin release by dopamine receptor agonist bromocriptine, and found that Notch2-deficient females were more sensitive to these stresses and ended up in pregnancy loss resulting from abnormal corpus luteum function and insufficient serum progesterone level. Overexpression of Prl8a2 in Notch2 knockout mice rescued lipopolysaccharide-induced abortion, highlighting its luteotropic function. Further investigation adopting Rbpj knockout and DNMAML overexpression mouse models along with chromatin immunoprecipitation assay and luciferase analysis confirmed that Prl8a2 was regulated by the canonical Notch signaling. Collectively, our findings demonstrated that decidual prolactin members, under the control of uterine Notch signaling, assisted pituitary prolactin to sustain corpus luteum function and serum progesterone level during post-implantation phase, which was conducive to pregnancy recognition and maintenance.     

Prolactin receptor antagonism in mouse anterior pituitary: effects on cell turnover and prolactin receptor expression

Since anterior pituitary expresses prolactin receptors, prolactin secreted by lactotropes could exert autocrine or paracrine actions on anterior pituitary cells. In fact, it has been observed that prolactin inhibits its own expression by lactotropes. Our hypothesis is that prolactin participates in the control of anterior pituitary cell turnover. In the present study, we explored the action of prolactin on proliferation and apoptosis of anterior pituitary cells and its effect on the expression of the prolactin receptor. To determine the activity of endogenous prolactin, we evaluated the effect of the competitive prolactin receptor antagonist Δ1-9-G129R-hPRL in vivo, using transgenic mice that constitutively and systemically express this antagonist. The weight of the pituitary gland and the anterior pituitary proliferation index, determined by BrdU incorporation, were higher in transgenic mice expressing the antagonist than in wild-type littermates. In addition, blockade of prolactin receptor in vitro by Δ1-9-G129R-hPRL increased proliferation and inhibited apoptosis of somatolactotrope GH3 cells and of primary cultures of male rat anterior pituitary cells, including lactotropes. These results suggest that prolactin acts as an autocrine/paracrine antiproliferative and proapoptotic factor in the anterior pituitary gland. In addition, anterior pituitary expression of the long isoform of the prolactin receptor, measured by real-time PCR, increased about 10-fold in transgenic mice expressing the prolactin receptor antagonist, whereas only a modest increase in the S3 short-isoform expression was observed. These results suggest that endogenous prolactin may regulate its own biological actions in the anterior pituitary by inhibiting the expression of the long isoform of the prolactin receptor. In conclusion, our observations suggest that prolactin is involved in the maintenance of physiological cell renewal in the anterior pituitary. Alterations in this physiological role of prolactin could contribute to pituitary tumor development.     

口服他莫昔芬法建立ICR小鼠子宫腺肌病模型

目的使用口服他莫昔芬法建立ICR小鼠子宫腺肌病模型,并检测其病灶特征、动情周期、血管生成、子宫炎症等变化,以介绍和评价这一动物模型。方法新生ICR小鼠（15只）连续4 d滴喂他莫昔芬,并与同龄对照小鼠（15只）分别于42、85-95、135-145日龄处死,使用苏木素-伊红染色检测子宫病理改变;阴道脱落细胞法检测动情周期变化;免疫组化补体31（CD31）染色计算子宫微血管的密度、直径及所占面积比;逆转录-聚合酶链反应（RT-PCR）检测子宫缓激肽受体、神经激肽受体的基因表达。结果使用口服他莫昔芬法建立ICR小鼠子宫腺肌病模型的造模率为100%,且疾病严重程度随病程进展。部分给药小鼠可出现动情周期紊乱。85-95及135-145日龄给药小鼠子宫肌层微血管密度和面积比均高于对照小鼠（P〈0.05）。135-145日龄给药小鼠子宫缓激肽受体、神经激肽受体的基因表达较对照组明显升高（P〈0.05）。结论口服他莫昔芬法可方便、高效的建立腺肌病小鼠模型,出现腺肌病相关的血管生成、炎症状态、疼痛相关受体表达增高等特征,是研究腺肌病发生、发展的良好模型。     

Comparison of efficacy of cysteamine in depleting prolactin immunoreactivity in different hyperprolactinemic animal models

We have examined the effects of cysteamine on its ability to deplete prolactin in various states of hyperprolactinemia. Administration of subtoxic doses of cysteamine (75 and 150 mg/kg,sc) dramatically reduces serum prolactin levels as well as pituitary prolactin content in a dose-dependent manner in estrogen-primed brown Irish ACI female rats. A similar dose-dependent decrease in anterior pituitary prolactin levels was observed in two ectopic prolactin secreting pituitary tumor models (MtTW15 and 7315a). However, a significant reduction in serum prolactin levels was seen in these same tumor bearing animals at only the 150 mg/kg dose of cysteamine. Interestingly, the prolactin content of each of the prolactin secreting tumors, although reduced by cysteamine administration, the effect was neither dose-dependent nor as dramatic as that observed in the anterior pituitary gland proper. These data demonstrate that cysteamine can significantly lower prolactin concentrations in hyperprolactinemia. Further, ectopic prolactin secreting pituitary tissue appears less sensitive to the prolactin-depleting effects of cysteamine. This latter finding may explain, in part, why serum prolactin levels were not as severely reduced in the ectopic tumor bearing female rats as in estrogen-induced hyperprolactinemic animals.     

Pituitary and gonadal function in hypogonadotrophic hypogonadal (hpg) mice bearing hypothalamic implants

GnRH receptor values are 30-50% of normal in pituitaries of hpg male mice, and testicular LH receptors only 8% of normal (160.4 +/- 17.6 and 2013 +/- 208.1 fmol/testis respectively). In male hpg mice bearing fetal preoptic area (POA) hypothalamic implants for 10 days there was no change in pituitary GnRH receptors, pituitary gonadotrophin content, or seminal vesicle weight. However, testicular weights and LH receptors were doubled in 4/10 mice and 2 had increased serum FSH levels. Between 26 and 40 days after implantation pituitary GnRH receptors and pituitary LH increased to normal male levels, although at 40 days serum and pituitary FSH concentrations had reached only 50% of normal values. Testicular and seminal vesicle weights increased more than 10-fold by 40 days after implantation and LH receptors to 70% of normal. In hpg female mice bearing hypothalamic implants for 30-256 days pituitary gonadotrophin concentrations were normal, even though GnRH receptors reached only 60% of normal values (6.18 +/- 0.4 and 9.8 +/- 0.4 fmol/pituitary respectively). Serum FSH was substantially increased from values of less than 30 ng/ml in hpg mice to within the normal female range in hypothalamic implant recipients. Ovarian and uterine weights increased after hypothalamic grafting from only 4-5% to over 74% of normal values. LH receptors increased from 6.5 +/- 1.3 fmol/ovary for hpg mice to 566.9 +/- 39.2 fmol/ovary for implant recipients. Vaginal opening occurred about 23 days after implantation and these animals displayed prolonged periods of oestrus.(ABSTRACT TRUNCATED AT 250 WORDS)     

Hormonal regulation of protein kinase C in the mouse mammary gland

The hormonal regulation of protein kinase C (PKC) induction over 3 to 14 days was investigated in the mouse mammary gland in vitro and in vivo. In intact mice, estradiol (1 microgram/mouse injected daily for 2 weeks) stimulated PKC activity 70%, while progesterone (1 mg/mouse injected daily) inhibited it by 30%. Prolactin, whose levels were elevated for 2 weeks by two pituitary isografts, had no effect. When mammary gland explants were cultured in insulin and cortisol, the further addition of estradiol (1 ng/ml), progesterone (1 microgram/ml), or prolactin (1 microgram/ml) did not alter PKC activity after 3 days. These data suggest the following conclusions: although previous studies have implicated prolactin in the transient, calcium-phospholipid activation of PKC, it does not appear to elevate total levels of this kinase over prolonged periods. In contrast, the sex steroids do appear to affect long-term levels of this kinase; furthermore, this latter effect may be indirect.     

Modifications of plasma prolactin levels and catecholamine content in an ectopic anterior pituitary gland transplanted under the kidney capsule

In order to study the possible role on prolactin secretion of the catecholamines present in ectopic pituitaries, female rats bearing an anterior pituitary graft under the kidney capsule since day 30 of life and their sham-operated controls, were sacrificed at 1, 2, 4, 7, 15, 30, 45 and 60 days after the operation. Data obtained showed a significant increase in plasma prolactin levels in grafted rats versus controls from the 4th day on after the grafting (p less than 0.01) until the 60th day (p less than 0.001). Dopamine content in the ectopic pituitary of grafted rats was higher than in their own in situ pituitaries or on those of sham-operated rats until day 45 being similar to them afterwards. Norepinephrine was also present in the pituitary graft but was not detected in the in situ pituitaries. The grafting of an anterior pituitary gland in an ectopic location was able to induce changes in the local catecholaminergic control of the prolactin secretion.     

Secretory granules of prolactin cells of neonatally thyroidectomized female rats

In the anterior pituitary glands of neonatally thyroidectomized female rats sacrificed at 30 days of age, the prolactin granules were small and spherical in shape. The administration of thyroxine to neonatally thyroidectomized rats produced an obvious increase in the number and size of secretory granules in prolactin cells; comparatively large, pleomorphic secretory granules were frequently observed in these cells. These enlarged and pleomorphic granules closely resembled those observed in the prolactin cells of sham-operated control rats. These results may indicate that thyroxine stimulates the basic metabolism or cellular function of prolactin cells of neonatally thyroidectomized rats and leads to the formation of prolactin granules that are similar to those of sham-operated control rats.