Expression of cyclooxygenase-1 and cyclooxygenase-2, syndecan-1 and connective tissue growth factor in benign and malignant breast tissue from premenopausal women.

Stromal factors have been identified as important for tumorigenesis and metastases of breast cancer. From 49 premenopausal women, samples were collected from benign or malignant tumors and the seemingly normal tissue adjacent to the tumor. The factors studied, with real-time polymerase chain reaction (PCR) and immunohistochemistry, were cyclooxygenase-1 and cyclooxygenase-2 (COX-1 and COX-2), syndecan-1 (S-1) and connective tissue growth factor (CTGF). COX-1 and S-1 mRNA levels were higher in the malignant tumors than in normal and benign tissues. The COX-2 mRNA level was lower in the malignant tumor than in the normal tissue, while CTGF mRNA did not differ between the groups. COX-1 immunostaining was higher in stroma from malignant tumors than in benign tissues, whereas COX-2 immunostaining was higher in the malignant tissue. Glandular S-1 immunostaining was lower in malignant tumors compared to benign and normal tissues, and the opposite was found in stroma. Conclusively, mRNA levels of COX-1 and COX-2 were oppositely regulated, with COX-1 being increased in the malignant tumor while COX-2 was decreased. S-1 protein localization switched from glandular to stromal cells in malignant tissues. Thus, these markers are, in premenopausal women, localized and regulated differently in normal/benign breast tissue as compared to the malignant tumor.

Oxytocin receptors in dioestrous and anoestrous canine uteri.

The aim of the study was to localize oxytocin receptors (OTR) and measure mRNA expression of OTR in the canine uterus with and without the influence of progesterone. Uterine samples were taken from nine anoestrous and eight dioestrous bitches during ovariohysterectomy. Histological changes were evaluated in haematoxylin and eosin (HE)-stained samples. Purified polyclonal antibody for OTR was used in immunohistochemistry to localize receptors in uterine layers. Relative mRNA concentration of OTR was evaluated with real-time PCR from full-thickness uterine samples taken from the middle horn and the body. Myometrial smooth muscle cells, endometrial luminal epithelium (LE) and deep and superficial glandular epithelium were positively stained for oxytocin receptors in non-pregnant animals. No significant difference in staining intensity was detected between uterine middle horn and body. However, the staining intensity of LE was significantly higher in dioestrous than in anoestrous uteri (p < .05). Leucocytes and endothelium of blood vessels were also positively stained for OTR. Real-time PCR showed no significant differences in OTR mRNA expression between the middle horn and the body of the uterus, or between anoestrous and dioestrous uterus. No correlation was noted between OTR mRNA expression and blood progesterone concentration. In conclusion, despite the apparent inactivity, the uterus of the non-pregnant bitch expresses OTR. The distribution or relative expression of OTR does not differ between uterine horn and body in dioestrus or anoestrus except in LE. LE may have more oxytocin-dependent activity during dioestrus than anoestrus.

Endometrial population of oestrogen receptors alpha and beta and progesterone receptors A and B during the different phases of the follicular wave of llamas (Lama glama).

The aim of this study was to characterize the distribution of oestrogen receptor (ER)α and ERß as well as both progesterone receptors isoforms progesterone receptor (PR) A and PRB in the luminal and glandular epithelia and stroma of the endometrium during the different phases of the follicular wave in llamas. Six llamas were examined by transrectal ultrasonography, and a transcervical biopsy was obtained when a follicle at the growing, plateau and regressing phase was recorded. Blood samples were collected at the time of biopsy for hormone determinations. An immunohistochemical technique was used to study receptor populations. Total positive area was evaluated in the different cell types by Image Analysis. Mean diameter measurements of the largest follicle were 6.9, 8.5 and 5.1 mm (p < 0.001) and mean plasma oestradiol-17ß concentrations were 27.9 ± 3.26; 30.0 ± 2.79 and 24.0 ± 1.78 pmol/l (p = 0.32) during the growing, plateau and regressing phases, respectively. Immunostaining of ERα was higher in the luminal epithelium during the plateau and regressing phases (p < 0.05) than during the growing phase. More positive cells to ERß were observed in the glandular epithelium of the growing and plateau phases (p < 0.05) than during the regressing phase. A higher percentage of cells positive to PRB was recorded in the luminal and glandular epithelia during the plateau phase (p < 0.05), while the PRA immunostaining was similar among phases. In brief, this study showed an increased population of ERα and PRB in the luminal epithelium, and only of PRB in the glandular epithelium at the time when an ovulatory follicle is present. The physiological importance of these changes in llamas remains to be elucidated.

Expression of the androgen receptor and syndecan-1 in breast tissue during different hormonal treatments in cynomolgus monkeys.

OBJECTIVES: To analyze the expression of the androgen receptor(AR) and syndecan-1 in breast tissue during long-term hormonal treatment in cynomolgus monkeys. METHODS: Sixty oophorectomized macaques were randomized to receive either tibolone, conjugated equine estrogens (CEE), CEE + medroxyprogesterone acetate (MPA) or no hormonal treatment. Breast tissue was collected at necropsy after 2 years and stained for AR and syndecan-1. RESULTS: Apparent differences were seen between treatment groups as compared to untreated animals. AR expression was markedly increased by tibolone and suppressed by combined CEE/MPA. Both treatments increased syndecan-1 in stromal tissue, whereas CEE alone had no significant effect. CONCLUSIONS: We found alternative regimens for hormonal therapy to differ in their influence on two markers of importance for the development of breast cancer. The results may be relevant for the ongoing clinical discussion on the long-term safety of different hormonal treatments.

Gene expression analysis of human endometrial endothelial cells exposed to op'-DDT.

The endocrine disrupting chemical o, p'-dichlorodiphenyltrichloroethane (DDT) can affect reproductive organs, tissues and cells in several species. Treatment of human endometrial endothelial cells (HEECs) with 50 microM o,p'-DDT decreased their proliferation compared with the control. Microarray analyses revealed that o,p'-DDT affected biological processes such as the cell cycle, cell division, defence response and lipid and steroid metabolism, in cellular components such as the plasma membrane and chromosomes, with molecular functions involved in signalling, receptor and cytokine activity, confirming the results of the proliferation assay. Expression of five of the most differentially expressed genes identified in the microarray analysis was verified by real-time quantitative reverse transcription polymerase chain reaction in five HEEC cultures obtained from women in the proliferative phase and in five cultures obtained from women in the secretory phase of the menstrual cycle after treatment with o,p'-DDT. The present study supports our previous findings of decreased proliferation and increased cell death in response to o,p'-DDT and may offer important clues to the mechanisms of action of o,p'-DDT.

Effects of tibolone and conventional HRT on the expression of estrogen and progesterone receptors in the breast.

OBJECTIVE: There is evidence that long-term hormone replacement therapy (HRT) is associated with an increased breast cancer risk. The aim of this study was to assess the effects of tibolone on estrogen and progesterone receptors in comparison to the effects of conventional HRT in the breast of surgically postmenopausal macaques. METHOD: Sixty macaques were bilaterally ovariectomized 3 months before hormonal treatment was initiated. The animals were randomized into four treatment groups, including tibolone (TIB), conjugated equine estrogens (CEE), conjugated equine estrogens+medroxyprogesterone acetate (CEE+MPA) and control animals (C). After 2 years treatment, breast tissues were collected, fixed and paraffin embedded. Immunohistochemistry assays with monoclonal antibodies for estrogen receptors (ERalpha and ERbeta) and progesterone receptors (PRA and PRB) were performed. RESULTS: The expression of ERalpha was markedly decreased in the CEE+MPA group as compared to C and TIB groups. The TIB group was not different from the C and CEE groups. No significant differences were found for ERbeta immunostaining. The expression of PRA was strongly increased in the TIB group as compared to the C and CEE+MPA groups. Immunostaining of PRB was increased in the CEE and TIB treated animals as compared to both C and CEE+MPA groups. CONCLUSIONS: Tibolone increased the expression of both PRA and PRB, without affecting ERalpha and ERbeta expression in the macaque breast. These findings indicate that the effects of tibolone in breast tissue could be mediated via differential regulation of PRA and PRB isoforms and therefore distinct from those observed with conventional HRT.

Expression of syndecan-1 in paired samples of normal and malignant breast tissue from postmenopausal women.

BACKGROUND: The mammary stroma is important for modulating epithelial breast cell response to sex steroid hormones. Proteoglycans, such as syndecan-1, promote the integration of cellular signals. MATERIALS AND METHODS: The immunohistochemical expression of syndecan-1 and of the androgen receptor (AR) was analyzed in paired samples of cancer and adjacent normal tissue from postmenopausal women. RESULTS: Normal and cancer tissue showed dramatic differences in the expression of syndecan-1. In malignant breast stroma, mean values were more than 10-fold higher than in normal tissue (p<0.001). There was also a marked redistribution from the epithelium to the stroma. The expression of AR was on average 2-fold higher in cancerous than in normal tissue (p<0.01). CONCLUSION: Breast cancer patients have very different prognoses. Syndecan-1 and the AR may be new molecular markers relevant to clinical outcome. The redistribution from the epithelium and the dramatic increase of syndecan-1 in cancerous stroma may be related to the natural history of the disease.

Differential estradiol effects on estrogen and progesterone receptors expression in the oviduct and cervix of immature ewes.

In order to study the effect of estradiol-17beta (E2) on estrogen (E) and progesterone (P) receptors expression in oviduct and cervix of lambs, their respective transcripts (ERalpha mRNA and PR mRNA) were determined by solution hybridization and the receptor proteins (ER and PR) by binding assays after E2 treatments. Lambs (n=4 in each group) were not treated or treated with one, two or three i.m. injections of E2 (1 microg/kg) at 24 h of interval. Tissues were obtained 12 or 24 h after the last E2 injection. Estradiol treatments increased ERalpha mRNA and PR mRNA concentrations in an organ-dependent manner: transitory in the oviduct while maintained in the cervix. The E2 effect on the oviductal and cervical ER and PR concentrations were biphasic, with an initial reduction of receptors content that was followed by restoration. The ER restoration in oviduct was earlier than in the cervix. In summary, this study shows that E2 treatments may exert an inductive effect in ERalpha mRNA and PR mRNA levels and a biphasic effect in ER and PR concentrations in oviduct and cervix of immature ewe. These E2 effects varied in timing and strength depending on the organ of the reproductive tract.

Induction of the estrogen receptor by growth hormone and glucocorticoid substitution in primary cultures of rat hepatocytes.

Hepatic estrogen receptors (ER) mediate estrogenic effects on mammalian liver metabolism and are thereby involved in the regulation of important physiological/pathological processes, such as coagulation, atherosclerosis, and hypertension. The regulation of the formation of the ER in primary cultures of rat hepatocytes was studied by assaying ER and ER mRNA under different endocrine conditions. The ER concentration was measured using two different methods, a ligand-binding technique and an ER enzyme immunoassay. The results obtained by the two methods showed good correlation, and linear regression analysis gave a correlation coefficient of 0.95. ER concentrations fell to low steady state levels within 16 h after establishing the cell culture and remained low in the absence of hormonal substitution. Upon medium supplementation with pituitary GH and the glucocorticoid dexamethasone (DEX) in combination, the ER concentration increased 6-fold from 4.2 +/- 1.0 to 25.8 +/- 7.0 fmol/mg cytosolic protein. ER mRNA was measured by solution hybridization. Substitution with GH and DEX in combination increased ER mRNA to 210 +/- 14% of control levels. No effect on ER mRNA stability was seen after hormone treatment. It is concluded that the regulatory effects of GH and DEX on the hepatic ER in this in vitro system are very similar to the effects of these hormones under in vivo conditions. The inducible expression of the ER has never before, to our knowledge, been demonstrated in any mammalian liver cell culture system.

Growth hormone regulation of SOCS-2, SOCS-3, and CIS messenger ribonucleic acid expression in the rat.

The SOCS (suppressors of cytokine signaling) proteins have been suggested to function as inhibitors of cytokine receptor signaling. We have analyzed SOCS-2, SOCS-3, and CIS expression in relation to GH actions in the rat. SOCS-2, SOCS-3, and CIS transcripts were detected in various GH responsive tissues, including liver, muscle, and fat. In addition to the finding that different tissues express different levels of SOCS-2, SOCS-3, and CIS messenger RNA (mRNA), the steady-state levels of these SOCS transcripts were dependent on the endocrine status of the animal. SOCS-3 expression was 5-fold higher in fat from old compared with younger rats. Hypophysectomy reduced the levels of SOCS-2 and CIS mRNA in liver, muscle, and fat, whereas SOCS-3 expression was unchanged. Using primary cultures of rat hepatocytes, GH was shown to increase SOCS-2, SOCS-3, and CIS mRNA levels with different kinetics. SOCS-3 was rapidly and transiently induced, whereas SOCS-2 and CIS were increased in a slower fashion. Glucocorticoids blocked GH-induced SOCS-3 expression in cultured hepatocytes, whereas SOCS-2 and CIS expression was potentiated. Our data fit well with a concept of SOCS proteins acting as modulators of GH signal transduction.

The hormonal regulation of the oestrogen receptor in rat liver: an interplay involving growth hormone, thyroid hormones and glucocorticoids.

The regulation of the formation of the hepatic oestrogen receptor (ER) in adult female rats was studied by assaying steady state levels of ER and ER messenger RNA under different endocrine conditions. Hypophysectomy (HX) drastically reduced ER levels from 67.5 +/- 7.9 to 8.4 +/- 0.5 (means +/- S.E.M.) fmol/mg cytosolic protein. Continuous infusion of growth hormone (GH) to HX animals tripled ER and doubled ER mRNA levels. Treatment with triiodothyronine (T3) in a high dose (10 micrograms/day) doubled ER mRNA levels. The effects of T3 were dose-dependent, since a lower dose (1 microgram/day) increased neither ER nor ER mRNA levels. ER mRNA concentrations were increased by GH to 481 +/- 44% and by T3 to 372 +/- 35% of HX control levels 4 h after single injections of the hormones in HX animals. The glucocorticoid dexamethasone (DEX) alone increased neither ER nor ER mRNA levels in HX animals. DEX and GH in combination increased ER 5-fold and ER mRNA 2-fold compared with control levels in HX animals, whereas DEX and T3 in combination increased neither ER nor ER mRNA levels. Treatment with prolactin affected neither ER nor ER mRNA levels in HX rats. Insulin-like growth factor I (IGF-I) mRNA and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA levels were measured. GAPDH mRNA levels were increased 2.5-fold in HX rats by DEX and T3 in combination and almost 2-fold by DEX and GH in combination. IGF-I mRNA levels in HX rats were increased 4.5-fold by continuous infusion of GH alone, 6-fold by GH and T3 in combination, and 2.5-fold by GH and DEX in combination. These data indicate that both GH and T3 act directly on the liver to increase ER mRNA levels. GH, the most important of these hormones, also acts at the translational and/or post-translational level to increase ER protein levels. DEX treatment suppresses the stimulatory effects of T3, but not of GH.

The effect of long-term treatment with steroid hormones or tamoxifen on oestrogen receptors (alpha and beta) in the endometrium of ovariectomized cynomolgus macaques.

The effects of oestrogen are mediated by two specific intracellular receptors, oestrogen receptors (ER) alpha and beta, which function as ligand-activated transcriptional regulators. Ovariectomized macaques (Macaca fascicularis) were used to study the regulation of ERalpha and ERbeta in the endometrium by immunohistochemistry and in situ hybridization after long-term hormone treatment. Animals were treated continuously for 35 Months with either conjugated equine oestrogen (CEE), medroxyprogesterone acetate (MPA), combined CEE/MPA, or tamoxifen (TAM). Treatment with CEE/MPA down-regulated ERalpha in the superficial glands. In the superficial stroma the ERalpha level was lower in the CEE/MPA group than in the CEE and MPA groups. ERbeta immunostaining was faint with minor variation in response to treatment, but increased in the superficial stroma after MPA treatment. The ratio of ERbeta/ERalpha increased in superficial stroma and gland after CEE/MPA treatment, and also in stroma after MPA and TAM. Cystic endometrial hyperplasia was observed in TAM-treated animals, in combination with a high level of ERalpha protein expression. The present data show that long-term hormone treatment affects the ERalpha and ERbeta protein levels in the endometrium. The balance between ERalpha and ERbeta seems to be important for the proliferative response to oestrogen.

Decreased expression of thioredoxin and glutaredoxin in placentae from pregnancies with pre-eclampsia and intrauterine growth restriction.

Pre-eclampsia is one of the major contributors to perinatal morbidity. This study was performed to test a hypothesis which suggests that pre-eclampsia is associated with inadequate control by the thioredoxin system and other related reducing systems. Placental tissue from normal pregnancies (NC), severe pre-eclampsia with fetuses small for gestational age (SPE), mild pre-eclampsia with fetuses small for gestational age (MPE) and pregnancies with small fetuses for gestational age without any sign of pre-eclampsia (IUGR) was collected immediately after delivery. The mRNA levels for thioredoxin and glutaredoxin were determined using a solution hybridization method and the distribution of the proteins in a normal placenta was analysed by immunohistochemistry. Results showed that the thioredoxin mRNA level in the SPE group was decreased to one third of the level in the NC group. Also the IUGR group showed a significant decrease. The glutaredoxin mRNA level in the SPE group was one half of that seen in the NC group. There was significant correlation between the mRNA levels for thioredoxin and glutaredoxin, both in the normal and growth restricted pregnancies. We conclude that the thioredoxin and glutaredoxin reducing systems are affected in placenta from pregnancies with pre-eclampsia and/or growth restriction of fetuses, and that the decrease correlates to the severity of the condition.

Dexamethasone attenuates the estradiol-induced increase of IGF-I mRNA in the rat uterus.

In recent years growth factors, e.g. insulin-like growth factor-I (IGF-I), transforming growth factor-alpha (TGF-alpha) and epidermal growth factor (EGF), have been considered as mediators of estradiol-stimulated growth in the uterus. In the liver, dexamethasone (Dex) has been shown to inhibit the IGF-I mRNA increase induced by growth hormone (GH). In the present study the influence of Dex on estradiol-stimulated induction of uterine IGF-I mRNA was examined. The concentration of IGF-I mRNA in the uterus and liver was monitored, as well as the levels of ER mRNA and estrogen receptor (ER). Since it has been previously shown that the maximal induction of uterine IGF-I mRNA after estradiol (E2) stimulation occurs after 21-24 h, Dex was administered to ovariectomized (ovx) rats 3 h before an E2 injection and 24 h before sacrifice. There was a significant decrease in IGF-I mRNA in the Dex+E2 treated rats compared to the rats given E2 only. In both groups an increase was seen compared to the level in the ovx control group. The uterine ER mRNA levels in E2 and Dex+E2 treated animals were significantly elevated compared to the ovx control. There were no significant changes in uterine ER content after hormone treatment compared to the level in ovx control rats. In the liver no effects on IGF-I mRNA were detected. Hepatic ER mRNA was significantly increased in the E2 treated group, compared to both the ovx control group and the animals that received Dex+E2. The hepatic ER level was also increased in the E2 treated group compared to the ovx control and the group which received Dex+E2. In conclusion, Dex does attenuate the estrogen-induced uterine IGF-I mRNA increase in ovx rats. In addition to this, Dex was found to inhibit the estrogen-induced increase in ER and ER mRNA in the liver of ovx rats.

Influence of blockers for the estrogen receptor (ER) and type 1 IGF-receptor on the levels of ER, ER mRNA and IGF-I mRNA in the rat uterus.

The effects on the uterine concentration of the estrogen receptor (ER), ER mRNA and IGF-I mRNA were monitored in ovariectomized (OVX) rats treated with blockers for the estrogen receptor (ER) (ICI 182780) or the type 1 IGF receptor (H-1356), alone or in combination with estradiol (E2). The hormone-mediated increase in uterine wet weight after E2 treatment was prevented by a simultaneous injection of ICI 182780. The levels of IGF-I mRNA and ER mRNA increased in rats given estradiol (E2), but not in those also receiving ICI 182780. The level of uterine ER was decreased in all animals that received ICI 182780. H-1356 (H) given as a continuous infusion decreased the estradiol-induced increase in uterine wet weight 24 h after a single E2 injection, but not 48 h after the first (of two) E2 injections. The IGF-I mRNA was increased in the E2 treated group after 24 h, and in both the E2 and H + E2 treated groups after 48 h. The ER mRNA was increased in the E2 treated group after 24 h, but not after 48 h. When H-1356 was given as two single injections and estradiol was or was not administered together with the second injection, the uterine wet weight was not increased as in the group receiving E2 only. The levels of IGF-I mRNA as well as ER mRNA were increased both after E2 and H + E2 treatment. In conclusion, the uterine growth stimulated by E2 was prevented by simultaneous treatment with ICI 182780. In addition a type 1 IGF-receptor blocker, which is an IGF-I analogue inhibiting the autophosphorylation of the receptor, also prevented the hormone-induced uterine growth after 24 h, but not after 48 h, when given as a continuous infusion. The results imply that the growth process stimulated by estradiol utilizes the ER receptor, and also the type 1 IGF-receptor during the first 24 h after E2 treatment.

Androgen regulation of the insulin-like growth factor-I and the estrogen receptor in rat uterus and liver.

For the first time testosterone is shown to be an important regulator of the insulin-like growth factor-I (IGF-I) in the rat uterus under in vivo conditions. In this study the regulation of IGF-I and the estrogen receptor (ER) by gonadal steroids in the uterus and liver of female rats was monitored. The ER level was assayed by hormone binding after treatment with testosterone, 5 alpha-dihydrotestosterone or estradiol and specific mRNA species were analyzed by a solution hybridization/RNase protection assay using 35S-labeled RNA probes. Ovariectomized rats restored uterine weight after treatment with testosterone. Uterine IGF-I mRNA was more than 20-fold higher in testosterone treated rats compared to untreated ovariectomized controls after 48 h treatment. The effects of testosterone on ovariectomized animals was followed in a timecourse study. Testosterone administration increased uterine IGF-I mRNA expression during the first 48 h and the maximally induced level was maintained throughout the duration of the experiment (168 h). Since induction of IGF-I mRNA by estrogen is transient, these data indicate that androgen and estrogen increase IGF-I mRNA by different mechanisms. Regulation of IGF-I mRNA by gonadal steroids was also studied in hypophysectomized animals. The rats were given either testosterone, 5 alpha-dihydrotestosterone or estradiol, and uterine IGF-I mRNA was measured after 1 week of treatment. At this timepoint estrogen treated rats showed levels of IGF-I mRNA not significantly different from those of hypophysectomized controls. In contrast testosterone and 5 alpha-dihydrotestosterone increased the IGF-I mRNA level 30 and 40 times, respectively, relative to hypophysectomized control animals. Since 5 alpha-dihydrotestosterone is not convertable to estrogen, the induction by testosterone was considered to be a true androgenic phenomenon.

Regulation of thioredoxin mRNA in the rat uterus by gonadal steroids.

Estradiol has been shown to increase the level of thioredoxin mRNA in the uterus of the ovariectomized (ovx) rat. In this study the influence of progesterone, androgens, the anti-estrogen ICI 182780 and the anti-androgen Flutamid on thioredoxin expression, has been studied in the rat uterus. Thioredoxin mRNA concentrations were determined by solution hybridization. Ovx rats treated with progesterone alone showed no effect on thioredoxin expression. Combined treatment of ICI 182780 and estradiol attenuated the estradiol-induced increase in thioredoxin mRNA. When ovx rats were treated with a testosterone depot, the amount of thioredoxin mRNA was increased five-fold after 48 h and remained at that level during the rest of the 168 h monitored. A similar increase in thioredoxin mRNA could be seen after 5alpha-dihydrotestosterone treatment, indicating a true androgenic effect. In addition, the anti-androgen Flutamid attenuated the thioredoxin mRNA increase seen after 5alpha-dihydrotestosterone treatment alone. It is concluded that thioredoxin mRNA is regulated by growth promoting gonadal steroids in the rat uterus. The attenuation of the estrogen and androgen-induced increases of the thioredoxin mRNA with ICI 182780 and Flutamid, indicate that the effect is mediated via the estrogen receptor and androgen receptor respectively. None of these hormones affected the hepatic thioredoxin mRNA level in the same animals.

Estrogenic influence on the regulation of hepatic estrogen receptor-alpha and serum level of angiotensinogen in female rats.

The majority of data regarding biological effects of estrogens is based on studies in male rats or ovariectomized (Ovx) female rats. Therefore, in this study, the effects of estradiol treatment on the regulation of the hepatic estrogen receptor and the level of circulating angiotensinogen were examined in the intact female rat. The data were compared with that of the hypophysectomized (Hx) rat. Animals were treated with either low (physiological) or high (pharmacological) doses of estrogen. In intact rats, the hepatic estrogen receptor (ER) level increased with increasing doses of estrogen. This was in contrast to the Hx rats where growth hormone (GH) and dexametasone (Dex) in combination were the sole modulators of the estrogen receptor. The angiotensinogen level increased in normal rats after estrogen administration in a dose dependent manner, regardless of the mode of administration. The pure antiestrogen ICI 182 780 efficiently blocked the increase in circulating angiotensinogen. The conclusion is that in the normal female, estrogens are important modulators of the serum angiotensinogen level.

Regulation of insulin-like growth factor-I and thioredoxin expression by estradiol in the reproductive tract of the prepubertal female lamb.

Estradiol (E(2)) has been shown to be an important uterine growth promoting molecule in the ovariectomized (ovx) rat, which increases the mRNA levels of insulin-like growth factor-I (IGF-I) and the redox enzyme thioredoxin. The aim of this study was to explore the role of E(2) in the regulation of IGF-I and thioredoxin in the reproductive tract of the prepubertal female lamb. Twenty 3-month-old lambs were treated with i.m. injections of E(2) at 24 h intervals. The animals were sacrificed 12 or 24 h after the last injection, and 72 h was the longest treatment period. The mRNA levels of thioredoxin and IGF-I were determined by a solution hybridization technique. There was a 5-fold increase in the cervical IGF-I mRNA level 12 h after the first E(2) injection. The uterine IGF-I mRNA level was doubled after 12 h and this increase was maintained during the rest of the experimental period. The IGF-I mRNA level in the oviducts was more than doubled 12 and 24 h after the E(2) injection, then the level decreased towards the initial level. The thioredoxin mRNA level in the cervix was increased 4-fold after 24 h, whereas no significant effect was seen in the uterus. The thioredoxin mRNA level in the oviduct was more than doubled 12 and 24 h after the first E(2) injection. Thus, estradiol regulates the expression of IGF-I and thioredoxin in the reproductive tract of prepubertal lambs.

Expression of sex steroid receptors and IGF-1 mRNA in breast tissue--effects of hormonal treatment.

The mechanisms behind increased breast tissue proliferation and a possibly increased breast cancer risk in women using hormonal contraception (HC) and hormonal replacement therapy (HRT) are incompletely understood. We analyzed breast tissue from 20 premenopausal and seven postmenopausal women undergoing reduction mammoplasties for estrogen receptor (ER) and progesterone receptor (PR) content as well as mRNA levels for ER, PR and insulin-like growth factor-1 (IGF-1). The receptor values were correlated to IGF-1 mRNA concentrations and levels of steroid and peptide hormones and SHBG. In women using HC, we found significantly lower ER values (p = 0.02) but non-significantly lower ER mRNA levels compared to those in naturally cycling women. PR and PR mRNA were no different. Women on HC displayed a higher breast tissue proliferation (p = 0.05) expressed as Ki-67, MIB-1 positivity, which was correlated with IGF-1 mRNA (r(s) = 0.82, p = 0.04). Since the concentration of sex steroid receptors in breast tissue is comparatively low and steroid receptors are down-regulated during hormonal treatment, mechanisms other than direct sex steroid receptor action are likely to be present. Our results suggest a role for IGF-1 in the proliferative response of breast tissue during exogenous hormonal treatment.