Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0006142 (breast cancer)
 160,383 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An understanding of the basic mechanisms of hormone action is becoming an important part of a clinician's training. With the advent of radioreceptor assays and their comparison with radioimmunoassays, we are becoming increasingly aware that the normal physiological function of a hormone is not necessarily dependent on "normal" levels of hormone being present in the plasma. Even if plasma levels are normal, if a particular target cell lacks the receptor for the particular hormone the target tissue will not respond to the hormone. It has been shown, for example, by many workers that steroid hormones act on their cells via a receptor located in the cytoplasm of the target cells (1-4). Since the presence or absence of such receptors are becoming increasingly important in terms of unexplained infertility, endometrial carcinoma and breast cancer, it is necessary that the practicing clinician be familiar with the concept of receptors and have some understanding of their mode of action. In this brief presentation, I will explain certain terminology and summarize the state of the art so that you can critically read the literature concerning new developments in the area of hormone action which is to become increasingly important in the next few years. I will discuss some of the aspects of the mechanism of peptide hormones such as LH and FSH but will devote most of my attention discussing the details of steroid hormone action since our knowledge in this area is much more complete. I will also explain the terms frequently discussed in the literature concerned with hormone-receptor interactions.
 ...
PMID:Hormone-receptor interactions--basic mechanisms. 1 18

An attempt was made to classify human pituitary cell types by electron microscopic immunohistochemistry. The immunoperoxidase technique involving the use of the peroxidase-antiperoxidase complex was applied to thin sections of human pituitaries removed surgically for breast cancer or diabetic retinopathy. Using specific antibodies against human PRL, GH, beta-FSH, beta-LH, beta-TSH, and porcine ACTH, the localization of each hormone was studied. Identification of 5 human pituitary cells was possible: 1) The PRL-secreting cell contains round or slightly ovoid secretory granules of a diameter of 275-350 nm. 2) The GH-secreting cell is densely granulated with granule diameters ranging from 350-500 nm. 3) The gonadotrophic cell, which stains for both beta-FSH and beta-LH, is characterized by the presence of a varying number of secretory granules ranging from 275-375 nm. 4) The cortico-lipotrophic cell has numerous granules of about 375-550 nm in diameter. 5) The TSH-secreting cell contains small secretory granules of about 125-200 nm in diameter. Another cell type of which the small secretory granules of about 100 nm in diameter could not be stained by any of the antisera was also observed. This ultrastructural identification of human pituitary cells should contribute to a better understanding of the pathophysiology of the human pituitary.
 ...
PMID:Identification of human anterior pituitary cells by immunoelectron microscopy. 22 40

The hormonal features of the menstrual cycle determined by measurement of serum LH, FSH, oestradiol, progesterone and prolactin were normal in thirteen breast cancer patients clinically disease free and not taking anti-tumour therapy. Results of similar studies during seven menstrual cycles in four patients on an adjuvant therapy programme of L-phenylalanine mustard (L-PAM) + 5-flurouracil (5-FU) also had normal hormonal characteristics after three to fourteen courses of chemotherapy. Amenorrhoea with elevated gonadotrophins occurred after seven courses of chemotherapy in one 48-year-old woman. Adjuvant chemotherapy does not appear to result in major alterations in hormone secretion during menstrual cycles of women who continue to menstruate while on therapy.
 ...
PMID:Hormonal regulation of the menstrual cycle in women with breast cancer: effect of adjuvant chemotherapy. 45 42

Urinary and blood hormonal profiles were studied throughout a monthly cycle in a patient with familial breast cancer. Two comparison cohorts (one high-risk and one low-risk) were studied concurrently. Findings disclosed that our breast cancer-affected patient showed a distinctive hormonal pattern characterized by significant elevation throughout the cycle of plasma estrone, estradiol, and prolactin. Save for a depression in plasma FSH in the early follicular phase, this hormone, as wells as LH and progesterone patterns in our patient, were similar to the comparison cohorts. Urinary estrone and estradiol patterns in our patient were elevated early in the follicular phase. Our patient also showed a depression in urinary estrone, estradiol, and estriol following ovulation, which persisted throughout the luteal phase. Blood and urinary hormone patterns in the high-risk cohort were not demonstrably different from the low-risk cohort, with the exception of plasma prolactin. The results on the latter hormone showed an unexpected significant depression throughout most of the menstrual cycle in this low-risk cohort. We conclude that estrone and estradiol elevations, as clearly evidenced in our breast-cancer-affected patient, may provide clues that ultimately might be used as an etiologic discriminant for breast cancer risk and which may also play a pathogenic role in this disease. Since this involved a single patient, our conclusions must be interpreted cautiously.
 ...
PMID:Endocrine profile in a patient with familial breast cancer: a case-control study. 49 52

Treatment of breast cancer by combination therapy induced luteal insufficiency, anovulatory cycles and sometimes hypergonadotropic amenorrhea in premenopausal women with previously normal mentrual cycles and ovarian function. In chemotherapy induced amenorrhea 17 beta-estradiol levels were those found in ovarectomised or postmenopausal women. Chemotherapy affected the ovary itself and not the hypothalamus or pituitary, the negative feedback mechanisms remaining intact. The ovary of perimenopausal patients was much more sensitive to cytotoxic drugs; following a short time chemotherapy hypergonadotropic amenorrhea invariably developed and the ovary seemed to be again the prime site of action. Postmenopausal patients continued to have physiologically high LH and FSH plasma concentrations and low plasma levels of prolactin and 17 beta-estradiol under cytotoxic treatment.
 ...
PMID:The effect of combination chemotherapy on ovarian, hypothalamic and pituitary function in patients with breast cancer. 51 32

The effect of cyclophosphamide (CY) on ovarian function was studied in patients with breast cancer receiving prolonged daily administration of this agent (100 mg/day) after radical surgery. Out of 18 premenopausal patients that received 8.4-39.9 g CY, 15 developed permanent amenorrhea. The average dose given before the onset of amenorrhea was 5.2 g in patients in their 40s and 9.3 in their 30s. Urinary estrogens and serum progesterone were measured weekly for approximately 6 months postoperatively in six patients receiving CY. After the onset of amenorrhea, the levels of both hormones ceased to show their normal cyclic changes and remained low persistently, meanwhile serum FSH and LH were markedly elevated. No ovarian follicle was histologically found in three amenorrheic patients who underwent therapeutic oophorectomy after CY therapy. These findings indicate that CY induced primary ovarian failure.
 ...
PMID:Cyclophosphamide-induced ovarian failure and its therapeutic significance in patients with breast cancer. 85 40

The fine structure of gonadotrophs has been investigated in surgically removed pituitary glands of 12 women who because of disseminated breast cancer, underwent bilateral ovariectomy at various periods before hypophysectomy. Compared with the adenohypophyses of 3 non-ovariectomized female subjects with diabetes mellitus, electron microscopy revealed that two cell types were affected by gonadectomy. These cell types corresponded to those which were regarded as FSH gonadotrophs and LH gonadotrophs in previous studies. In addition in the adenohypophyses stimulated by removal of the ovaries, intermediary cell types began to appear suggesting a transformation of LH gonadotrophs to FSH gonadotrophs. The most conspicuous change following gonadectomy was the formation of castration cells. These cells arose from FSH gonadotrophs and exhibited ultrastructural features interpreted as representing the morphologic manifestations of sustained hypersecretion of gonadotrophins. It seemed that castration cells have a limited life span and in their advanced stages of development they show ultrastructural signs indicative of irreversible involution.
 ...
PMID:Gonadotrophs following removal of the ovaries: a fine structural study of human pituitary glands. 122 14

The protective effect of dietary fiber on breast cancer development might be explained by the interaction between dietary fiber and hormonal processes. We studied the effects of dietary fiber and the effects of a reduced energy intake on the exposure of mammary tissue to both estrogens and progesterone, as well as the blood plasma levels of these steroids and of LH and FSH. Adult female Fisher rats were fed ad libitum either a low-fiber diet (0.5% dietary fiber based on wheat flour) or a high-fiber diet (9.2% dietary fiber based on wheat bran). A third group was used to control for the reduced energy intake of the high-fiber group and was fed the low-fiber diet restricted. Energy intake was similar for the second and third groups. Four out of 14 rats of the high-fiber group and 4 out of 15 rats of the restricted low-fiber groups were not in cycle after seven weeks on the experimental diets, indicating that the estrous cycle was significantly affected by a reduced energy intake. Exposure of mammary tissue to estrogens did not differ among the groups, as measured by estrone, estradiol-17 beta, estriol and peroxidase activity. During the peak period, plasma LH levels were significantly higher in the high-fiber group than in the two low-fiber groups. FSH and progesterone plasma levels were unaffected by the experimental diets. It is concluded that dietary fiber affects the hormonal processes involved in breast cancer development. The increased LH levels indicate an increased estrogen production in the ad libitum high-fiber group.
 ...
PMID:Effects of wheat bran on blood and tissue hormone levels in adult female rats. 132 21

During the last two decades, considerable experimental evidence has been collected indicating that epithelial ovarian cancer might be gonadotropin dependent. LH and FSH receptors have been described in some of these tumors. The proliferation of ovarian cancer cells could be stimulated in vitro by gonadotropins. Suppression of endogenous LH and FSH secretion by GnRH-agonist treatment inhibited the growth of experimental or heterotransplanted ovarian cancers in various animal models. A number of recent phase II clinical trials have shown that the application of GnRH-agonists can lead to remission or stable disease in patients with relapsed advanced ovarian cancer. At present, prospective controlled clinical studies are being performed to assess the efficacy of GnRH-agonist treatment in addition to conventional surgical and cytostatic therapy in ovarian cancer in FIGO stages III and IV. Also, direct effects of GnRH analogues on ovarian cancer seem possible: a GnRH-like protein has been found in the human ovary. Our group discovered and partially characterized a specific GnRH-binding site (mol. wt 63.2 kDa) in ovarian cancer which is very similar to other human extrapituitary GnRH-binding sites of the low affinity, high capacity type, e.g. in breast cancer or the placenta. Recently, other groups have described also high affinity GnRH-agonist binding sites in ovarian cancer as well as in other extrapituitary tissues. First results from our laboratory indicate that the proliferation of certain ovarian cancer cell lines in vitro is reduced by both agonistic and antagonistic analogues of GnRH. Other authors were able to inhibit gonadotropin-induced in vitro proliferation of ovarian cancer cell lines by co-incubation with a GnRH-agonist.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Intracellular actions of gonadotropic and peptide hormones and the therapeutic value of GnRH-agonists in ovarian cancer. 138 55

Circulating preoperative levels of DHEA-S, androstenedione and SHBG were measured in 40 premenopausal and 49 postmenopausal breast cancer patients, and in 30 and 15 age-matched healthy controls, respectively. Moreover, the levels of LH, FSH, prolactin, estradiol, progesterone, testosterone, DHEA-S, androstenedione and SHBG of Stage II breast cancer patients were compared with advanced patients and also with controls. In premenopausal patients the levels of steroid hormones were significantly low whereas those of peptide hormones were significantly high. On the contrary, in postmenopausal patients, except DHEA-S, all other hormones were significantly elevated in comparison with controls. In premenopausal patients, DHEA-S, androstenedione, estradiol, progesterone, and testosterone decreased as stage advanced with concomitant increase of SHBG, LH, FSH and prolactin when compared with hormone levels of Stage II patients. In postmenopausal advanced breast cancer patients, when compared with Stage II patients, the levels of SHBG, LH, FSH, and prolactin increased significantly, while DHEA-S, androstenedione, estradiol, and progesterone decreased as stage advanced.
 ...
PMID:Endocrine status in stage II vs. advanced premenopausal and postmenopausal breast cancer patients. 138 48


1 2 3 4 5 6 7 8 9 10 Next >>