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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Prolactin binding in ovariectomy-responsive and ovariectomy-nonresponsive carcinoma in the Wistar/Furth rat is compared. The time course of binding of prolactin at 4, 24, ad 37 degrees for mammary tumor (MTW9) coimplanted with MtTW10, a mammosomatotropic pituitary tumor (MTW9-MtT) or with MTW9 maintained with daily perphenazine injections (MTW9-P) was measured. Maximum binding to membranes of both tumors occurred at 4 degrees after about 30 hours incubation. The binding was inhibited by polypeptide hormones that possess lactogenic activity. Mammary tumors from animals maintained on perphenazine had a 4-fold greater binding capacity than did tumors from MtT-supported animals. When perphenazine therapy was halted the binding capacity of MTW9-P membranes was unaffected. This result held when MTW9-P animals were ovariectomized. Resection of MtT resulted in tumor regression, a fall to normal of serum prolactin, and a nearly 3-fold increase in prolactin binding. Scatchard plots of prolactin binding data yield an apparent affinity constant, K(a) of 1.2 X 10(9) liters/mole for both tumors.
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PMID:Prolactin binding in ovariectomy-responsive and ovariectomy-nonresponsive rat mammary carcinoma. 1 19

Prolactin iodinated by lactoperoxidase method showed immunologically, electrophoretically and biolo9gically similar properties to native prolactin and possessed enough specific radioactivity for receptor studies. 1251-prolactin was incubated with mouse mammary tissues at 8 days of lactation. Both binding and release of 1251-prolactin depended on incubation time and temperature and were maximal at 37 degrees C. Michaelis constant was estimated to be 1.4 X 10(-9) M from Lineweaver-Burk plot and to be 1.2 X 10(-9) M from id-value of the dose-response curve for displacement with native prolactin. Total number of binding sites for prolactin was 1.38 X 10(-15) mole per mg weight of tissue. Ovine prolactin, human growth hormone and human placental lactogen complete with 1251-prolactin and dose-response curves for these three hormones were all parallel. These results suggest the existence of a specific receptor site with high affinity for prolactin in lactating mouse mammary glands.
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PMID:A receptor site for prolactin in lactating mouse mammary tissues. 17 1

Since liver is a target for growth hormone action, binding of 125I-labeled human growth hormone to enzymatically isolated rat hepatocytes was studied. Specific binding was shown with hepatocytes from both male and female animals. There was a single class of receptors for human growth hormone on cells from males (affinity constant, Ka = 1.16 x 10(9) liters/mole; sites per cell, q = 6200). In males, bovine growth hormone was almost as potent as human growth hormone in displacing bound 125I-labeled human growth hormone, while ovine prolactin was about 1000 times less potent. Cells from female rats bound more 125I-labeled human growth hormone than cells from males. The cells from females contained at least two classes of receptors for human growth hormone. The receptor of highest affinity had the same affinity for human growth hormone as the single receptor found in males (Ka = 0.96 x 10(9) liters/mole). However, there were three to four times as many of these receptors per cell in females (q = 21,000). In females, bovine growth hormone and ovine prolactin were both about 20 times less potent than human growth hormone. Treatment of male rats with estrone produced cells that show the same binding characteristics as females. These results indicate that human growth hormone binds to a somatogenic receptor in hepatocytes from male rats. In females and estrogen-treated males, the receptors that bind human growth hormone recognize lactogenic as well as somatogenic properties. This suggests that the lactogenic and growth-promoting effects of human growth hormone in the rat are mediated by different receptors.
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PMID:Sex differences in binding of human growth hormone to isolated rat hepatocytes. 17 58

Investigations on various kinds of biological actions of a newly purified hypothalamic tridecapeptide, neurotensin, were performed both in vivo and in vitro by utilizing experimental animal models. The effect of neurotensin on pituitary gonadotropin release was studied in ovariectomized estrogen-progesterone-treated rats by the measurement of serum levels of luteinizing hormone (LH), follicle stimulating hormone (FSH) and prolactin (PRL) in radioimmunoassays. Neurotensin (340 mg/100 g BW) significantly increased serum LH and FSH 30 minutes after an intravenous injection (p smaller than 0.05) and lowered serum prolactin concentrations significantly (p less than 0.025). Bradykinin and substance P showed on significant effect on serum LH and FSH release. Intraperitoneal or intravenous administration of 0.5 n.mole neurotensin lowered blood pressure in intact mature rats from the range of 90 approximately 100 mmHg to 50 approximately 60 mmHg; however, tachyphylaxis was observed after repeated injections of the same dose of this peptide. Neurotensin was as potent as bradykinin in inducing rat duodenum relaxation and guinea pig ileum contraction in vitro. Theses effects on neurotensin and bradykinin on the intestines were not inhibited by the pre-treatment of phentolamine, propranolol, methysergide and pyribenzamine. Bradykinin induced contractions of the uterus in proestrous rats, but neurotensin induced no marked contraction. These results suggest that neurotensin in not hypothalamic releasing or inhibiting factor but possess the nature of kinin.
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PMID:[A study on the biological action of hypothalamic tridecapeptide, neurotensin (author's transl)]. 43 7

This study was carried out as a step toward clarifying the hormone responsiveness of mammary tumors in the F1 hybrid mice of the GR/A and SHN strains. Mammary tumors in SHN mice are pregnancy-independent while mammary tumors of GR/A mice are pregnancy-dependent. Females of each strain were mated with males of the other strain to produce F1 hybrids. They were subjected to forced breeding without subsequent lactation. Only animals with palpable mammary tumors during 2nd and 4th pregnancies were used. Mice received sc injections of several hormones, singly or in combination, daily from 1 day after parturition, i.e., .5 mcg of estradiol benzoate (EB) and of 100 mcg human placental lactogen (HPL). The dose of progesterone (P) before parturition was 100 mcg and after parturition 1 mg. A group received grafts of isologous pituitary glands under kidney capsules (3 AP) during Days 12-34 of pregnancy. 1 day after parturition each mouse was given a single ip injection of 50 micro Ci tritiated-thymidine (tritiated-TdR; 5 Cim/mole) along with the last injection of hormones. Animals were killed 2 hours later. Cyclic SHN mice with mammary tumors received tritiated-TdR, after 2 daily injections of hormones, for 3 days, or after 7-8 days of 3AP. The index of DNA synthesis was determined by a liquid scintillation countermeasuring tritiated-TdR incorporated with DNA. Some of the mice were bled 1 day after parturition and plasma prolactin assayed. Hormone responsiveness was similar among GR/A and both F1 hybrids in either normal or neoplastic glands. DNA synthesis of mammary tumors did not respond to any hormone used but normal glands were stimulated by the hormones. EB injection or 3AP did not alter tritiated-TdR incorporation. HPL injection stimulated DNA synthesis of normal glands but not of tumors. P significantly increased the synthesis of both normal and neoplastic mammary glands. EB and HPL injected with P also significantly promoted DNA synthesis of tumors, but did not increase synthesis in normal glands cuased by P. Plasma prolactin levels were significantly increased by EB injection or by 3AP but were not altered by P. In SHN mice DNA synthesis in mammary tumors was not altered by any hormone treatment but synthesis in normal glands was increased by all treatments. Findings suggest that the hormone-responsiveness of pregnancy-dependent mammary tumors in GR/A and its F1 hybrids is different from some other mammary tumors in mice and rats. Progesterone was more important than prolactin or estrogen for tumor growth. Although EB injection was without effect, intact mice were used so some endogenous estrogen may have participated in the effect. While hormone responsiveness of mammary tumors was different between GR/A and SHN mice, the tumors in both hybrids (BR/A with SHN F1 and SHN with GR/A F1) showed responses quite similar to those of tumors of GR/A mice. This suggests the dominance of the GR/A genotype over the SHN genotype for determining the biological characteristics of mammary tumors.
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PMID:Importance of progesterone in DNA synthesis of pregnancy-dependent mammary tumors in mice. 98 72

The role of prolactin and of estradiol and progesterone in the control of the biosynthetic and secretory activity of TIDA neurons has been investigated in the following animal models: young female rats, aged female rats, and young male rats. The indices of TIDA neuronal function employed were a) mass of TH in neurites in the ME, b) total in situ activity of TH in the ME, c) in situ molar activity of TH in the ME, and d) secretion of dopamine into hypophysial portal blood. It was found that prolactin in high concentration in the circulation and in the CSF had little, if any, effect on the mass of TH in the ME. However, a high concentration of prolactin in either the circulation or in the CSF stimulated significantly the in situ TH activity in the ME whether expressed in terms of total activity per ME or activity per mole of TH. The stimulation of TH activity with prolactin was prevented by immunoneutralization of circulating prolactin. A high concentration of prolactin in the CSF was as effective in stimulating TH activity in the ME of rats with intact pituitary glands as in hypophysectomized rats. In addition to prolactin, treatment of animals with intact pituitaries with a combination of estradiol and progesterone markedly stimulated the total in situ activity of TH of the ME as well as the in situ molar activity of TH of the ME, but neither estradiol nor progesterone alone had an effect on TH activity. Hypophysectomy abolished the stimulatory action of estradiol and progesterone on TH activity of the ME. In addition to the in situ activity of TH in the ME, estradiol-progesterone treatment stimulated the secretion of dopamine into hypophysial portal blood. Neither estradiol nor progesterone alone affected dopamine secretion by TIDA neurons. We conclude that exposure to high concentrations of prolactin or to both estradiol and progesterone stimulate the biosynthetic and secretory activity of TIDA neurons. These hormones are effective in old rats and well as young rats and in males as well as females.
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PMID:The tuberoinfundibular dopaminergic neurons of the brain: hormonal regulation. 223 20

To determine the role of arginine vasopressin (AVP) in stress-induced release of anterior pituitary hormones, AVP antiserum or normal rabbit serum (NRS) was micro-injected into the 3rd ventricle of freely-moving, ovariectomized (OVX) female rats. A single 3 microliter injection was given, and 24 hours later, the injection was repeated 30 min prior to application of ether stress for 1 min. Although AVP antiserum had no effect on basal plasma ACTH concentrations, the elevation of plasma ACTH induced by ether stress was lowered significantly. Plasma LH tended to increase following ether stress but not significantly so; however, plasma LH following stress was significantly lower in the AVP antiserum-treated group than in the group pre-treated with NRS. Ether stress lowered plasma growth hormone (GH) levels and this lowering was slightly but significantly antagonized by AVP antiserum. Ether stress also elevated plasma prolactin (Prl) levels but these changes were not significantly modified by the antiserum. To evaluate any direct action of AVP on pituitary hormone secretion, the peptide was incubated with dispersed anterior pituitary cells for 2 hours. A dose-related release of ACTH occurred in doses ranging from 10 ng (10 p mole)-10 micrograms/tube, but there was no effect of AVP on release of LH. The release of other anterior pituitary hormones was also not affected except for a significant stimulation of TSH release at a high dose of AVP. The results indicate that AVP is involved in induction of ACTH and LH release during stress. The inhibitory action of the AVP antiserum on ACTH release may be mediated intrahypothalamically by blocking the stimulatory action of AVP on corticotropin-releasing factor (CRF) neurons and/or also in part by direct blockade of the stimulatory action of vasopressin on the pituitary. The effects of vasopressin on LH release are presumably brought about by blockade of a stimulatory action of AVP on the LHRH neuronal terminals.
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PMID:Role of arginine vasopressin in control of ACTH and LH release during stress. 298 9

Glucocorticosteroids stimulate growth hormone (GH) synthesis and inhibit prolactin (PRL) synthesis and cell growth in cultured GH3 cells, a clonal cell strain derived from a rat pituitary tumour. This model system was used to study the mechanism by which glucocorticosteroids enter target cells. The cellular uptake of [3H]dexamethasone was temperature dependent and was further inhibited by addition of an excess amount of cold dexamethasone. Half maximal uptake was obtained after about 5 min at 37 degrees C. The initial rates of [3H]dexamethasone uptake were a linear function of the extracellular hormone concentration. The uptake of [3H]dexamethasone in intact cells studied at different temperatures resulted in linear Arrhenius plots, with a calculated energy of activation of 91.0 kJ x mole-1 x degree-1. Scatchard analysis of specifically cell bound [3H]dexamethasone at equilibrium (0 degrees C) showed a straight line with a calculated dissociation constant (Kd) of 1.6 x 10(-9) M and a maximal uptake of 180 x 10(-15) mole/mg cell protein. Specific binding of [3H]dexamethasone to cytosol proteins could only be demonstrated at 0 degrees C. These results indicate that [3H]dexamethasone diffuses passively into the cell, and binds to specific receptors in an energy dependent way.
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PMID:The mechanism of [3H]dexamethasone uptake into prolactin producing rat pituitary cells (GH3 cells) in culture. 369 11

LH and FSH of cerebrospinal fluid (CSF) and serum were radioimmunologically measured. Samples were obtained simultaneously from 116 subjects of the following groups: A. 22 patients with non-endocrine diseases, B. 18 patients with cranial diabetes insipidus (DI) of whom 4 with metastatic carcinomas, C. 5 patients with primary empty sella syndrome, D. one with hydatiform mole, and E. 70 patients with pituitary adenomas, i.e. growth hormone--or prolactin-secreting or "non-secreting" adenomas, of whom 38 patients with invasive and 32 with enclosed adenomas. LH and FSH are normal constituents of CSF and their CSF levels poorly correlates with the serum ones (LH r = 0.477 p less than 0.01). Enclosed adenomas with SSE showed low levels of LH in CSF. High CSF-gonadotropins concentrations (above 4.0 mIU/ml) with a low serum/CSF ratio (below 3) was frequently, but not constantly found in patients with invasive adenomas and are not indicative per se of this diagnosis. Some patients with brain metastasis from breast carcinoma and DI, or with non-tumoral diseases and DI showed similar high patterns of CSF gonadotropins though the serum levels were within normal range. This suggests that local vascular mechanisms, including the retrograde circulation of gonadotropins from the pituitary to the hypothalamus, influence the blood-brain barrier much more than the release of gonadotropins into the systemic blood circulation.
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PMID:LH and FSH in human cerebrospinal fluid. 391 6

Suppression of puerperal lactation by a potent serotonin antagonist, metergoline was studied in 33 puerperal women, i.e., abortion after sixteen weeks of gestation 6, premature labor 13, labor at term 13, and hydatiform mole 1. The drug was administered orally at a dose of 4 mg bid for 5 days to 26 subjects, starting within one week from delivery (group A). The remaining 7 subjects received 4 mg of metergoline bid for 7 days after more than 2 weeks from delivery (group B). Lactation was either rapidly suppressed or prevented in 22 out of the 26 subjects in group A and in all subjects in group B. After the therapy was stopped, rebound phenomena were observed in 4 subjects in group A and in 2 subjects in group B, but a further 5-7 days' treatment with metergoline produced satisfactory results. The mean plasma prolactin levels, studied in 10 subjects in group A at hourly intervals after the first metergoline dose, decreased significantly one hour later (p less than 0.05) and reached the nadir level, 19.9 +/- 2.6% of the mean basal value, 4 hours later. The daily plasma prolactin levels in 9 subjects were significantly lower than those of the control group during metergoline treatment (p less than 0.001). No side effects of metergoline medication were observed. Metergoline for a short course of administration is very effective in the suppression of puerperal lactation. In case of the suppression of lactation after the second week of puerperium, 10-14 days of metergoline treatment is recommended to avoid the rebound phenomena.
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PMID:[Suppression of puerperal lactation by metergoline]. 682 65


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