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

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

1. The effect of somatostatin and eighteen somatostatin analogues on pentagastrin-stimulated gastric acid and pepsin secretion was investigated in the conscious vagotomized cat prepared with chronic gastric fistulae. The majority of the analogues are peptides where D-amino acids are incorporated into the molecule instead of the natural L-isomers. 2. The ID50 for cyclic-somatostatin inhibition of near-maximal gastric acid secretion stimulated by pentagastrin 8 microgram kg-1 hr-1 was found to be 1.29 +/- 0.13 n-mole kg-1 hr-1. Pentagastrin-stimulated pepsin secretion had a lower threshold to somatostatin inhibition than did acid secretion. 3. D-Phe6, D-Phe7, D-Thr10, D-Thr12 and D-Phe6-D-Trp8 analogues all show low biological activity against the secretion of gastric acid and pepsin, growth hormone, insulin and glucagon. None of these analogues are antagonists of the cyclic-somatostatin inhibition of gastric secretion, suggesting that they have low affinity for this somatostatin receptor. 4. The analogues under investigation show parallel changes in activity against gastric and growth hormone secretion, suggesting a similarity between the gastric and growth hormone receptors for somatostatin. 5. D-Cys14 analogues are equipotent with or have a greater potency than cyclic-simatostatin in inhibiting the secretion of gastric acid, growth hormone and glucagon but show low insulin inhibiting activity.
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PMID:Structure-activity relationships of eighteen somatostatin analogues on gastric secretion. 34 35

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

As a first step in our study of structure-function relationships among primate and non-primate growth hormones, human growth hormone (hGH) was subjected to the limited digestive activity of human plasmin. The lyophilized whole digest, containing less than 2% of unchanged hormone, had an average of 2.3 new amino-terminal groups per mole. The digest had the same potency as the native hormone (a) in causing weight gain in hypophysectomized rats; (b) in stimulating somatomedin production in hypophysectomized rats; (c) in stimulating upake of [(3)H]leucine into isolated diaphragm of hypophysectomized rats; (d) in accelerating transport of [(14)C]alpha-aminoisobutyric acid into isolated diaphragm of hypophysectomized rats; (e) in stimulating uptake of [3-0-methyl-(14)C]glucose by isolated adipose tissue of hypophysectomized rats; (f) in accelerating conversion of [(14)C]glucose to (14)CO(2) by isolated epididymal adipose tissue of hypophysectomized rats. The digest also caused glucosuria in partially pancreatectomized rats treated with dexamethasone. These metabolic actions of plasmin-digested hGH in the array of animal tests were confirmed by comparable effects elicited in 11 human subjects (nine pituitary-deficient children and adolescents and two nondeficient adults). A single injection of the plasmin digest caused an increase in plasma free fatty acids and a fall in plasma amino acids. Seven daily injections caused positive balances of nitrogen, phosphorous, sodium, and potassium, gain in body weight, and in two of three subjects impairment of glucose tolerance. The potency of the plasmin digest in producing these metabolic effects in man was comparable to that of native hGH.Thus, 2-3 bonds in the hGH molecule can be cleaved by plasmin without impairing the hormone's growthpromoting, anabolic, diabetogenic, and adipokinetic actions for rat and man.
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PMID:Metabolic effects of plasmin digests of human growth hormone in the rat and man. 427 Jun 45

The purpose of this study was to confirm the relationship between cyclic AMP(cAMP) level in plasma and changes of hormones concentrations in blood, during and after physical exercise. The results were as follows: At rest, plasma cAMP were 23.1 p mole/ml on the average and decreased after glucose loading. The level in plasma increased in proportion to the intensity of exercises. Under the 50% condition of the maximal intensity, cAMP level in plasma was about 40 p mole/ml and the contents of both thyroxine and growth hormone in serum clearly increased. And, under the 70% of the maximal, the contents of both adrenaline and noradrenaline in serum as well as that of cAMP in plasma increased. Plasma cAMP level also increased by prolongation of exercise (ca 45 p mole/ml). And when exercise lasted over 1.5 hrs, plasma glucagon level began to rise. The effect of carbohydrate load to lower the levels of plasma cAMP were also found during physical exercise. These results suggested that the cAMP level in plasma was affected, not only by the some regulating factors of glycolytic activities such as adrenaline and glucagon, but also by the production of thyroxine and growth hormone at the onset of exercise.
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PMID:[Effect of exercise on plasma cyclic AMP]. 609 99

It has been shown that the extent of methylation of cytosine in vertebrate DNA is inversely correlated with gene expression. We studied cytosine methylation in and around the homologous human growth hormone (GH) and chorionic somatomammotropin (CS) genes to determine if these genes are undermethylated in DNA from tissues in which they are expressed (pituitary and placenta, respectively) compared to other tissues. Hpa II and Hha I (which cleave only unmethylated 5' CCGG 3' and 5' GCGC 3' respectively) and Msp I (which cleaves CCGG and CmeCGG) were used to digest DNA samples followed by gel electrophoresis, Southern transfer and hybridization with a GH cDNA probe. The extent of methylation of Hpa II and Hha I sites in the GH and CS genes was leukocyte much greater than pituitary greater than placenta = hydatidiform mole. Taken as a whole, our data support the hypothesis that undermethylation is a necessary but not sufficient condition for gene expression since placental and pituitary DNAs are less methylated than leukocyte DNA in this region. However, the correlation between gene expression and undermethylation is imperfect since (1) hydatiform mole DNA has a very similar methylation pattern compared to placental DNA even though moles make little or no CS and (2) the level of methylation of the GH gene compared to the CS gene does not vary in a tissue-specific manner.
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PMID:Relative levels of methylation in human growth hormone and chorionic somatomammotropin genes in expressing and non-expressing tissues. 628 1

Iodinated bovine growth hormone, containing no more than 1 g-atom of iodine per mole of hormone is generally used as a tracer in studies related to the action and metabolism of the hormone. This derivative was tested in different biological and immunological systems in which the hormone is known to be active. The iodinated derivative was almost indistinguishable in its properties from the native hormone when it was examined by the following criteria: body growth promoting activity, rat liver uptake in vivo, binding to rabbit liver microsomes and primary antigen-antibody interactions. Micro-complement fixation experiments suggested that the iodination produces minor alterations in the affinity of some antigenic determinants.
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PMID:Biological and immunological characterization of iodinated bovine growth hormone. 628 84


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