Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P61278 (somatostatin)
 22,083 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In a 51-year-old man with hyperthyroidism, elevated plasma TSH levels, and evidence of pituitary tumor, plasma TSH levels decreased from a mean basal value of 11 muU/ml to 6 mu/u/ml during the infusion of 200 mug of somatostatin in 60 min. Thyrotropin releasing factor failed to increase plasma TSH levels. T3 administration failed to supress significantly the elevated thyroid 131I uptake. During T3 administration plasma TSH levels showed a downtrend but were not clearly suppressed. These findings are discussed in light of the pertinent literature.
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PMID:Hyperthyroidism with elevated plasma TSH levels and pituitary tumor: study with somatostatin. 82 3

The physiologic relationships of plasma TSH, T4 and T3 levels measured every 20 min in seven healthy young men and one healthy young woman have been investigated. A nocturnal TSH surge was observed in all subjects on both nights of the 36-48 h baseline observation period. In males the maximum plasma TSH value occurred at 2300 h. The mean peak TSH level was 2.0 +/- 0.3 (se) muU/ml compared with a mean of 1.3 +/- 0.9 muU/ml for the entire baseline records of the 8 subjects. The effect of iv infusion of 32-1000 mug of somatostatin (SRIF) for 1 1/2-3 h was investigated in four of the male subjects during 2 or 4 consecutive nights following the control period. Temporal relationships between the hormonal fluctuations observed throughout the control period and during the nights of SRIF infusion were investigated using time series analysis and Student's t test. Rapid fluctuations of plasma T4 and T3 concentration were noted, even when corrected for changes in total protein concentration, with an average coefficient of variation of 10% for T3 and 12% for T4. No increment of plasma T4 or T3 followed the nocturnal TSH surge nor were the rapid fluctuations of the thyroid hormones altered by the TSH surge. SRIF infusion commencing at 2300 h suppressed the elevated TSH levels (P is less than 0.01) while similar infusions begun at 2100 h blocked the expected nocturnal TSH rise observed during control periods in male subjects. Plasma T4 and T3 levels were not significantly affected by the administration of SRIF. The relationship of the rapid plasma T4 and T3 variations to postural changes was investigated in four euthyroid male subjects. Serum levels of TSH, T4 and T3 and total protein were determined at 15 min intervals while postural changes were carefully monitored. The ratios of T4 and T3 to total protein were relatively stable (3-4% coefficient of variation) when the subjects were kept in a supine and motionless position. A 50 mug bolus infusion of T4 raised the basal T4 level by only 1-2 mug/dl. The data suggest that short-term fluctuation of plasma T4 and T3 result from changes in protein concentration due to hemodynamic responses to alteration of posture and physical activity and not to pulsatile secretion of T4 and T3.
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PMID:Plasma thyrotropin, thyroxine, and triiodothyronine relationships in man. 95 41

The effect of hypophysectomy on the hypothalamic somatostatin content was examined in rats. Somatostatin content in the acid extract of the pituitary stalk and the median eminence tissue (SME) was measured by specific radioimmunoassay. In young male rats, the mean somatostatin content in SME was 63.9+/-5.0 ng. Two weeks after hypophysectomy, it was reduced significantly to 34.4+/-3.3 ng. The result may indicate that the elimination of feedback actions of GH and/or TSH on the hypothalamus led to the decreased synthesis and/or the release of somatostatin. However, the possibility that structural changes in the pituitary stalk and the median eminence tissue ensued after hypophysectomy resulted in the depletion of somatostatin cannot be ruled out.
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PMID:Effect of hypophysectomy on hypothalamic somatostatin content in rats. 100 97

One male rat pituitary placed in a chamber was perifused with cyclic somatostatin (GIF) for 30 min. Either 160 nM or 1.6 muM GIF caused a decrease in the release of GH. The release of TSH was also decreased by 160 nM GIF, and paradoxically increased by 1.6 muM GIF. Increasing the dose of GIF to 16 muM resulted in an abrupt rise in the release of both GH and TSH during the perfusion; then the level of GH decreased to the nadir level followed by an elevation above the base line, while that of TSH promptly fell back toward the base line. The release of PRL was not clearly affected by 16 muM GIF. [Tyr8]-GIF did not have such stimulatory activities. These results indicate that GIF not only inhibits the release of GH and TSH, but also stimulates that of GH and TSH in this system, depending on its dose.
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PMID:Variety of GH and TSH responses to somatostatin in perfused rat pituitaries in vitro. 102 27

The synthetic linear tetradekapeptide somatostatin (growth-hormone release inhibitory hormone: GHRIH) inhibits the liberation of growth hormone in normal persons in the insulin hypoglycaemia test without influencing the rise of cortisol and prolactin, while the concentrations of LH, FSH and TSH remain unchanged. In patients with florid acromegaly there occurs during administration of GHRIH a marked fall in the raised STH level without influencing the basal level of the other anterior-pituitary hormones. As a further effect there is suppression of the insulin level. The somatostatin at present available has a very short biological half-life and in its present form is, therefore, without therapeutic importance.
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PMID:[The effect of synthetic somatostatin in normal and acromegalic males]. 109 Apr 28

Somatostatin, a growth hormone inhibiting factor (GHIF), was infused into 8 patients with primary hypothyroidism at a dosage of 1000 mug for 105 min. GHIF caused a suppression of TSH levels from 42.6 to 76.9% of preinfusion levels with a mean nadir of 65.0 +/- 4.0%;(mean +/- SEM).
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PMID:The effect of somatostatin on TSH levels in patients with primary hypothyroidism. 120 95

Somatostatin, a peptide isolated from ovine hypothalami, prevents growth hormone secretion in vivo and in vitro. Moreover, somatostatin interferes with the secretion of various other hormones: TSH insulin, glucagon, gastrin, VIP and GIP. Under certain conditions a blunting effect on the secretion of prolactin and ACTH can be demonstrated.
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PMID:[Somatostatin -- a review (author's transl)]. 126 5

The aim of the present study was to examine the effects of melatonin (Mel) and of pinealectomy (PX) [in a long-term experiment in vivo - 10 weeks], as well as of Mel and N-acetylserotonin (NAc-5HT) [in experiments ex vivo in vitro and in vitro], on the rat thyroid growth processes. Additionally, the incubations in vitro of rat thyroid lobes with 3H-thymidine, in the presence of TSH, vasoactive intestinal polypeptide (VIP), VIP-antagonist ([4Cl-D-Ph6, Leu17]VIP), somatostatin (SS), all the substances used separately or jointly in combinations, were performed. It was shown that: (a) Mel--administered in late afternoon injections--decreased, while PX increased examined indices of thyroid growth in vivo, (b) Mel--administered in s.c. implanted pellets--reversed the inhibitory effect of Mel injections, (c) in experiments ex vivo in vitro and in vitro, the inhibitory effect of Mel revealed only for the lowest applied dose/concentration of the hormone, (d) NAc-5HT showed no effect, (e) VIP decreased 3H-thymidine incorporation into DNA of thyroid lobes in vitro and enhanced the inhibitory effect of SS on the process in question, (f) VIP-antagonist failed to reverse the inhibitory action of VIP on the thyroid growth.
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PMID:Effects of pineal-derived indolic compounds and of certain neuropeptides on the growth processes in the thyroid gland. 128 26

We evaluated serum alpha-subunit concentrations in 72 patients bearing pituitary adenomas. We conclude that: 1) alpha-subunit hypersecretion is found in all patients with TSH secreting pituitary adenoma (n = 10). Two patients have a predominant secretion of alpha-subunit as compared to TSH secretion. 2) As concerns gonadotropin secreting pituitary adenomas (n = 3), all patient have elevated serum alpha-subunit levels with increased FSH and LT concentrations in 2 cases and 1 case respectively. 3) In prolactinomas (n = 14), alpha-subunit concentrations are not significantly different from that of normal subjects. 4) In 11 acromegalic patients, alpha-subunit hypersecretion is found in 2 patients only with GH-alpha and GH-PRL-alpha secreting pituitary adenomas. 5) Among 34 patients with nonsecreting adenomas, 8 have elevated alpha-subunit concentrations (24%). Positive immunocytochemical staining is found in 70% most often with gonadotropins (55%). Only a few pituitary tumors with positive alpha-subunit immunocytochemical staining have elevated serum alpha-subunit levels. At least, the measurement of basal circulating alpha-subunit levels is very useful in the follow-up of patients with nonsecreting adenomas. In our study, medical treatments including bromocriptine and somatostatin analogues have been found effective in patients with alpha-subunit hypersecretion. Further investigations are necessary to prove if such treatments could control tumoral growth and could prevent recurrences.
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PMID:[Value of alpha subunit assay in pituitary pathology]. 128 29

The thyroid follicular cell requires elevated levels of cAMP for normal growth and optimal expression of the differentiated phenotype. The recent discovery of cAMP-regulated enhancer binding (CREB) proteins prompted us to analyze the possible role of these transcription factors in controlling thyroid cell growth and differentiated phenotype using the FRTL5 thyroid cell line as a model system. FRTL5 cells were stably transfected with an expression vector containing either the gene for wild type CREB (WTCREB) or a dominant negative mutant form of CREB, termed KCREB, which dimerizes with and inactivates endogenous CREB. Transfected clones were found to express the transfected KCREB and WTCREB mRNAs at higher levels than the endogenous CREB mRNA. Transient expression of a somatostatin-chloramphenicol acetyltransferase fusion gene in these clones demonstrated a 60% reduction of cAMP-regulated enhancer-dependent transcriptional activity in the KCREB transfected clones and wild type levels of activity in the WTCREB transfected clones. Parameters of growth (DNA synthesis and growth rate) and differentiation (iodide uptake and thyroglobulin mRNA levels) were then analyzed in the transfected clones. Transfection of WTCREB had no effect on any of the parameters examined in comparison to untransfected cells, presumably because CREB is already constitutively expressed at maximal levels in normal FRTL5 cells. However, cells expressing KCREB showed an 18-40% reduction in TSH-stimulated thymidine incorporation, a 31% increase in the length of the cell cycle, and a 4-fold reduction in TSH-stimulated iodide uptake in comparison with wild type cells or cells tranfected with wild type CREB.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:3',5'-cyclic adenosine monophosphate-regulated enhancer binding (CREB) activity is required for normal growth and differentiated phenotype in the FRTL5 thyroid follicular cell line. 133 55


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