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)

The administration of monosodium-L-glutamate (MSG) during the neonatal period is known to result in central nervous system lesions in the arcuate nucleus of the hypothalamus and the retina. Rodents so treated exhibit behavioral deficts and endocrinopathies including obesity, hypogonadism, hypothyroidism, pituitary atrophy, tail automutilation and diminished locomotor activity. Assessment of endocrine status revealed normal serum levels of glucagon, thyroid-stimulating hormone and luteinizing hormone, and diminished levels of thyroid hormones and growth hormone in MSG-treated rats. Prolactin levels were elevated in the glutamate-treated male rats. Within the brain hypothalamic levels of thyrotropin-releasing hormone, luteinizing hormone-releasing hormone, and somatostatin were unchanged. Measurement of neurotransmitters and neurotransmitter-related enzymes in individual hypothalamic nuclei derived from MSG-treated rats revealed normal levels of norepinephrine, serotonin and glutamic acid decarboxylase, but reduced levels of choline acetyltransferase and dopamine in the arcuate nucleus and median eminence. Histochemical methods for visualization of dopamine and acetylcholinesterase in the mediobasal hypothalamus confirmed these findings. The MSG-treated animals exhibited a normal diurnal rhythm of pineal serotonin N-acetyltransferase activity. These data indicate that the MSG-induced endocrine deficiency syndrome results at least partly from destruction of cholinergic and dopamingeric tuberoinfundibular systems in the hypothalamus.
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PMID:Models of neuroendocrine regulation: use of monosodium glutamate as an investigational tool. 3 35

The pineal contains a large number of classical transmitters and neuropeptides. Some of these neurochemicals are involved in the regulation of serotonin N-acetyltransferase (NAT) activity and hence in melatonin synthesis. Synaptic ribbons present in the pineal gland also exhibit a numerical day/night rhythm parallel to that of NAT activity. There is scarcity of information regarding the regulation of synaptic ribbon (SR) numbers. In the present study, we have investigated in vitro effects of a number of classical neurotransmitters and neuropeptides. NAT activity was used to monitor melatonin synthesis under the experimental conditions used. Norepinephrine (NE), Delta sleep-inducing peptide (DSIP), vasoactive intestinal polypeptide (VIP), adenosine and N-acetyl-asp-glu (NAAG) significantly increased NAT activity in rat pineal. DSIP and VIP also increase the stimulatory effect of NE on NAT activity. These neurochemicals had no effect on SR numbers. Gamma aminobutyric acid (GABA), serotonin and taurine affected neither NAT activity nor SR. Somatostatin increased SR numbers significantly, without having any effect on NAT activity. The effect of somatostatin is regarded to be pharmacologic, since rather high dosages (10(-4) M) were required to obtain a significant effect. Although somatostatin is present in the pineal and may change rhythmically, the inconsistency of the day/night rhythmicity and the lack of such a rhythm in female rats and male gerbils speaks against an important physiological role of somatostatin in regulating SR numbers.
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PMID:In vitro effects of putative neurotransmitters on synaptic ribbon numbers and N-acetyltransferase activity in the rat pineal gland. 135 54

Somatostatin is a potent antiproliferative signal in both tumoral and normal mammalian cells, and altered somatostatin receptor (sst) expression is associated with carcinogenesis in human tissues. In this study, two normal and three tumoral human pineal glands were analyzed using the reverse transcriptase-polymerase chain reaction (RT-PCR) for the presence of mRNA coding for the five different somatostatin receptors (sst1-sst5). Pineal parenchymal tumor (PPT) differentiation was confirmed by immunohistochemical detection of neuroendocrine markers (synaptophysin, neurofilaments, and chromogranin A). The presence of mRNA coding for c-myc, a proto-oncogene, and for tryptophan hydroxylase (TPOH), serotonin N-acetyltransferase (NAT), and hydroxyindole-O-methyltransferase (HIOMT), enzymes of the melatonin pathway, was also analyzed by RT-PCR. Only the tumoral tissues contained c-myc mRNA. All five tissues contained TPOH, NAT, and HIOMT mRNA, the levels of HIOMT mRNA being lower in PPT than in the normal pineal gland, suggesting that PPT retain the ability to synthesize melatonin. All tissues contained sst1, sst2, and sst3 transcripts, but not sst4, while small amounts of sst5 mRNA were only found in normal pineal glands. Real-time PCR, performed only with the most abundant subtpe sst2, evidenced an about sixfold higher level in in normal pineal glands. These results demonstrate the presence of somatostatin receptors in the human pineal gland, as described in other species, and point to a differential expression of the sst2 and sst5 subtypes associated with carcinogenesis.
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PMID:Differential somatostatin receptor subtype expression in human normal pineal gland and pineal parenchymal tumors. 1270 86