Intestinal tract, which produces more than fifty kinds of gut peptides, is regarded as the largest endocrine organ. With regard to the gut peptides, a number of studies were focused on their structure, function and the roles in some diseases. The changes in output or distribution of gut peptides in the intestinal tract during development have been largely unknown. This study was aimed to investigate the changes of somatostatin (SST) and somatostatin receptor 2 (SSTR2) in small intestinal and hepatic tissues during the development of macaque. The tissue samples of small intestine, liver or blood samples from peripheral and portal vein of 4 macaques in 6-month fetus, 2-day neonate, 45-day neonate and adult were obtained after anesthetization. The concentrations of SST in blood or tissues of macaques were measured by radioimmunoassay. The distributions of SST in small intestinal or hepatic tissues were visualized by immunohistochemical staining. The expression of SSTR2 was detected by in situ hybridization. SST concentration of intestinal tissue in 6-month-old macaque was (27.3+/-16.6) ng /mg protein and light positive staining of SST was localized in mucosal crypts but negative in muscle layer. The intestinal concentration of SST increased gradually with macaque development and reached to the peak [(120.1+/-35.3) ng /mg protein] in adult. It was significantly higher than that in fetus (P<0.01). Strong positive staining of SST was found in both mucosal crypts and myenteric nerve plexus of adult animal. SSTR2 was obviously expressed in intestinal epithelium of fetus but its expression was greatly reduced in epithelium and was shifted to mucosal crypts when grown to adult. Negative staining of SSTR2 in muscle layer of fetal or neonatal macaque turned to be positive in myenteric nerve plexus of adult. The levels of SST or SSTR2 in liver decreased gradually during development. SST concentrations of small intestinal tissue kept significantly higher than those of hepatic tissues in the macaque developing stages. SST levels of portal vein were also maintained significantly higher than those of peripheral blood in the macaque developing stages. In conclusion, the level of SST and expression of SSTR2 in mucosal crypt increased gradually with macaque development. SST from intestinal tract was quickly degraded in portal vein before entering into liver. SST positive myenteric nerve plexus was visualized only in mature macaque.
Animals ; Animals, Newborn ; Fetus ; Intestine, Small ; metabolism ; Liver ; metabolism ; Macaca mulatta ; growth & development ; metabolism ; Male ; Receptors, Somatostatin ; metabolism ; Somatostatin ; metabolism

Cortical GABAergic inhibitory neurons are composed of three major classes, each expressing parvalbumin (PV), somatostatin (SOM) and 5-hydroxytryptamine receptor 3A (Htr3a), respectively. Htr3a
Animals ; Interneurons/metabolism* ; Mice ; Neurons/metabolism* ; Parvalbumins/metabolism* ; Receptors, Serotonin, 5-HT3/genetics* ; Serotonin ; Somatostatin/metabolism*

Somatostatin (SST) is an inhibitory polypeptide hormone that plays an important role in a variety of biological processes. Somatostatin receptor 2 (SSTR2) is the most widely expressed somatostatin receptor. However, the specific cell types expressing Sstr2 in the tissues have not been investigated. In this study, we detected the expression pattern of SSTR2 protein in mouse at different development stages, including the embryonic 15.5 days and the postnatal 1, 7, 15 days as well as 3 and 6 months, by multicolour immunofluorescence analyses. We found that Sstr2 was expressed in some specific cells types of several tissues, including the neuronal cells and astrocytes in the brain, the mesenchymal cells, the hematopoietic cells, the early hematopoietic stem cells, and the B cells in the bone marrow, the macrophages, the type Ⅱ alveolar epithelial cells, and the airway ciliated cells in the lung, the epithelial cells and the neuronal cells in the intestine, the hair follicle cells, the gastric epithelial cells, the hematopoietic stem cells and the nerve fibre in the spleen, and the tubular epithelial cells in the kidney. This study identified the specific cell types expressing Sstr2 in mouse at different developmental stages, providing new insights into the physiological function of SST and SSTR2 in several cell types.
Mice ; Animals ; Receptors, Somatostatin/metabolism* ; Hematopoietic Stem Cells/metabolism* ; Epithelial Cells

Animals ; Cells, Cultured ; Hepatocytes ; cytology ; metabolism ; Male ; Rats ; Rats, Sprague-Dawley ; Receptors, Somatostatin ; biosynthesis ; classification ; genetics

OBJECTIVESTo observe the expression of somatostatin receptor subtype 2 (SSTR2) mRNA, and investigate the relationship between the expression of SSTR2 mRNA and the expressions of estrogen and progesterone receptors (ERs and PRs) in benign and malignant breast tissues.

METHODSSamples from a total of 23 breast carcinomas, 16 mammary hyperplasias, and 9 mammary fibroadenomas were analyzed. SSTR2 mRNA expression was examined by in situ hybridization using multiphase oligoprobes. ER and PR expressions were detected by immunohistochemical staining. A computerized image analysis system was utilized to estimate the relative content of SSTR2 mRNA.

RESULTSThe rate of expression (87.0%) and relative content (0.47) of SSTR2 mRNA in breast cancer were higher than those in benign breast tissue (64%, 0.26) (P < 0.05). SSTR2 mRNA expression was closely correlated with ER and PR expressions in breast cancer (P < 0.05). SSTR2 mRNA was also positively correlated with ER expression in benign breast tissues.

CONCLUSIONSSSTR2 mRNA expression is higher or in benign breast tissues than in malignant ones. There is a significant positive correlation between SSTR2 mRNA and ER and PR expressions. Combined antiestrogen and somatostatin analogue in treatment of ER-positive breast cancers should be further investigated.

Breast Diseases ; metabolism ; Breast Neoplasms ; chemistry ; Humans ; Immunohistochemistry ; In Situ Hybridization ; RNA, Messenger ; analysis ; Receptors, Estrogen ; analysis ; Receptors, Progesterone ; analysis ; Receptors, Somatostatin ; genetics

BACKGROUNDSomafostatin receptors (SSTRs) have been suggested to involve in mediating the effect of somatostatin on hepatic stellate cells (HSCs) in an activation-dependent way. We, therefore, try to investigate the relationship between expression of SSTRs and activation of rat HSCs.

METHODSHSCs were isolated from rats by in situ perfusion and single-step density gradient centrifugation. SSTR1-5 mRNA levels in the differentiated first passage HSCs were detected by means of a reverse transcription polymerase chain reaction. On the other hand, hepatic fibrosis was induced in adult male Sprague-Dawley rats by carbon tetrachloride intoxication, and the expression of SSTR1-5 in normal as well as fibrotic livers was measured by immunohistochemical staining.

RESULTSSSTR mRNA and SSTR could not be found in freshly isolated rat HSCs or normal rat liver. However, SSTR1-3 mRNA appeared as HSCs became wholly activated, and could also be identified on the membrane of activated HSCs in the perisinusoid space, fibrous septa, etc.

CONCLUSIONThe expression of SSTR1-3 in the rat HSC is closely related to its activation. This may reflect one of the main negative regulation mechanisms in the course of HSC activation.

Animals ; Liver ; cytology ; metabolism ; Liver Cirrhosis ; etiology ; Male ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley ; Receptors, Somatostatin ; genetics

OBJECTIVE: To detect the expression and relationship between somatostatin receptor 2 (SSTR2) and phosphorylated STAT3 (P-STAT3) in human olfactory neuroblastoma (ONB) and adjacent normal olfactory nerve tissue. METHOD: Immunohistochemical (IHC) staining was used to detect the expression of SSTR2 and P-STAT3 in tumor and adjacent normal olfactory nerve tissue from 11 ONB patients. RESULT: SSTR2 was mainly expressed in cell cytoplasm and the expression intensity was significantly stronger in tumor tissues than in adjacent normal tissues (P<0.01). P-STAT3 was mainly expressed in cell nuclear in tumor tissues. No expression was found in adjacent normal tissues. There was a negative correlation between the expression intensity of SSTR2 and P-STAT3 (r(s) = -0.367, P<0.05). CONCLUSION Lower expression of SSTR2 and activation of STAT3 in ONB cells might contribute to the development of ONB.
Adolescent ; Adult ; Esthesioneuroblastoma, Olfactory ; metabolism ; pathology ; Female ; Humans ; Male ; Middle Aged ; Nose Neoplasms ; metabolism ; pathology ; Receptors, Somatostatin ; metabolism ; STAT3 Transcription Factor ; metabolism ; Young Adult

Amino Acid Sequence ; Animals ; Antineoplastic Agents ; chemistry ; metabolism ; pharmacology ; Apoptosis ; drug effects ; Humans ; Molecular Structure ; Neoplasms ; pathology ; prevention & control ; Receptors, Somatostatin ; metabolism ; Somatostatin ; chemistry ; metabolism ; pharmacology ; Structure-Activity Relationship

Recently various peptide receptors which displayed the highest binding affinity and specificity with their peptide ligands by ligand-receptor have been exploited to develop drug delivery system which can directionally deliver drug to targeted cell. It is significant to study and applicate, including targeted drug delivery system mediated by bombesin receptor, somatostatin receptor, SynB3 receptor, LH-RH receptor and other peptide receptor, et al. Several small peptide fragments were selected as carriers radicals combining doxorubicin, 2-pyrrolino-DOX, methotrexate, cis-platinum, and camptothecin to form hybrid cytotoxic analogs. These highly potent cytotoxic analogs have been designed as targeted anti-tumor agents for the treatment and study of various cancers that possess receptors for the carrier peptide.
Animals ; Antineoplastic Agents ; therapeutic use ; Doxorubicin ; analogs & derivatives ; therapeutic use ; Drug Delivery Systems ; Humans ; Neoplasms ; drug therapy ; metabolism ; Oligopeptides ; metabolism ; Pyrroles ; therapeutic use ; Receptors, Bombesin ; metabolism ; Receptors, LHRH ; metabolism ; Receptors, Somatostatin ; metabolism

BACKGROUNDTechnetium-99m or (99m)Tc is widely used for labeling peptide in nuclear medicine. Somatostatin and its analog can inhibit tumor cell growth after binding with its receptor. This research was to study the preclinical effect of a new (99m)Tc-6-hydrazinopyridine-3-carboxylic acid (HYNIC)-depreotide, indirect (99m)Tc labeling of depreotide using HYNIC as a bifunctional chelator.

METHODSThe cyclopeptide, cyclo-[(N-Me) Phe-Tyr-D-Trp-Lys-Val-Hcy], the linear peptide, and [ClCH(2)-CO×b-Dap-Lys- Cys-Lys×amide] were synthesized by Fmoc solid-phase synthesis. The cyclopeptide and the linear peptide were linked by liquid-phase synthesis. The product depreotide was isolated and purified by high performance liquid chromatography and was confirmed by mass spectrography. Depreotide was labeled with (99m)Tc through a direct labeling method, using HYNIC as a bifunctional chelator. Paper chromatography method was used to calculate the labeling rate, and through the comparative analysis selected the best mark conditions. The new (99m)Tc-HYNIC-depreotide was tested by high-performance liquid chromatography (HPLC). The internalization and externalization rates of the new (99m)Tc-HYNIC-depreotide were studied in A549 cells. Furthermore, biodistribution of the radiopeptide was studied in nude mice, bearing tumors from human lung carcinoma cells SPC-A1.

RESULTSThe molecular of synthesize depreotide was 1358, and the purity of it was 95.29%. The labeling efficiency of (99m)Tc-HYNIC-depreotide was highest at pH 6.0 and 15°C, about (70.95 ± 0.84)%. The labeling rate of the new (99m)Tc-HYNIC-depreotide rose to a peak of (20.75 ± 0.48)% at 60 minutes in A549 cells at 37°C and decreased slightly later, while it elevated gradually during the time course at 4°C and 25°C. The internalization rate of the new (99m)Tc-HYNIC-depreotide at 37°C increased gradually and reached the peak of 84.4% in 120 minutes, while the externalization rate of the new (99m)Tc-HYNIC-depreotide was always less than 20%. In mice bearing the experimental SPC-A1 tumor, the new (99m)Tc-HYNIC-depreotide demonstrated a high tumor uptake of (4.05 ± 0.04)% ID/g at 1.5 hpi and remained high ((2.51 ± 0.06)% ID/g) at 4 hpi. The tumor-to-lung activity concentration ratio (T/Lu) was very high for the new (99m)Tc-HYNIC-depreotide at all time points. So did the tumor-to-muscle activity (T/Mu) and tumor-to-blood activity concentration ratios (T/Bl).

CONCLUSIONThe findings suggested that the new (99m)Tc-HYNIC-depreotide might be a promising candidate radiopharmaceutical for imaging somatostatin receptor positive lung cancer.

Animals ; Cell Line, Tumor ; Humans ; Hydrazines ; chemistry ; Lung Neoplasms ; metabolism ; pathology ; Male ; Mice ; Mice, Nude ; Nicotinic Acids ; chemistry ; Receptors, Somatostatin ; metabolism ; Technetium ; chemistry