Wyniki wyszukiwania

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Effects of somatostatin-14 and the receptor-specific somatostatin analogs on chromogranin A and alpha-subunit (alpha-SU) release from 'clinically nonfunctioning' pituitary adenoma cells incubated in vitro

100%

Pawlikowski M., Lawnicka H., Pisarek H., Kunert-Radek J., Radek M., Culler M. D.

Journal of Physiology and Pharmacology

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2007

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tom 58

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nr 1

The aim of the study was to examine the effect of somatostatin (SST) and its analogs on the release of chromogranin A (CgA) and alpha-subunit (alpha-SU) from clinically non-functioning pituitary adenomas incubated in vitro. Seven pituitary macroadenomas surgically removed were investigated. All of the tumors were diagnosed before surgery as non-functioning, but they expressed either gonadotropins or their subunits as detected by immunohistochemistry. Two tumors additionally expressed prolactin and growth hormone. All adenomas also expressed chromogranin A (CgA) and at least 3 of 5 subtypes of somatostatin receptors. The cells isolated from the examined tumors were exposed in vitro to either native SST-14 or the following receptor-specific SST analogs : BIM-23926 (agonist of sst1 receptor), BIM-23120 (agonist of sst2 receptor), BIM-23206 (agonist of sst5 receptor) and BIM23A387 (somatostatin/dopamine chimera). The concentration of CgA was measured by means of ELISA method and of alpha-SU was measured by an immunoradiometric method. It was found that the exposure on SST-14 resulted in the decrease of CgA and alpha-SU release from tumor cells in majority of samples, and the effect on CgA was positively correlated with the expression of sst3 and also with the sst2A/sst2B expressions ratio. The inhibitory effect of SST-14 on CgA and alpha-SU seems also to correlate negatively with the expression of sst2B. CgA inhibition also correlates positively with sst5 expression. Among the other compounds studied, only the sst2 agonist decreased the release in all the investigated samples. The remaining substances (agonists of sst1 and sst5 and SST/DA chimera) produced the divergent changes (increased or decreased release, depending on the sample). The data suggest that the inhibition of CgA (and possibly of alpha-SU) release by SST is mediated via subtypes sst2A, sst3 and sst5, whereas sst2B subtype may induce the opposite effect.

2

The cloning and characterization of Tetrahymena pyriformis translation elongation factor 1B alpha and gamma subunits

100%

Jonusiene V., Sasnauskiene S., Juodka B.

Cellular and Molecular Biology Letters

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2005

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tom 10

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nr 4

3

Rational design of new competitive inhibitors of human CK2 activity

84%

Moro S., Ben D. D., Zagotto G., Meggio F., Sarno S., Pinna L. A.

Cellular and Molecular Biology Letters

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2003

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tom 08

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nr 2A

4

Isolation of a cDNA encoding the alpha-subunit of CaaX-prenyltransferases from Catharanthus roseus and the expression of the active recombinant protein farnesyltransferase

84%

Courdavault V., Burlat V., St-Pierre B., Gantet P., Giglioli-Guivarc'h N.

Cellular and Molecular Biology Letters

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2005

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tom 10

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nr 4

5

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Local effect of progesterone infusion into ovarian artery on activin A and inhibin alpha-subunit secretion during the middle luteal phase in gilts

67%

Wasowska B., Stefanczyk-Krzymowska S.

Polish Journal of Veterinary Sciences

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2010

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tom 13

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nr 1

97-104

The present study was undertaken to elucidate whether an increased, but physiological, amount of progesterone (P4) supplied to the porcine corpus luteum affects luteal secretion of activin A and inhibin a-subunit (Inha) in freely moving gilts. On day 9 of the estrous cycle (EC), both ovarian arteries and both ovarian veins of gilts (n=5) were cannulated. Progesterone was infused into the right ovarian arteries in gilts on days 10, 11 and 12 of the EC at a rate adequate to its physiological retrograde transfer found during the middle luteal phase of the EC. The P4 infusion rate was 0.62 μg/min (day 10), 2x0.62 μg/min (day 11) and 3x0.62 μg/min (day 12). The left ovarian arteries were infused with saline (control). Blood samples were collected from both ovarian veins on days 10-12 of the EC before and after P4 or saline infusion. The mean plasma activin A level in the ovarian vein ipsilateral to the P4-infused ovary was higher (PcO.OOOl) on days 10-12 of the EC than this found in the contralateral ovarian vein. The level of activin A in the ovarian vein ipsilataral to the infusion of P4 was higher on days 11 (PcO.Ol) and 12 (P<0.0001) and tended to be higher (P<0.07) on day 10 of the EC than this in contralateral ovarian vein. The level of Inha in the ovarian vein ipsilateral to the P4-infused ovary on days 10-12 of the EC was not significantly different (P>0.05) than this found in the contralateral ovarian vein. The results of the present study indicate that a local elevation of P4 concentration in blood supplying the ovary during the middle luteal phase of the porcine EC affects ovarian secretion of activin A. The effect of P4 on the secretion of activin A suggested the existence of a short regulatory loop of a positive feedback between P4 being retrogradely transferred into the ovary and the secretion of this peptide.

6

High light induced accumulation of two isoforms of the CF1 alpha-subunit in mesophyll and bundle sheath chloroplasts of C4 plants

67%

Romanowska E., Powikrowska M., Zienkiewicz M., Drozak A., Pokorska B.

Acta Biochimica Polonica

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2008

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tom 55

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nr 1

The effect of light irradiance on the amount of ATP synthase α-subunit in mesophyll (M) and bundle sheath (BS) chloroplasts of C4 species such as maize (Zea mays L., type NADP-ME), millet (Panicum miliaceum, type NAD-ME) and guinea grass (Panicum maximum, type PEP-CK) was investigated in plants grown under high, moderate and low light intensities equal to 800, 350 and 50 μmol photons m -2 s -1, respectively. The results demonstrate that α-subunit of ATP synthase in both M and BS chloroplasts is altered by light intensity, but differently in the investigated species. Moreover, we identified two isoforms of the CF1 α-subunit, called α and ά. The CF1 α-subunit was the major isoform and was present in all light conditions, whereas ά was the minor isoform in low light. A strong increase in the level of the ά-subunit in maize mesophyll and bundle sheath thylakoids was observed after 50 h of high light treatment. The α and ά-subunits from investigated C4 species displayed apparent molecular masses of 64 and 67 kDa, respectively, on SDS/PAGE. The presence of the ά-subunit of ATPase was confirmed in isolated CF1 complex, where it was recognized by antisera to the α-subunit. The N-terminal sequence of ά-subunit is nearly identical to that of α. Our results indicate that both isoforms coexist in M and BS chloroplasts during plant growth at all irradiances. We suggest the existence in M and BS chloroplasts of C4 plants of a mechanism(s) regulating the ATPase composition in response to light irradiance. Accumulation of the ά isoform may have a protective role under high light stress against over protonation of the thylakoid lumen and photooxidative damage of PSII.

Ograniczanie wyników

Effects of somatostatin-14 and the receptor-specific somatostatin analogs on chromogranin A and alpha-subunit (alpha-SU) release from 'clinically nonfunctioning' pituitary adenoma cells incubated in vitro

The cloning and characterization of Tetrahymena pyriformis translation elongation factor 1B alpha and gamma subunits

Rational design of new competitive inhibitors of human CK2 activity

Isolation of a cDNA encoding the alpha-subunit of CaaX-prenyltransferases from Catharanthus roseus and the expression of the active recombinant protein farnesyltransferase

Local effect of progesterone infusion into ovarian artery on activin A and inhibin alpha-subunit secretion during the middle luteal phase in gilts

High light induced accumulation of two isoforms of the CF1 alpha-subunit in mesophyll and bundle sheath chloroplasts of C4 plants