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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
1
|
| pubmed:dateCreated |
1988-1-19
|
| pubmed:abstractText |
In addition to reconstituting immune competence, the thymus gland preparation, thymosin fraction 5 (TSN-5), has recently been shown to stimulate secretion of hormones from the hypothalamic-pituitary adrenal axis in vivo and from pituitary corticotropes in vitro. The purpose of the present study was to investigate the effects of TSN-5 on secretion of immunoreactive beta-endorphin (i beta-E) by mouse corticotropic tumor cells. The release of i beta-E by AtT-20 pituitary tumor cells was increased in a dose-dependent manner by concentrations of 30-600 micrograms/ml of TSN-5, whereas concentrations greater than 1,000 micrograms/ml were increasingly less effective in stimulating secretion. TSN-5 (600 micrograms/ml) significantly stimulated i beta-E release within 7 min; maximal secretory responses (up to 275% of control release) occurred by 4 hr. The secretory response of AtT-20 cells to 600 micrograms/ml TSN-5 (37.9 +/- 2.0 vs. 16.1 +/- 1.0 ng i beta-E/ml/4 hr, mean +/- SE) was similar in magnitude to release evoked by 0.1 microM corticotropin-releasing factor (CRF). Combining TSN-5 and CRF treatments increased secretion of i beta-E to nearly 600% of control levels, an effect greater than an additive influence of the two independent treatments. Whereas CRF treatment reduced the levels of i beta-E in AtT-20 cell extracts after 24-hr treatment by 45% (231.8 +/- 24.7 vs. 417.2 +/- 17.8 ng i beta-E/mg protein, CRF vs. vehicle treatments, respectively), TSN-5 did not significantly alter cellular hormone content. Neither TSN-alpha 1 nor TSN-beta 4, two of the component peptides of TSN-5, affected basal or CRF-stimulated release of i beta-E, indicating that an unidentified constituent(s) is corticotropic.(ABSTRACT TRUNCATED AT 250 WORDS)
|
| pubmed:grant | |
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical | |
| pubmed:status |
MEDLINE
|
| pubmed:issn |
0360-4012
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:volume |
18
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
140-6
|
| pubmed:dateRevised |
2007-11-14
|
| pubmed:meshHeading | |
| pubmed:year |
1987
|
| pubmed:articleTitle |
Thymosin fraction 5 stimulates secretion of immunoreactive beta-endorphin in mouse corticotropic tumor cells.
|
| pubmed:affiliation |
Experimental Therapeutics Branch, National Institute of Neurological and Communicative Disorders and Stroke, Bethesda, Maryland.
|
| pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, Non-U.S. Gov't
|