Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P01189 (beta-endorphin)
 21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of cortisol or adrenocorticotropic hormone (ACTH) on basal and gonadotropin-releasing hormone (GnRH)-induced secretion of luteinizing hormone (LH) was studied in vitro using dispersed pig pituitary cells. Pig pituitary cells were dispersed with collagenase and DNAase and then grown in McCoy's 5a medium containing 10% dextran charcoal-pretreated horse serum and 2.5% fetal calf serum for 3 days. Cells were preincubated with cortisol or ACTH before GnRH was added. When pituitary cells were incubated with 400 micrograms cortisol/ml medium for 6 h or longer, increase basal secretion of LH was observed. However, GnRH-induced LH release was reduced by cortisol. The degree of this reduction was dependent on cortisol, and a concentration of cortisol higher than 100 micrograms/ml was needed. Cortisol also inhibited the 17 beta-estradiol-induced increase in GnRH response. ACTH-(1-24), ACTH-(1-39), or porcine ACTH had no influence on GnRH-induced LH secretion. Our results show that cortisol can act directly on pig pituitary to inhibit both normal and estradiol-sensitized LH responsiveness to GnRH.
 ...
PMID:Effect of cortisol or adrenocorticotropic hormone on luteinizing hormone secretion by pig pituitary cells in vitro. 282 56

In an earlier study on the long-term effects of the pituitary hormone corticotropin (adrenocorticotropin, ACTH), we reported that ACTH promotes the loss of 20-25% of the total actin in isolated rat adrenocortical cells. In a continuation of this work, we report here the purification to near homogeneity of rat adrenal actin. We demonstrate that the protein purified is adrenal actin, and use this actin in the DNAase immunoprecipitation assay of Snabes et al. to confirm our earlier observation of the effect of ACTH on adrenocortical actin. Finally, we describe several changes made in the original protocol of this immunoassay which we believe significantly improve the accuracy of the assay in estimating actin contents in tissue and cell samples.
 ...
PMID:Purification of rat adrenocortical actin and its use in an immunoprecipitation assay to quantitate cellular actin. 352 78

Corticotropin (ACTH) induces a characteristic retraction of rat adrenocortical cells in culture. Densitometric analysis of sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels of cell lysates showed that ACTH induced a 20% decrease in actin content. These results were fully confirmed by quantitation of actin by the DNase 1 inhibition assay. The decrease in actin is hormone-specific, concentration-dependent, and correlates temporally with the morphological change induced by ACTH. The change in actin content and the reorganization of microfilament ultrastructure may together mediate hormone regulation of cell shape at the cytoskeletal level.
 ...
PMID:Regulation of actin in rat adrenocortical cells by corticotropin. 625 51

This study investigated the direct effects of hydrocortisone (HS), corticotropin-releasing factor (CRF), and adrenocorticotropin (ACTH) on basal and gonadotropin-releasing hormone (GnRH)-stimulated secretion of follicle-stimulating hormone (FSH) from dispersed pig pituitary cells in vitro. Pig pituitaries were dispersed into cells with collagenase, DNAase, and hyaluronidase and then cultured in McCoy's 5a medium containing horse serum (10%) and fetal calf serum (2.5%) pretreated with dextran-coated charcoal for 3 days. Cells were preincubated with steroids, CRF, or ACTH before GnRH was added. HS did not affect basal FSH secretion after 72 h of incubation. Treatment of pituitary cells with increasing concentrations (0.001-800 micrograms/ml) of HS for 72 h resulted in a dose-dependent decrease in GnRH-stimulated FSH release. HS pretreatment did not cause a change in cellular FSH content. Increasing duration (6-72 h) of treatment with HS (200 micrograms/ml) led to a time-dependent decrease in GnRH-stimulated FSH release, achieving statistical significance by 12 h. Porcine ACTH had no influence on basal and GnRH-stimulated FSH secretion. CRF decreased GnRH-stimulated FSH secretion in a dose-dependent manner, and the inhibitory effect required preincubation (6-18 h) with CRF. HS inhibited the FSH secretory responses to phospholipase C, melittin, and 8-bromo-cAMP but did not affect the response to 1,2-dioctanoyl-sn-glycerol and ionophore A23187. These results indicate that both cortisol and CRF can act directly on pig pituitary to inhibit FSH responsiveness to GnRH.
 ...
PMID:Actions of corticotropin-releasing factor or cortisol on follicle-stimulating hormone secretion by isolated pig pituitary cells. 839 May 96

Biochemical properties of a termostable alkaline phosphatase obtained from the mycelium extract of A. caespitosus were described. The enzyme was purified 42-fold with 32% recovery by DEAE-cellulose and concanavalin A-Sepharose chromatography. The molar mass estimated by Sephacryl S-200 or by 7% SDS-PAGE was 138 kDa and 71 kDa, respectively, indicating a homodimer. Temperature and pH optima were 80 degrees C and pH 9.0. This enzyme was highly glycosylated (approximately 74% saccharide content). The activity was enhanced by Mg2+ (19-139%), NH4+ (64%), Na+ (51%) and Mn2+ (38%). 4-Nitrophenyl phosphate (4-NPP) was preferentially hydrolyzed, but glucose 1-phosphate (93%), UTP (67%) and O-phosphoamino acids also acted as substrates. V(lim) and K(m) were 3.78 nkat per mg protein and 270 micromol/L in the absence of Mg2+ and 7.35 nkat per mg protein and 410 micromol/L in the presence of Mg2+, using 4-NPP as substrate. The purified alkaline phosphatase removed the 5'-phosphate group of a linearized plasmid without showing DNAase activity, indicating its potential for recombinant DNA technology.
 ...
PMID:Purification and biochemical characterization of a mycelial alkaline phosphatase without DNAase activity produced by Aspergillus caespitosus. 1770 60