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 mechanism of corticotropin stimulation of the synthesis of a specific rat adrenal cytosolic protein was investigated. This protein (protein E) has a mol.wt. of approx. 30000. It is detected by polyacrylamide-gel electrophoresis of cytosol prepared from adrenal slices from rats treated with corticotropin in vivo and control rats, the slices being incubated with [(3)H]- and [(14)C]-leucine respectively. In rats 1-15 days after hypophysectomy, corticotropin, like dibutyryl cyclic AMP, induces an increase in protein E similar to that induced in control rats, even though both compounds no longer stimulate total protein synthesis. Corticotropin stimulation of protein E synthesis is mediated by cyclic AMP but not by corticosterone, since aminoglutethimide, a steroidogenic inhibitor, does not affect corticotropin stimulation, and dexamethasone alone has no effect. Actinomycin D, when injected in vivo 1h before or after corticotropin injection, prevents the effect of corticotropin on protein E synthesis, which is interpreted as evidence that mRNA synthesis is necessary for the stimulation of protein E synthesis. When injected more than 2h after corticotropin, actinomycin D does not prevent corticotropin stimulation of protein E synthesis, but completely blocks corticotropin stimulation of total protein synthesis. This is interpreted as meaning that, after stimulation of mRNA coding for protein E, corticotropin has no effect on the synthesis of protein E. On the other hand, corticotropin stimulation of protein E synthesis persists after hypophysectomy even though it no longer stimulates total protein synthesis. These data suggest that the factor(s) involved in the synthesis of protein E are more stable than those involved in total protein synthesis.
 ...
PMID:Corticotropin regulation of the synthesis of a specific rat adrenal cytosolic protein. Effects of hypophysectomy and actinomycin D. 22 25

In the steroidogenic pathway of the adrenal cortex, 17 alpha-hydroxylase cytochrome P-450 (P-450(17 alpha)) is a major regulatory enzyme. Previous studies have shown that stimulation of 17 alpha-hydroxylase activity occurs upon treatment of bovine adrenocortical cells in culture with adrenocorticotropic hormone (ACTH), via cAMP, due to an increase in the enzyme concentration. Alterations in the levels of this enzyme result in pronounced changes in the pattern of steroids produced, with the potent glucocorticoid cortisol, as well as the sex steroids, being products of 17 alpha-hydroxylated steroid precursors. In the present study, the identification and sequencing of two cloned DNA molecules, pB17 alpha-1 and pcD17 alpha-2, which are complementary to mRNA sequences encoding bovine adrenal cortex P-450(17 alpha), are reported. Clone pcD17 alpha-2 contains an open reading frame coding for the complete amino acid sequence of P-450(17 alpha) which consists of 509 amino acids and has a molecular weight of 57,251. By comparison to other forms of cytochrome P-450, we conclude that P-450(17 alpha) is a member of a previously unidentified family within the P-450 multigene superfamily. Single bovine and human mRNA species of approximately equal to 1850 bases in length hybridize to these clones. Regulation of the concentration of this RNA has been studied using bovine adrenocortical cells in culture. Treatment with ACTH or dibutyryl cAMP causes an increase in the content of P-450(17 alpha) RNA in as little as 2 h, and its concentration increases greater than 20-fold by 8 h. In contrast, other steroidogenic enzymes that have been studied respond more slowly to ACTH. Actinomycin D and cycloheximide block induction of P-450(17 alpha) RNA, indicating that regulation of 17 alpha-hydroxylase activity is controlled at the level of transcription and requires ongoing protein synthesis.
 ...
PMID:Bovine adrenocortical cytochrome P-450(17 alpha). Regulation of gene expression by ACTH and elucidation of primary sequence. 300 17

Circulating human gamma-melanotropin precursor (76 amino acids) [N-POC(1-76) enhances the corticosterone and aldosterone response to corticotropin by isolated perfused rat adrenal cells [Al-Dujaili, Hope, Estivariz, Lowry & Edwards (1981) Nature (London) 291, 156-159]. Actinomycin D (4 x 10(-6) mol/litre) did not significantly affect corticotropin-induced corticosterone or aldosterone outputs, but completely inhibited the potentiating action of gamma-melanotropin precursor on rat adrenal cells. This suggests that the precursor enhances corticotropin-induced steroidogenesis via an increase in available mRNA produced from DNA transcription.
 ...
PMID:Human gamma-melanotropin precursor potentiates corticotropin-induced adrenal steroidogenesis by stimulating mRNA synthesis. 628 16

Previous reports have demonstrated that corticotropin-releasing hormone (CRH) treatment of primary cultures of mouse Leydig cells and MA-10 mouse Leydig tumor cells results in a dose-dependent stimulation of steroidogenesis, probably by acting through the cAMP/protein kinase A second messenger pathway. Based on this observation, the mechanism of CRH-stimulated steroidogenesis is now further investigated and compared to trophic hormone stimulation. Both cell types were treated with human chorionic gonadotropin (hCG) or CRH in the absence and presence of the following agents: the translation inhibitor cycloheximide, the transcription inhibitor actinomycin D, the protonophore carbonyl cyanide m-chlorophenylhydrozone (mCCCP), which disrupts the mitochondrial electrochemical gradient or the phorbol ester, phorbol-12-myristate 13-acetate (PMA), a stimulator of protein kinase C. Cortico-releasing hormone-stimulated steroidogenesis was completely blocked by cycloheximide in both cell types, indicating that CRH-stimulated steroidogenesis in mouse Leydig cells requires ongoing protein synthesis. Actinomycin D had profound inhibitory effects on CRH-stimulated steroidogenesis in MA-10 cells, and this inhibition was greater than that seen in mouse primary Leydig cells. mCCCP severely inhibited CRH-stimulated steroid production in both cell types, indicating that an electrochemical gradient across the inner mitochondrial membrane is required for CRH-stimulated steroidogenesis. In addition, PMA inhibited hCG- and CRH-stimulated steroidogenesis in MA-10 cells and CRH-stimulated steroidogenesis in primary Leydig cells, suggesting that activation of the protein kinase C pathway can influence protein kinase A stimulated steroidogenesis. Results of these studies suggest that the mouse Leydig cell steroidogenic response to CRH shares many similarities to that of the LH response.
 ...
PMID:The cellular mechanisms of corticotropin-releasing hormone (CRH)-stimulated steroidogenesis in mouse Leydig cells are similar to those for LH. 934 51

Heme oxygenase (HO) catalyzes the first and rate-controlling step of heme catabolism into biliverdin, iron and carbon monoxide. Three isoforms of HO have been identified so far: the inducible HO-1 and the constitutive HO-2 and HO-3. Both HO-1 and HO-2 were expressed in zona fasciculata (ZF) adrenal cells and in a mouse adrenocortical cell line (Y1). HO-1 but not HO-2 expression was upregulated by adrenocorticotropic hormone (ACTH) and accumulation of HO-1 protein correlated with an increase in HO activity in Y1 cells. ACTH induced HO-1 expression in a time- and dose-dependent manner with a maximum after 5 h of treatment and a threshold concentration of 0.1 mIU/ml. Actinomycin D and cycloheximide completely blocked the effect of ACTH on HO-1 mRNA expression whereas mRNA stability was not affected by ACTH. Permeable analogs of cAMP mimicked the effect of ACTH on HO-1 expression and ACTH induction was prevented by the protein kinase A (PKA) inhibitor H89. Steroid production was significantly increased when both HO-1 and HO-2 activities were inhibited by Sn-protoporphyrin IX (SnPPIX). The lipid peroxidation and increase in carbonyl content triggered by hydrogen peroxide was prevented by treatment of Y1 cells with bilirubin and ACTH.
 ...
PMID:Adrenocorticotropin induces heme oxygenase-1 expression in adrenal cells. 1470 50