Corticotropin releasing factor stimulates adrenocorticotropin and β-endorphin release from AtT-20 mouse pituitary tumor cells

Hook, Vivian; Heisler, Seymour; Sabol, Steven L.; Axelrod, Julius

doi:10.1016/0006-291x(82)91264-5

Cited by 106 publications

(52 citation statements)

References 11 publications

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“…These doses can be estimated to have resulted in initial plasma levels of '400 pg/ml and 5 ng/ml, or -100 pM and 1 nM, respectively. The minimally effective dose of CRF in vitro had been found to be <10 pM in rat anterior pituitary cell cultures (5) and -2 nM in mouse AtT20/D16-16 anterior pituitary tumor cells (27 as contributing to the total IR-ACTH response after high doses of CRF. However; there was no apparent correlation between the magnitude of the IR-ACTH increment and subjective or objective manifestations of stress in individual subjects, no apparent difference in IR-ACTH increments after bolus injections vs. 30-s infusions of CRF, despite the fact that the latter produced less symptoms, and no increase in serum IR-GH, which is generally thought to be a sensitive index of stress, in any of the subjects receiving the highest two doses of CRF.…”

Section: Discussionmentioning

confidence: 99%

Effect of synthetic ovine corticotropin-releasing factor. Dose response of plasma adrenocorticotropin and cortisol.

Orth¹,

Jackson²,

DeCherney³

et al. 1983

J. Clin. Invest.

247

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A B S T R A C T Synthetic ovine corticotropin-releasing factor (CRF) was administered to normal male volunteer subjects as an intravenous bolus or 30-s infusion. Doses of CRF ranging from 0.001 to 30 sg/kg body wt were administered, and plasma immunoreactive (IR)-ACTH and IR-cortisol concentrations were measured. The threshold dose appeared to be 0.01-0.03 ag/kg, the half-maximal dose 0.3-1 sg/kg, and the maximally effective dose 3-10 ug/kg. Basal concentrations of IR-ACTH and IR-cortisol were 14±7.6 pg/ ml (mean±SD) and 5.6±2.2 gg/dl, respectively. IR-ACTH rose as early as 2 min after CRF injection, reached peak levels in 10-15 min, and declined slowly thereafter. IR-cortisol rose at 10 min or later and reached peak levels in 30-60 min. At a dose of 30 jig/ kg, neither IR-ACTH nor IR-cortisol fell from peak levels of 82±21 pg/ml (mean±SE) and 23±1.4 ,g/dl, respectively, during the 2-h course of the experiment, indicating that CRF has a sustained effect on ACTH release and/or a prolonged circulating plasma halflife. There was little or no increase in the levels of other anterior pituitary hormones. At doses of 1 gg/ Preliminary results of these studies were presented by Dr.

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Section: Discussionmentioning

confidence: 99%

Effect of synthetic ovine corticotropin-releasing factor. Dose response of plasma adrenocorticotropin and cortisol.

Orth¹,

Jackson²,

DeCherney³

et al. 1983

J. Clin. Invest.

247

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“…Microscopy-AtT-20 cells were cultured as previously described (19,20) on polylysine-coated glass chamber slides (Nalge Nunc International) and fixed with 4% paraformaldehyde in PBS for 10 min at room temperature. After permeabilization with Triton X-100 (0.1%), cells were incubated with PBS containing 3% BSA for 30 min at room temperature.…”

Section: Evaluation Of Cathepsin L Colocalization With Acth In Mouse mentioning

confidence: 99%

“…AtT-20 Cells-The mouse pituitary AtT-20 cell line produces ACTH and ␤-endorphin from POMC (19,20). The homogeneous nature of a clonal cell line allowed further assessment of the colocalization of cathepsin L with ACTH.…”

Section: Expression Of Cathepsin L Increases Acth and ␤-Endorphin Promentioning

confidence: 99%

Major Role of Cathepsin L for Producing the Peptide Hormones ACTH, β-Endorphin, and α-MSH, Illustrated by Protease Gene Knockout and Expression

Funkelstein

Toneff

Mosier

et al. 2008

Journal of Biological Chemistry

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The pituitary hormones adrenocorticotropic hormone (ACTH), ␤-endorphin, and ␣-melanocyte stimulating hormone (␣-MSH) are synthesized by proteolytic processing of their common proopiomelanocortin (POMC) precursor. Key findings from this study show that cathepsin L functions as a major proteolytic enzyme for the production of POMC-derived peptide hormones in secretory vesicles. Specifically, cathepsin L knockout mice showed major decreases in ACTH, ␤-endorphin, and ␣-MSH that were reduced to 23, 18, and 7% of wild-type controls (100%) in pituitary. These decreased peptide levels were accompanied by increased levels of POMC consistent with proteolysis of POMC by cathepsin L. The peptide hormones ACTH 2 , ␤-endorphin, and ␣-MSH are produced by proteolytic processing of their common proopiomelanocortin (POMC) prohormone precursor (1, 2). The mature peptide hormones are stored in pituitary secretory vesicles for regulated secretion and control of physiological functions in target organs. ACTH regulates the production of glucocorticoids in the adrenal cortex for control of metabolism (3, 4). ␣-MSH is implicated in the regulation of appetite and the production of melanin (5, 6). ␤-Endorphin is an endogenous opioid peptide involved in pain regulation (7,8). The proteolytic mechanisms that generate these functionally distinct peptide hormones from POMC are essential for these hormones to exert their biological functions.The role of cysteine protease activity for POMC processing has been implicated by several studies (9 -11), but the identity of the protease has not yet been achieved. In early studies of POMC processing activity in pituitary secretory vesicles, cysteine protease activity represented a significant portion of POMC cleaving activity, based on its inhibition by the thiol reagent p-chloromercuribenzoate (9). In anterior and intermediate pituitary cells in culture, treatment of cells with the cysteine protease inhibitor E64d reduced cell levels of POMC-derived ACTH, ␤-endorphin, and ␣-MSH (10, 11). Thus, it is likely that a cysteine protease participates in POMC processing. Participation of a cysteine protease in POMC processing would represent a new protease pathway, in addition to the subtilisinlike prohormone convertase enzymes (PC2 and PC1/3) that participate in processing POMC (12)(13)(14)(15). Therefore, the goal of this study was to identify the cysteine protease that produces ACTH, ␤-endorphin, and ␣-MSH peptide hormones derived from POMC.Herein we provide evidence indicating a key role for the cysteine protease cathepsin L in the biosynthesis of ACTH, ␤-endorphin, and ␣-MSH in secretory vesicles. Cathepsin L gene knock-out mice showed major reductions in pituitary tissue levels of ACTH, ␤-endorphin, and ␣-MSH. Furthermore, cathepsin L KO mouse pituitaries displayed accumulation of POMC, consistent with proteolysis of POMC by cathepsin L. In vivo cellular localization of cathepsin L in pituitary cells demonstrated a high degree of colocalization with ␤-endorphin, ␣-MSH, and ACTH in secretory vesicles. Ex...

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“…The ability of phorbol esters and diacylglycerol analogues to stimulate ACTH secretion from intact AtT-20 cells remaining attached to the culture dishes was measured as previously described (Hook et al, 1982). Drugs were added to the 1 ml of DMEM/BSA bathing the cells in the wells of the culture dishes.…”

Section: Measurement Of Stimulated a Cth Secretion From Intact Cellsmentioning

confidence: 99%

Effects of protein kinase C activators upon the late stages of the ACTH secretory pathway of AtT‐20 cells

McFerran

Guild

1994

British J Pharmacology

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1 The mouse AtT-20/D16-16 anterior pituitary tumour cell line was used as a model system for the study of phorbol 12-myristate 13-acetate (PMA)-mediated enhancement of calcium-evoked adrenocorticotrophin (ACTH) secretion. 2 PMA stimulated ACTH secretion from intact cells in a concentration-dependent manner. Other phorbol esters; phorbol 12,13-dibutyrate (PDBu) and phorbol 12,13-didecanoate (PDD) and diacylglycerol analogues; 1-oleoyl-2-acetyl-sn-glycerol (OAG) and 1,2-dioctanoyl-sn-glycerol (DOG) also stimulated ACTH release from intact AtT-20 cells. This would suggest that activation of protein kinase C (PKC) stimulates ACTH secretion from 3 Calcium stimulated ACTH secretion from electrically-permeabilized cells over the concentration- 6 GTP-y-S (108-1O'-M) stimulated ACTH secretion from permeabilized cells either in the presence or absence of ATP (5 mM) indicating that its effects on secretion are ATP-independent. 7 The results of the present study support the hypothesis that, in AtT-20 cells, PMA is acting at some site distal to calcium entry which modulates the ability of an increase in cytosolic calcium concentration to stimulate ACTH secretion. This site of action is either at the level of or at some stage distal to a GTP-binding protein which mediates the effects of calcium upon secretion. 8 PMA, unlike adenosine 3':5'-cyclic monophosphate (cyclic AMP) (Guild, 1991), can stimulate ACTH secretion from permeabilized cells in the absence of added calcium and guanine nucleotides which suggests that PMA and cyclic AMP are acting through distinct mechanisms at this post calcium site of action.

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Corticotropin releasing factor stimulates adrenocorticotropin and β-endorphin release from AtT-20 mouse pituitary tumor cells

Cited by 106 publications

References 11 publications

Effect of synthetic ovine corticotropin-releasing factor. Dose response of plasma adrenocorticotropin and cortisol.

Effect of synthetic ovine corticotropin-releasing factor. Dose response of plasma adrenocorticotropin and cortisol.

Major Role of Cathepsin L for Producing the Peptide Hormones ACTH, β-Endorphin, and α-MSH, Illustrated by Protease Gene Knockout and Expression

Effects of protein kinase C activators upon the late stages of the ACTH secretory pathway of AtT‐20 cells

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