Gamma-endorphin-like peptides in pituitary tissue: Evidence for their existence in vivo

Dorsa, Daniel M.; Chapman, Margaret B.; Baskin, Denis G.

doi:10.1016/0196-9781(82)90107-3

Cited by 18 publications

(9 citation statements)

References 15 publications

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“…In the anterior lobe most of the y-endorphin IR is present in a lipotropin variant of y-endorphin [5]. Secondly, y-endorphin is re leased in vitro from the intermediate pituitary after adren ergic and noradrenergic stimulation [10,II,32], Thirdly, it has been demonstrated recently, using the protein A-immunogold method at the electron microscopic level, that P-endorphin and y-endorphin are co-localized in pituitary secretory granules [35]. Therefore, secretory granules are a putative site of y-endorphin formation which so far has not been investigated biochemically.…”

Section: Discussionmentioning

confidence: 99%

“…nular localization has been demonstrated in the intermed iate pituitary gland [10,35], and y-endorphin can be released from the pituitary gland in vitro [II,32], These data point to the existence of an intracellular endopepti dase cleaving the Leur -Phe18 bond in (l-endorphin. The enzyme activity responsible for the cleavage has been term ed tentatively 'y-endorphin-generating endopeptidase' (yEGE) [2,21].…”

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confidence: 97%

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Leu-Phe Cleaving Endopeptidase Activity, γ-Endorphin, and β-Endorphin in the Rat Pituitary Gland and Brain

Lebouille¹,

Burbach²,

Kloet³

et al. 1988

Neuroendocrinology

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The influence of adrenalectomy and corticosterone substitution was investigated on Leu-Phe cleaving endopeptidase activity and on the levels of γ-endorphin and β-endorphin in the pituitary gland and the brain. The enzyme activity was quantitated by a specific radiometric assay based on the cleavage of the Leu¹⁷-Phe¹⁸ bond in a NH₂ and COOH-terminally protected synthetic substrate wich was analogous to β-endorphin-(15–19). This activity may mimick the formation of γ-endorphin. β-Endorphin and γ-endorphin were measured by specific radioimmunoassays. After 14 days of adrenalectomy enzyme activity had increased in anterior (15%) and neurointermediate lobes of the pituitary gland (30%), hypothalamus (25%), and liver (15%). This increase was prevented when the adrenalectomized animals were subjected to chronic corticosterone substitution by subcutaneous implantation of a pellet of 100 mg. Extirpation of only the adrenal medulla did not affect the Leu-Phe cleaving activity. Enzyme activity in the septum, hippocampus, and cerebellum had not changed after adrenalectomy. Determination of immunoreactive levels of γ- and β-endorphins showed that in the anterior pituitary gland γ- and β-endorphins had increased by 275 and 300%, respectively, 14 days after adrenalectomy. No significant changes were observed in endorphin levels of the intermediate lobe of the pituitary gland, hypothalamus, hippocampus, and septum. The results indicate that Leu-Phe cleaving endopeptidase activity is sensitive to glucocorticoids in tissues containing proopiomelanocortin-producing cells, i.e., anterior and neurointermediate pituitary gland and the hypothalamus. In the anterior pituitary gland it is correlated with the levels of γ- and β-endorphins.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 97%

Leu-Phe Cleaving Endopeptidase Activity, γ-Endorphin, and β-Endorphin in the Rat Pituitary Gland and Brain

Lebouille¹,

Burbach²,

Kloet³

et al. 1988

Neuroendocrinology

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“…Dorsa et al (1982) detected in rat pituitary a large peptide cross-reacting with an antiserum for the COOH-terminus of 7-endorphin (fl-endorphin-(1-17)) and suggested that it was related to this fl-lipotropin-(1-77) (rat fl-lipotropin-(1-56)). Recently, Burbach and Wiegant (1984) detected in human pituitaries a similar peptide in considerable amounts cross-reacting with a COOH-terminal 7-endorphin antiserum (Loeber et al, 1979;Loeber and Verhoef, 1981).…”

Section: T~-lipotropin-(1-77)/-(l-75)mentioning

confidence: 99%

“…Subsequently, several reports have indicated indirectly the presence of ~t-and 7-endorphins in pituitary tissue by detecting peptides with opiate-like properties of the size of these/~-endorphin fragments (Giagnoni et al, 1977;Sabol, 1978;Lissitsky et al, 1978). Peptides related to ct-and 7-endorphin have been immunologically and/or chromatographically characterized in extracts of rat anterior and intermediate pituitary (Jegou et al, 1978(Jegou et al, , 1979Fukata et al, 1979;Verhoef et al, 1980aVerhoef et al, ,b, 1982Dorsa et al, 1982;Wiegant et al, 1983a,b), in rat brain (Verhoef et al, 1980(Verhoef et al, , 1982aDorsa et al, 1981;Wiegant et al, 1983a,b), in human pituitary and brain (Burbach and Wiegant, 1983; unpublished observations), in guinea pig myenteric plexus (Opmeer et al, 1980), and in rat testicular tissue (Tsong et al, 1982;Shu-Dong et al, 1982;Margioris et al, 1983). Immunohistochemical localization studies have shown the storage of ct-endorphin and 7-endorphins in pituitary and rat brain (B6geot et al, 1978;Vaudry et al, 1980).…”

Section: Fl-endorphin Fragments: ~-And 7-endorphinsmentioning

confidence: 99%

Action of proteolytic enzymes on lipotropins and endorphins: Biosynthesis, biotransformation and fate

Burbach¹

1984

Pharmacology & Therapeutics

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“…In testis, POMC messenger RNA and /3-endorphin have specifically been demonstrated in the Leydig cells (16)(17)(18), and a-endorphin and 7-endorphin in germinal cells (spermatogonia and spermatocytes) (19). The ratio of 7-endorphin to /S-endorphin is much higher in testis than in brain or pituitary (12,(14)(15)(16)(17)20). It is unknown whether the conversion of /?-endorphin into «-and 7-endorphin takes place in the Leydig or germinal cells.…”

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confidence: 96%

γ-Endorphin-Generating Endopeptidase: Distribution in Body Tissues and Cellular Localization in Rat Testis*

et al. 1986

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The Leu17-Phe18 bond of beta-endorphin is cleaved by a specific endopeptidase that generates the biologically active peptide gamma-endorphin. gamma-Endorphin-generating endopeptidase (gamma EGE) activity was determined by a radiometric assay, using as substrate a radioactively labeled, N- and C-terminally protected pentapeptide: Ac-Val-Thr-Leu-Lys( [14C]CH3)2-NHCH3, a derivative of beta-endorphin-(15-19). Here we report the tissue distribution of gamma EGE activity and its cellular localization in the testis. gamma EGE activity was present in the cytosolic fraction of most tissues. Highest specific activity occurred in the testis, ovary, and the uterus (10-16 nmol X mg protein-1 X h-1). In testis highest specific gamma EGE activity was found in the tubules (42 nmol X mg protein-1 X h-1) and lowest in Leydig cells (8 nmol X mg protein-1 X h-1). Further fractionation of the tubules showed that the germinal cell fraction had a higher specific activity (24 nmol X mg protein-1 X h-1) than the Sertoli cell fraction (8 nmol X mg protein-1 X h-1). In testis depleted of the germinal cells by prenatal irradiation of the rat or hypophysectomy, specific activity of gamma EGE activity decreased 50-fold and 4-fold, respectively. In testis depleted of Leydig cells by treatment of rats with ethane dimethyl sulfonate, specific gamma EGE activity did not decrease. Adrenalectomy had no effect on the enzyme activity. The results suggest that the germinal cells are sites of processing of beta-endorphin into alpha- and gamma-endorphins. It is concluded that 1) gamma EGE activity is widely distributed in tissues; 2) highest gamma EGE activity is located in reproductive tissues; and 3) in the testis gamma EGE activity is mainly associated in the germinal cells.

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Gamma-endorphin-like peptides in pituitary tissue: Evidence for their existence in vivo

Cited by 18 publications

References 15 publications

Leu-Phe Cleaving Endopeptidase Activity, γ-Endorphin, and β-Endorphin in the Rat Pituitary Gland and Brain

Leu-Phe Cleaving Endopeptidase Activity, γ-Endorphin, and β-Endorphin in the Rat Pituitary Gland and Brain

Action of proteolytic enzymes on lipotropins and endorphins: Biosynthesis, biotransformation and fate

γ-Endorphin-Generating Endopeptidase: Distribution in Body Tissues and Cellular Localization in Rat Testis*

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