Occurrence of two different endorphins in the salmon pituitary

Kawauchi, Hiroshi; Tsubokawa, Makoto; Kanezawa, Atsushi; Kitagawa, Hiroaki

doi:10.1016/0006-291x(80)90425-8

Cited by 79 publications

(13 citation statements)

References 18 publications

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“…The data for the first time implicate a NIL N-terminally acetylated /3-endor- supported by recent work demonstrating specific effects of Nacetylated /3-END on prolactin cell recruitment in rats (12). The data on endorphin-like material in tilapia pituitary homogenates and NIL superfusate comply with results published previously on endorphin synthesis and processing in fish (11,15). We used a heterologous RIA, but conclude that the assay detected tilapia N-acetylated endorphins on the basis of the paralellism between the displacement curves obtained with the RIA standard, he tilapia pituitary homogenate, and the tilapia and trout plasma pools.…”

Section: Discussionsupporting

confidence: 89%

Endorphin and MSH in concert form the corticotropic principle released by tilapia (Oreochromis mossambicus; Teleostei) melanotropes

1995

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diacetyl-tt-MSH. Evidence is presented that the noteworthy corticotropic potency of this HPLC fraction, previously attributed to diacetyl-tt-MSH, results from END and MSH acting in a coordinated fashion. Confinement stress had no effect on plasma N-ac-/?-END immunoreactivity, but led to a decrease in plasma or-MSH levels. Therefore, it seems unlikely that the corticotropic action of the peptides regulates the elevation of cortisol production that takes place during confinement, but it may play a role during other forms of stress that are known to activate the melanotropes.

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Section: Discussionsupporting

confidence: 89%

Endorphin and MSH in concert form the corticotropic principle released by tilapia (Oreochromis mossambicus; Teleostei) melanotropes

1995

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“…Several forms of endogenous opioid peptides (Follenius and Dubois, 1979;Kawauchi et al, 1980;Salbert et al, 1992) as well as the specific opioid receptors (Bird et al, 1988;Rosenblum and Callard, 1988) were found in the fish brain and in the pituitary gland. By in vivo and in vitro investigations on goldfish and common carp (Rosenblum and Peter, 1989;Cheng, 1996;Sokolowska-Mikolajczyk et al, 2002a,b;Socha et al, 2003;Sokołowska-Mikołajczyk et al, 2005) ABSTRACT: Dispersed cells from sexually immature carp (footlings) pituitaries were exposed to estradiol (E 2 ) or testosterone (T) (both at 3 × 10 -8 M) in the presence of opioid receptor antagonist naltrexone (10 -8 or 10 -6 M) and/or agonist -morphine (10 -8 or 10 -6 M).…”

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confidence: 99%

Steroid effects on the in vitro LH secretion from pituitary cells of sexually immature carp (Cyprinus carpio L.) under the influence of naltrexone and morphine

Sokolowska-Mikolajczyk¹,

Socha²,

Epler³

2010

CZECH J ANIM SCI

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Dispersed cells from sexually immature carp (footlings) pituitaries were exposed to estradiol (E2) or testosterone (T) (both at 3 × 10–8 M) in the presence of opioid receptor antagonist naltrexone (10–8 or 10–6 M) and/or agonist – morphine (10–8 or 10–6 M). Naltrexone alone at 10–6 M increased the LH level as compared with the control. Morphine (10–8 or 10–6 M), T and E2 had no influence on LH levels. The combination of T with naltrexone (10–8 M) stimulated LH release if compared with the control or with T alone. Morphine (both concentrations) with T caused significantly higher LH secretion than the control medium and T alone. Estradiol with naltrexone (10–8 and 10–6 M) had no influence on LH concentration. In media with E2 and morphine (10–8 M) LH levels were higher than in the control and estradiol alone. The results show that in common carp sex steroids affect the response of pituitary cells to opioid agonist or antagonist giving an evidence on the role of steroids in LH release mediated by the opioid system.

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“…Evidence already has been provided for two distinct proopiomelanocortin-related precursors in the pituitary of fish and amphibians (31,32 [Met]enkephalinArg6-Gly7-Leu8 was detected, significant octapeptide immunoreactivity (>10 pmol/g) was present in higher molecular weight peptide(s) (Mr 2,000-3,000). Thus, avian proenkephalin is also closely related to the mammalian precursor.…”

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confidence: 99%

Evidence for a proenkephalin-like precursor in amphibian brain.

Kilpatrick¹,

Howells²,

Lahm³

et al. 1983

Proc. Natl. Acad. Sci. U.S.A.

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The mammalian proenkephalin-derived peptides [Leu]enkephalin, [Metlenkephalin, and [Met]enkephalin-Arg6-Phe7 were identified in acid extracts of the brain of Bufo marinus by using reversed-phase HPLC and specific radioimmunoassays.[Met]Enkephalin was the predominant opioid peptide present (270 pmol/g). In contrast, the octapeptide [Met]enkephalin-Arg6-Gly7-Leu8, which is also derived from mammalian proenkephalin, was not detected. The ratio of free [Met]enkephalin to [Met]enkephalin-Arg6-Phe7 was found to be 3.5 to 1, which is similar to that observed in mammalian proenkephalin-containing tissues. Together these data (i) indicate that amphibian brain contains a proenkephalin related to the mammalian precursor and (ii) establish the existence of enkephalins and proenkephalin-derived enkephalincontaining peptides in a submammalian species.It is now well established that the opioid pentapeptides [Met]-enkephalin and [Leu]enkephalin are generated from a common precursor molecule, proenkephalin (1, 2). Evidence for this biosynthetic pathway has been found in all mammalian species examined (3-6). There also have been numerous reports of enkephalin-like substances in lower vertebrate and invertebrate tissues (7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20). Although it has been assumed that these materials represent enkephalins, such studies were based mainly on immunohistochemistry or radioligand displacement assays performed on crude tissue extracts. In no case has there been a critical biochemical characterization of nonmammalian enkephalin-like material. To our knowledge, the presence of free enkephalins and the proenkephalin biosynthetic pathway in submammalian species has yet to be established.We have been examining the distribution of enkephalins and proenkephalin-derived peptides in several submammalian species by gel filtration and high-performance liquid chromatography. Here RESULTS AND DISCUSSION Sephadex G-75 chromatography of toad brain acid extracts revealed the presence of significant amounts of enkephalin immunoreactivity (Fig. 1). After digestion with trypsin and carboxypeptidase B, enkephalin activities appeared in both the low and high molecular weight regions.[Met]Enkephalin-immunoreactive peptides were clearly predominant. The enkephalin-containing peptides present in the Sephadex G-75 salt volume fractions were resolved by using reversed-phase HPLC on a C18 column. Several enkephalin-immunoreactive peptides were detected (Fig. 2). By far the most abundant peptide was eluted in the position of free [Met]enkephalin. Immunoreactive peaks corresponding to free [Leu]enkephalin and [Met]-enkephalinArg6-Phe7 were observed also. In mammals, the latter peptide is derived from the processing of proenkephalin (1-6, 27). All three enkephalin immunoreactive peaks also exhibited opiate receptor binding activities proportional to their immunoreactivities (Table 1). Interestingly, the octapeptide [Met]enkephalin-Arg6-Gly7-Leu8, which also is produced through the processing of mammalian proenkephal...

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Occurrence of two different endorphins in the salmon pituitary

Cited by 79 publications

References 18 publications

Endorphin and MSH in concert form the corticotropic principle released by tilapia (Oreochromis mossambicus; Teleostei) melanotropes

Endorphin and MSH in concert form the corticotropic principle released by tilapia (Oreochromis mossambicus; Teleostei) melanotropes

Steroid effects on the in vitro LH secretion from pituitary cells of sexually immature carp (Cyprinus carpio L.) under the influence of naltrexone and morphine

Evidence for a proenkephalin-like precursor in amphibian brain.

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