Evidence that long-term administration of a methionine-enkephalin analogue stimulates the growth and steroidogenic capacity of rat inner adrenocortical cells

Andreis, P. G.; Belloni, A. S.; Cavallini, L; Mazzocchi, Giuseppina; Nussdorfer, Gastone G.

doi:10.1016/0143-4179(88)90049-2

Cited by 11 publications

(2 citation statements)

References 25 publications

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“…Studies of the effects of enkephalins on adrenal steroidogenesis have mostly used an analogue of met-enkephalin, D-ala2-met-enkephalinamide (DALA). Long-term administration of this peptide has been shown to stimulate the growth and steroidogenic capacity of both zona glomerulosa and zonae fasciculata/reticularis of intact rats treated with dexamethasone and captopril, to inhibit both the secretion of ACTH and the renin-angiotensin system (99)(100)(101). Short term administration of DALA to these dexamethasone treated animals had no effect on corticosterone secretion (99), and this is in agreement with an earlier study ( 102).…”

Section: Evidence For Neural Regulation Of Adrenocortical Functionsupporting

confidence: 88%

The Neuroendocrinology of the Adrenal Cortex

Vinson

Hinson

Tóth

1994

J Neuroendocrinology

108

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Although until relatively recently assumed to be devoid of innervation, there is now ample proof that the adrenal cortex receives specific neurones of several types. A general interpretation of their roles in the regulation of adrenocortical function has not been forthcoming, probably because of the variety of the different experimental approaches which have been used, and the heterogeneous observations which have been made. We here summarize the evidence which is available, and offer the view that neural inputs may provide fine tuning of the responses to systemic factors such as ACTH, through direct actions on specific adrenocortical cells. However, neural regulation also provides an integrative function, through actions on the flow of blood through the gland, which itself exerts a powerful influence on adrenocortical function.

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Section: Evidence For Neural Regulation Of Adrenocortical Functionsupporting

confidence: 88%

The Neuroendocrinology of the Adrenal Cortex

Vinson

Hinson

Tóth

1994

J Neuroendocrinology

108

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“…There are several alternative hypotheses to explain such a discrep ancy: (i) strain-dependent changes in adrenal responsive ness to circulating ACTH [37] or in corticosterone metab olism: (ii) the existence of ACTH-independent mecha nisms involved in the control of adrenocortical secretion [56.57], Among the latter one could consider: (a) splanch nic innervation of the adrenal, which enhances blood flow to the adrenal cortex and the sensitivity to ACTH [58,59] and involves local release of CRF and other neuropep tides [60,61]; (b) the role of several peptides, including those derived from pro-opiomelanocortin, which are re leased into the blood during stress and are able to increase the adrenocortical response to circulating ACTH [62][63][64], Focusing on LEW rats, the results suggest that the blunted B response to chronic IMO observed in LEW rats is not apparently caused by a defect in basal serum ACTH or in basal PVN CRF biosynthesis. Although it has been shown that the hyporesponsiveness of LEW rats to acute stress is secondary to a defect in hypothalamic CRF bio synthesis and secretion [43,65], it should be taken into account that: (i) the effects of chronic stress on basal CRF mRNA are not comparable to those induced by acute stress; (ii) changes in mRNA cannot be assumed to be always a reflection of peptide activity/secretion since posttranscriptional mechanisms and particularly peptide release might be differentially affected; (iii) in vitro basal hypothalamic arginine vasopressin release is higher in LEW than in FIS rats and this might, at least partially, compensate for the insufficient CRF secretion [66].…”

Section: Discussionmentioning

confidence: 99%

Hypothalamic-Pituitary-Adrenal Response to Chronic Stress in Five Inbred Rat Strains: Differential Responses Are Mainly Located at the Adrenocortical Level

Gómez

Lahmame

Kloet³

et al. 1996

Neuroendocrinology

248

137

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The effects of chronic stress on the hypothalamic-pituitary-adrenocortical (HPA) axis were studied in five inbred rat strains, i.e. Brown Norway (BN), Fischer (FIS), Lewis (LEW), Spontaneously Hypertensive (SHR) and Wistar Kyoto (WKY). Previously, these rat strains had been shown to display clear behavioral differences in the forced swimming test that presumably measures depression-like behavior, BN and WKY being more passive than the other strains. Here we test the hypothesis that the differences in behavioral immobility might be associated with an abnormal HPA response to chronic immobilization (IMO) stress. In stress-naive rats under basal conditions (morning) there were no differences among strains in adrenal weight, serum adrenocorticotropin hormone (ACTH) and corticosterone (B) levels, corticotropin-releasing factor (CRF) mRNA in the hypothalamic paraventricular nucleus (PVN) and hippocampal glucocorticoid and mineralocorticoid receptor (GR and MR) mRNA. After chronic IMO, basal serum ACTH levels were increased in LEW, SHR and WKY, but not in BN or FIS rats, whereas basal B levels were increased in BN, FIS, SHR and WKY rats, but not in LEW. The increase in adrenal weight was also strain dependent and correlated negatively with chronic IMO-induced hypercorticosteronemia. These peripheral differences among strains were not observed at central levels. Thus, chronic IMO increased the CRF mRNA content in the PVN, analyzed by in situ hybridization, similarly in all strains. In addition, after chronic IMO no differences were found among strains in hippocampal GR mRNA and RM mRNA contents. Considering data from all strains together, chronic IMO reduced the GR mRNA (50-60%) content in the hippocampal CA1, CA3 and DG areas, and slightly diminished (11–13%) MR mRNA levels in CA1 and CA3 areas. The present results indicate that: (i) chronic IMO down-regulates GR mRNA in the hippocampus and slightly up-regulates CRF mRNA in the hypothalamic PVN similarly in all strains; (ii) after chronic IMO interstrain differences were observed in serum ACTH and B levels as well as adrenal hypertrophy; (iii) some changes are probably located at the adrenal level since changes in serum B level and adrenal weight were not related to changes in ACTH; (iv) in LEW and WKY rats, B hyporesponsiveness to chronic IMO might be linked to low adrenal sensitivity to ACTH, and (v) HPA axis changes induced by the chronic IMO procedure are not related to previously reported data on depressive-like behavior of BN and WKY in the forced swimming test.

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Peptide and Protein Hormones

König

2000

Ullmann's Encyclopedia of Industrial Chemistry

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Evidence that long-term administration of a methionine-enkephalin analogue stimulates the growth and steroidogenic capacity of rat inner adrenocortical cells

Cited by 11 publications

References 25 publications

The Neuroendocrinology of the Adrenal Cortex

The Neuroendocrinology of the Adrenal Cortex

Hypothalamic-Pituitary-Adrenal Response to Chronic Stress in Five Inbred Rat Strains: Differential Responses Are Mainly Located at the Adrenocortical Level

Peptide and Protein Hormones

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