Paracrine control of adrenocortical function: a new role for the medulla?

Hinson, J. P.

doi:10.1677/joe.0.1240007

Cited by 123 publications

(44 citation statements)

References 25 publications

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“…This suggests either that adrenal cells from Taconic rats are more sensitive to ACTH in vivo than in vitro or that other factors are present in the circulation of Taconic rats that augment the steroidogenic response to ACTH. Although we have yet to test either possibility, several factors may augment adrenal sensitivity to ACTH in vivo, such as other pituitary and adrenomedullary peptides [13, 14], cortical vasodilation [15], and higher ratios of bioactive/inactive forms of circulating ACTH [8]. …”

Section: Discussionmentioning

confidence: 99%

Differential Sensitivity to ACTH, but Not Stress, in Two Sources of Outbred Sprague-Dawley Rats

Matthys¹,

Castello²,

Zilz³

et al. 1998

Neuroendocrinology

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Adrenocorticotropic hormone (ACTH) is the major regulator of adrenocortical steroidogenesis in mammals. By comparing the sensitivity to ACTH of isolated adrenocortical cells from two sources of the same strain (Sprague-Dawley, SD) of outbred rats, we have identified a source of rat with low sensitivity to ACTH in vitro. Cells isolated from Holtzman SD rats had a high sensitivity to ACTH (minimal effective concentration 50 pg/ml), whereas Taconic SD rats had a low sensitivity (minimal effective concentration 250 pg/ml; maximal steroidogenesis <50% of Holtzman cells). The responsiveness to analogues of cyclic adenosine monophosphate and cholesterol was also significantly lower in Taconic SD rats. Taconic adrenals were smaller, had significantly more mitochondria per cell, but approximately 20% less total lipid droplet volume per cell. There was no difference in latency to ACTH in vitro; however, steroidogenesis plateaued in Taconic cells after 25 min, while Holtzman cells secreted corticosterone almost linearly for at least 120 min. By contrast, the cyclic adenosine monophosphate secretion increased at the same rate for at least 120 min in cells from both sources. There were no differences between cells from the two sources in immunoreactive steroidogenic enzyme content. In vivo, the magnitude of the ACTH and corticosterone responses to two types of stress were similar in both sources. The thymus glands of Holtzman rats were significantly larger than those of Taconic rats. It is concluded that: (1) reduced sensitivity to ACTH in vitro in Taconic SD rats results from differences in the later stages of the steroidogenic pathway; (2) factors in addition to ACTH are required for maximal steroidogenesis in Taconic SD rats; (3) a comparison of the steroidogenic pathways in adrenal cells from these two sources of outbred rats should be useful in further delineating the relative importance of putative intracellular signalling mechanisms involved in initiation and maintenance of steroidogenesis, and (4) these data suggest that different sources of the same strain of rats sufficiently diverge over time to become separate strains (‘substrains’). Overreliance on a single source of laboratory rodent may obscure natural variability in endocrine responses to stress and provide a misleading indication of homogeneity of responses.

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Section: Discussionmentioning

confidence: 99%

Differential Sensitivity to ACTH, but Not Stress, in Two Sources of Outbred Sprague-Dawley Rats

Matthys¹,

Castello²,

Zilz³

et al. 1998

Neuroendocrinology

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“…It has been pointed out that in mammals, norepinephrin is converted to epinephrin efficiently in the united adrenal (Hinson, 1990).…”

Section: Physiological Demands For Ca Homeostasismentioning

confidence: 99%

Hormonal Control of Ca Homeostasis in Lower Vertebrates: Considering the Evolution

Sasayama

1999

Zoological Science

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“…It has been suggested that adrenomedullin is produced in the adrenal medulla and may be transported through the gland to act on the zona glomerulosa (Mazzocchi et al 1996b). Although it is clear that certain neuropeptides may be transported in nerve fibres from the adrenal medulla to the cortex (Hinson 1990), there is no evidence to date that adrenomedullin is found in the nerves supplying the adrenal gland.…”

Section: Introductionmentioning

confidence: 99%

Local production and action of adrenomedullin in the rat adrenal zona glomerulosa

Kapas¹,

Martı́nez²,

Cuttitta³

et al. 1998

Journal of Endocrinology

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This study was designed to investigate the synthesis and action of adrenomedullin in the rat adrenal gland. The results obtained from in situ hybridization and immunocytochemical studies suggest that adrenomedullin is synthesized not only in the medulla, but also within the zona glomerulosa of the rat adrenal cortex. Findings from in situ hybridization and binding studies also suggested that specific adrenomedullin receptors are expressed in the zona glomerulosa, and that low levels are present in the inner zones of the cortex. The K d of the zona glomerulosa adrenomedullin receptor (5·5 nmol/l) suggests that it may respond to locally produced adrenomedullin rather than circulating concentrations of the peptide, which are in a lower range. It was found that adrenomedullin acted on zona glomerulosa cells in vitro to stimulate aldosterone release and cAMP formation, but in this tissue did not stimulate inositol phosphate turnover. The effect of adrenomedullin on aldosterone secretion was significantly attenuated by a protein kinase A inhibitor, suggesting that cAMP mediates the effects of adrenomedullin on aldosterone secretion. Adrenomedullin did not significantly affect the response of zona glomerulosa cells to stimulation by either ACTH or angiotensin II. Adrenomedullin did not affect the release of catecholamines, either adrenaline or noradrenaline, by intact adrenal capsular tissue. These data suggest that both adrenomedullin and its specific receptor are expressed in the rat adrenal zona glomerulosa, leading to the hypothesis that adrenomedullin may have an autocrine/paracrine role in the regulation of the rat adrenal zona glomerulosa.

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Paracrine control of adrenocortical function: a new role for the medulla?

Cited by 123 publications

References 25 publications

Differential Sensitivity to ACTH, but Not Stress, in Two Sources of Outbred Sprague-Dawley Rats

Differential Sensitivity to ACTH, but Not Stress, in Two Sources of Outbred Sprague-Dawley Rats

Hormonal Control of Ca Homeostasis in Lower Vertebrates: Considering the Evolution

Local production and action of adrenomedullin in the rat adrenal zona glomerulosa

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