Heterogeneity of adrenocorticotrophin in the pituitary gland and plasma during the perinatal period

Dupouy, Jean‐Paul; Chatelain, A.

doi:10.1051/rnd:19850710

Cited by 4 publications

(3 citation statements)

References 50 publications

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“…In fact, there was a spontaneous in crease in corticosterone secretion both in the fetuses on day 19 of gestation and in the newborns [reviewed in ref. 21,22] which do not block concomitant testosterone surges under resting conditions. However, on day 19 of gestation, a substantial dif ference in control groups is noted for plasma testosterone con centrations; the levels were significantly lower in fetuses from solvent-injected mothers ( fig.…”

Section: Discussionmentioning

confidence: 99%

Reduction in Testicular Function in Rats

Ml²,

Df³

et al. 1990

Neuroendocrinology

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Chronic administration of dexamethasone in drinking water to maternal rats from days 15 to 21 of gestation (1) reduced plasma testosterone concentrations in male fetuses between days 19 and 21 but not earlier on day 18 and abolished the prenatal peak of plasma testosterone which normally occurs on day 19 of gestation, and (2) suppressed the postnatal surge of plasma testosterone in male newborns 1.5 and 2 h after delivery at term by cesarean section. The administration of dexamethasone to male fetuses at birth induced 1 h later a slight but not significant increase in hypothalamic gonadotropin-releasing hormone (GnRH) and pituitary luteinizing hormone (LH) contents, reduced drastically plasma LH levels and completely prevented the postnatal surge of plasma testosterone which occurred normally in littermate controls. A rise in pituitary LH content, and a sharp reduction in plasma LH and testosterone concentrations were noted in 19-day-old male fetuses whose mothers were acutely treated with dexamethasone on day 18 of gestation. Similar evolutions for LH were observed in littermate females. These results suggest that the inhibitory effects of exogenous glucocorticoids on testosterone secretion could be mediated in both fetuses and newborns at least partially through suppression of the hypothalamic and pituitary secretion of GnRH and LH, respectively, and provide insight how stress or hormone imbalance may affect the development of this neuroendocrine system.

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Section: Discussionmentioning

confidence: 99%

Reduction in Testicular Function in Rats

Ml²,

Df³

et al. 1990

Neuroendocrinology

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“…Immunological studies indicate that the relative proportions of the different molecular forms of ACTH in both the pituitary gland and plasma of rat foetuses change dramatically during gestation (Châtelain & Cheong 1985;Châtelain & Dupouy 1985) although their biological activity during foetal development is unknown. The aim of the present study was to compare in vitro the corticosteroidogenic effect of the same immunological quantity of 'big', 'intermediate' and 'little' ACTH on the release of corticosterone from foetal adrenal glands collected on days 17, 19 and 21 of gestation.…”

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confidence: 99%

“…The 'intermediate' and 'little' forms stimulate the release of corticosterone from perifused adrenal glands removed from 21-day-old foe¬ tuses, but the 'big' form is only weakly active in this respect (Châtelain & Dupouy 1985).…”

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confidence: 99%

The biological activity of different molecular forms of ACTH on corticosterone production by perifused foetal rat adrenal glands in vitro

Chatelain

Cheong²

1987

Acta Endocrinologica

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The responsiveness of perifused adrenal glands removed from rats at various stages of gestation to similar immunological quantities (2 ng) of 'big' ( \ m=cong\ 30 000 mol wt), 'intermediate' ( \ m=cong\ 13 000 mol wt) and 'little' ( \ m=cong\ 4500 mol wt) ACTH isolated by gel filtration chromatography from an acid extract of pituitary glands of 21 day-old rat foetuses was determined. This immunological quantity failed to induce a maximal response of the foetal adrenals. Cortisosterone was determined in the effluent perifusion by a radiocompetition assay. On days 17 and 19 of gestation, intermediate and little ACTH had, on a weight basis, the same corticosteroidogenic activity, but on day 21 the little was more potent than the intermediate form. The corticosterone release by these two forms of ACTH was log-dose dependent. The biological activity of big ACTH was very low on day 17, slightly increased until day 21 but remained significantly lower than that of intermediate and little forms. Big ACTH added to little ACTH in the perifusion medium did not modify the corticosteroidogenic activity of little ACTH on days 17, 19 and 21 of gestation.In vitro investigations have shown that adrenocorticotropic hormone (ACTH 1 -39) and tetracosactin (ACTH 1-24), exert profound trophic and corticosteroidogenic effects on the foetal adrenal glands of many species including the rat (Rudmanetal. 1980;Dupouy 1982).Relatively little is known of the biological activ¬ ity of the other molecular forms of ACTH found in foetal pituitary extracts although Roebuck et al.

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Corticotrophs and Peptides

Schwartz

Revskoy

Redei

et al. 2002

Archives of Physiology and Biochemistry

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Corticotrophs were long thought to be a static, homogeneous population of cells that respond positively to hypothalamic stimulation, are inhibited by glucocorticoid feedback and secrete a single biologically active peptide, ACTH(1-39). Our current understanding is that this is an oversimplification and corticotrophs are a dynamic and more complex group of cells. The biosynthetic precursors of ACTH and other cleavage products of proopiomelanocortin (POMC) have been found to be secreted by anterior pituitary cells, to circulate and to have biological activity. POMC and the biosynthetic intermediate, pro-ACTH, exert activity antagonistic to ACTH(1-39) on glucocorticoid secretion by adrenal cells, and other derivatives of POMC are mitogenic to adrenocortical cells. In terms of responses to hypothalamic and peripheral factors, corticotrophs are functionally heterogeneous. This is reflected in the sensitivity of individual subtypes of corticotrophs to CRH, vasopressin and glucocorticoids. There is a functional plasticity amongst the various types of corticotrophs. During gestation, in fetal sheep, changes occur in the overall ACTH-secretory responses to CRH relative to vasopressin, the proportions of total corticotrophs that respond to the respective peptides and the average secretory response of individual cells. Corticotrophs also respond to locally produced pituitary factors. Local actions of leukaemia inhibitory factor are demonstrated by the effects of immunoneutralization of the peptide in pituitary cells. Urocortin and preproTRH(178-199) are locally produced peptides with potent stimulatory and inhibitory actions on corticotrophs, respectively. The specific roles of these peptides are under investigation.

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Heterogeneity of adrenocorticotrophin in the pituitary gland and plasma during the perinatal period

Abstract: Summary.1) Three immunoreactive forms of ACTH are characterized by their apparent molecular weight (MW)

Cited by 4 publications

References 50 publications

Reduction in Testicular Function in Rats

Reduction in Testicular Function in Rats

The biological activity of different molecular forms of ACTH on corticosterone production by perifused foetal rat adrenal glands in vitro

Corticotrophs and Peptides

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