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Titolo:
Developmental regulation of corticotrophin receptor gene expression in theadrenal gland of the ovine fetus and newborn lamb: Effects of hypoxia during late pregnancy
Autore:
Fraser, M; Braems, GA; Challis, JRG;
Indirizzi:
Univ Toronto, Dept Physiol, Fac Med, Toronto, ON M5S 1A8, Canada Univ Toronto Toronto ON Canada M5S 1A8 c Med, Toronto, ON M5S 1A8, Canada Univ Toronto, Fac Med, Dept Obstet & Gynaecol, Toronto, ON M5S 1A8, CanadaUniv Toronto Toronto ON Canada M5S 1A8 aecol, Toronto, ON M5S 1A8, Canada Univ Giessen, Dept Obstet & Gynaecol, D-35392 Giessen, Germany Univ Giessen Giessen Germany D-35392 Gynaecol, D-35392 Giessen, Germany
Titolo Testata:
JOURNAL OF ENDOCRINOLOGY
fascicolo: 1, volume: 169, anno: 2001,
pagine: 1 - 10
SICI:
0022-0795(200104)169:1<1:DROCRG>2.0.ZU;2-3
Fonte:
ISI
Lingua:
ENG
Soggetto:
MESSENGER-RIBONUCLEIC-ACID; GROWTH FACTOR-BETA; ADRENOCORTICAL-CELLS; FETAL SHEEP; ANGIOTENSIN-II; ADENOSINE-MONOPHOSPHATE; PROLONGED HYPOXEMIA; LATE-GESTATION; RNA LEVELS; ACTH;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
46
Recensione:
Indirizzi per estratti:
Indirizzo: Challis, JRG Univ Toronto, Dept Physiol, Fac Med, Med Sci Bldg,Room 3205-7,1 Kings CollCircle, Toronto, ON M5S 1A8, Canada Univ Toronto Med Sci Bldg,Room 3205-7,1 Kings Coll Circle Toronto ON Canada M5S 1A8
Citazione:
M. Fraser et al., "Developmental regulation of corticotrophin receptor gene expression in theadrenal gland of the ovine fetus and newborn lamb: Effects of hypoxia during late pregnancy", J ENDOCR, 169(1), 2001, pp. 1-10

Abstract

Responsiveness of the fetal Sheep adrenal gland to adrenocorticotrophin (ACTH) increases in late pregnancy, resulting in increased glucocorticoid production. Development of this responsiveness is an important determinant of fetal hypothalamic-pituitary-adrenal function and depends, in part, on the potential for ACTH binding to adrenal tissue. In the present study, we haveexamined the developmental pattern of ACTH receptor (ACTH-R) expression during the latter half of pregnancy and in neonatal and adult life. As hypoxaemia induces increases in cortisol and ACTH secretion, in addition to increasing fetal adrenal responsiveness, a further aim of this study was to investigate whether hypoxaemia was associated with altered expression of the ACTH-R gene. Whole adrenal glands were removed from fetal sheep, lambs and adult sheep at different stages of development for measurement or ACTH-R mRNA. Moderatehypoxaemia was induced for 48 h beginning on days 124-128, or on days 131-134 of gestation, by decreasing the maternal fractional inspired oxygen. ACTH-R mRNA was detected northern blotting using a cDNA cloned in our laboratory and by in situ bydridisation. ACTH-R mRNA (3.6 kb major transcript) was detected in adrenal tissue at day 63 of gestation. Its relative abundance increased significantly (P<0.05) between days 126-128 and 140-141 of pregnancy, increased further with the onset of spontaneous labour, and remained increased in newborn lambs at 7 h-7 days after birth. ACTH-R mRNA levels then decreased ill adrenal tissue from lambs and adult sheep (P<0.05). Hypoxaemia for 48 h significantly increased ACTH-R mRNA expression in adrenals of the older fetuses (days 134-136) compared with that in controls (P<0.05), but was without effect in younger fetuses. We conclude that levels of ACTH-R mRNA ill the fetal adrenal gland increase as term approaches, coincident with the endogenous prepartum surge in plasma ACTH and cortisol. Sustained hypoxaemia resulted in an upregulation of mRNA encoding for ACTH-R, but only in older fetuses and in association witha sustained increase in plasma cortisol. These results are consistent withcortisol, ACTH, or both, contributing to increased fetal adrenal responsiveness, by increasing expression of fetal adrenal receptors for ACTH.

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Documento generato il 02/04/20 alle ore 05:13:26