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A. JOSEPHINE MILNER and I. H. MILLS

SUMMARY

Adrenals from foetuses of 13 to 27 weeks gestation were sliced and incubated with 5 μC of [4-14C]progesterone for 2 hr. The biosynthesis of cortisol, 11-deoxycortisol, androstenedione and 11β-hydroxyandrostenedione was estimated by reverse isotope dilution. Cortisol was the major product identified and the production of both cortisol and 11β-hydroxyandrostenedione increased with gestational age in approximate proportion to the increasing adrenal weight. The ratio of (cortisol plus 11-deoxycortisol) to (androstenedione plus 11β-hydroxyandrostenedione) was constant at 13, 16 and 27 weeks gestation. The production of cortisol and androstenedione from progesterone and from pregnenolone by adrenal tissue from a 27-week-old foetus is compared.

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P. J. LEONARD

SUMMARY

Aldosterone secretion is increased in rats on a diet low in sodium content or in rats with nephrosis induced by administration of an aminonucleoside. Distributions of water and sodium in heart, liver, adrenals and abdominal muscle were compared in nephrotic rats, sodium-restricted rats and rats maintained on a normal diet. In nephrotic animals total tissue sodium increased significantly in liver, heart and abdominal muscle and was associated with increased intracellular sodium (both absolute amount and concentration) in these tissues as well as in the adrenals; extracellular sodium decreased in heart and adrenals and increased in abdominal muscle. In nephrotic rats increased total tissue water in liver and abdominal muscle was associated with increased extracellular water while increased total water in adrenals was accompanied by increased intracellular water. The results in sodium-restricted rats were similar to those in nephrotic rats except that no changes were found in abdominal muscle and that water content of liver was unchanged.

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AC McFarlane, SR Edmondson, EM Wintour, and GA Werther

In order to examine the role of GH in the regulation of foetal adrenal development and function, we have localized GH-receptor mRNA and protein in adrenal glands of ovine foetuses at specific stages of gestation. Adrenals from 60-75 day (n=4), 100-110 day (n=4) and 140-145 day (n=3) foetal sheep (term is 145-150 days) and non-pregnant adult animals (n=3) were dissected and fixed. GH-receptor mRNA localization was studied by in situ hybridization using a (35)S-labelled antisense cRNA probe, and protein by immunohistochemistry using a specific monoclonal antibody to the GH-receptor. At all ages studied, GH-receptor mRNA and immunoreactivity could be detected throughout the adrenocortical region. In adult adrenals, GH-receptor mRNA and immunoreactivity were also evident throughout the adrenocortical zone, with the strongest expression confined to a defined region of cells at the interface between the zona glomerulosa and zona fasciculata. Northern blot analysis of 100 day and 140 day foetal adrenals confirmed the presence of a 4.4 kb GH-receptor mRNA transcript, while immunoblotting of foetal adrenals at approximately 110 days of gestation revealed a 55 kDa GH-receptor species. To study the effect of GH on the function and growth of the immature foetal adrenal gland in vivo, chronically catheterized ovine foetuses (n=4), between 100 and 110 days of gestation, were given a pulsatile infusion of recombinant bovine GH (125 microgram/15 min, 24 pulses/24 h) for 72 h. Plasma cortisol and aldosterone levels were compared with age-matched controls receiving saline infusion alone (n=4). It was found that there was no difference in the basal plasma level of cortisol or aldosterone, and that infusion of GH did not alter steroid levels or gross adrenal size and morphology. These studies demonstrate strong expression of the GH-receptor in the developing ovine foetal adrenal cortex. However, in the immature foetus GH infusion is without effect on plasma steroid levels, suggesting that the steroidogenic action of GH in the ovine foetus may be gestationally dependent.

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Irina V Mikhaylova, Tiina Jääskeläinen, Jarmo Jääskeläinen, Jorma J Palvimo, and Raimo Voutilainen

Leukemia inhibitory factor (LIF) is a multiple function cytokine regulating the hypothalamic–pituitary–adrenal axis at the pituitary level. LIF and its receptor are expressed in the adrenal glands, suggesting their potential regulatory role also at the adrenal level. Our aim was to clarify the effects of LIF on adrenal steroidogenesis using cell culture conditions. NCI-H295R human adrenocortical cells were treated with LIF (0.01–100 ng/ml) for 3–48 h with or without 8-bromo-cAMP (8-Br-cAMP; 1 mM). LIF treatment augmented cortisol, dehydroepiandrosterone (DHEA), DHEA sulfate, androstenedione, and aldosterone production (up to 224, 211, 149, 229, and 170% of control respectively, P<0.05 for all). It increased basal steroidogenic acute regulatory protein (STAR) and 17α-hydroxylase/17,20-lyase (CYP17A1) mRNAs (up to 142 and 170% of control respectively, P<0.05) and the respective proteins, but decreased 3β-hydroxysteroid dehydrogenase type 2 (HSD3B2) mRNA (down to 72% of control, P<0.05), and protein. LIF also increased 8-Br-cAMP-induced cortisol and DHEA production and STAR mRNA accumulation, while it attenuated 8-Br-cAMP-induced HSD3B2 expression and androstenedione production. It had an additive effect on tumour necrosis factor-induced cortisol production. LIF had no effect on apoptosis, but it increased slightly the number of metabolically active cells (up to 120% of control, P<0.05). These findings indicate that LIF is a potential physiological and/or pathophysiological regulator of steroidogenesis at the adrenal level.

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C. J. Kenyon, N. A. Saccoccio, and D. J. Morris

ABSTRACT

The effects of constant infusions of small doses of adrenal steroid hormones on sodium, potassium and water metabolism were studied in male adrenalectomized rats. An infusion of 1 μg aldosterone/day was sufficient to restore normal sodium and potassium balance in a group of rats fed an unsupplemented diet. Log doses of aldosterone (0·1–10 μg/day for 4 days) administered some days after adrenalectomy caused linear increases in the body weight of rats fed a sodium-supplemented diet (0·05 m-NaCl as drinking fluid) during 4 days of treatment. Increases in body weight correlated with renal sodium and water balance.

When steroid treatment was started at the time of adrenalectomy, sodium balance was not significantly affected although rats treated with 1 μg aldosterone/day ate more, drank less saline, produced a smaller volume of urine of greater osmolarity and gained more weight than controls. A dose of 100 μg 18-hydroxy-deoxycorticosterone/day had no significant effects. Fluid intake and urine volume were not significantly affected by 1 mg corticosterone/day but food intake, water balance and weight gain were greater than controls. Rats treated with both aldosterone and corticosterone showed a decrease in free water clearance. Aldosterone and corticosterone, both singly and in combination, reduced plasma potassium levels. Plasma sodium levels were only increased when aldosterone was administered on its own.

Long-term steroid infusions have revealed more about the physiology of aldosterone action than could acute measurements of renal function. In particular, they have indicated that dietary intake of electrolytes as well as excretion are affected, that mineralocorticoid actions are distinct from glucocorticoid actions and that there are transient effects of aldosterone on fluid regulation which are not sustained under steady-state conditions.

J. Endocr. (1984) 100,93–100

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E. H. D. CAMERON, M. A. BEYNON, and K. GRIFFITHS

SUMMARY

The ability of cells from the zona fasciculata and the zona reticularis of the human adrenal cortex to transform labelled pregnenolone and progesterone to cortisol in vitro was investigated. Examination of the 3H:14C ratios of 16α-hydroxyprogesterone, 17α-hydroxyprogesterone, 11-deoxycorticosterone and cortisol formed during incubations in vitro suggested that the role of progesterone in the transformation of pregnenolone to cortisol might be a relatively minor one.

An attempt was subsequently made to estimate the relative importance of the biosynthetic pathway to cortisol by way of progesterone in hyperplastic adrenal tissue by a mathematical approach.

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M. M. SHAHWAN, R. E. OAKEY, and S. R. STITCH

SUMMARY

Adrenal tissue from newborn anencephalic infants converted pregnenolone and progesterone to cortisol, 17α-hydroxyprogesterone, corticosterone, 17α,21-dihydroxyprogesterone, deoxycorticosterone and 1 1β-hydroxyprogesterone in vitro. These metabolites were identified by recrystallization to constant specific activity after multiple chromatography and derivative formation. The results demonstrate a potential for corticosteroid biosynthesis, at least from pregnenolone and progesterone, by the adrenals of the anencephalic infant, and therefore possibly by the definitive zone of the adrenal of the normal newborn infant.

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K. GRIFFITHS, D. CUNNINGHAM, and E. H. D. CAMERON

SUMMARY

Tissue from a clear cell adenoma of the adrenal gland was incubated simultaneously with [7α-3H]pregnenolone sulphate and [4-14C]pregnenolone in Krebs—Ringer bicarbonate-glucose solution. Evidence was obtained for the conversion of pregnenolone sulphate to cortisol and corticosterone. The differences in the ability of the tissue to convert the sulphate and the free steroid to corticosteroids and androgens are discussed in relation to theories on the functional zonation of the human adrenal cortex.

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A. T. A. FAZEKAS, J. HOMOKI, W. M. TELLER, and W. GAUS

SUMMARY

The effect of genetic difference (white v. coloured) on the cortisol content of ten different organs and tissues, including the adrenals, of white and coloured guinea-pigs of both sexes and of different ages was studied by protein-binding techniques. Tissue cortisol concentration was significantly higher in all the tissues and adrenals of white animals of both sexes compared with coloured animals. The difference in tissue cortisol content between white and coloured animals was higher before (range 41·5–134·%) than after puberty (range 10·1–82·5%). The age-dependent decrease of cortisol concentration in different tissues and adrenals in adults was more marked in white guinea-pigs of both sexes (mean 30·6%, range 0·0–71·5%) than in coloured (mean 16·9%, range 0·0–63·1%). In adult animals the liver contained significantly 11·8–36·4%) more cortisol than in prepubertal animals. This pattern was the same in white and coloured guinea-pigs of both sexes.

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Annette McKeever, J. A. Oliver, I. W. Henderson, and Warwick Mosley

An angiotensin I-converting enzyme inhibitor (captopril) was given by gastric lavage at a dose of 30 mg/kg body weight per day to Long–Evans rats for a 13-day period during which they received a sodium-deficient diet. This regime was preceded by a 3-day period during which measurements were made on the animals on a sodium-replete dietary intake. Control sodium-deprived rats showed increased plasma renin activities, increased peripheral aldosterone concentrations and reduced urinary sodium excretion; they maintained positive sodium balance and the zona glomerulosa of the adrenal cortex hypertrophied. Captopril-treated sodium-deprived rats failed to reduce urinary sodium excretion sufficiently and entered a period of marked and sustained negative sodium balance. Peripheral aldosterone concentrations after 12 days of sodium deprivation in the presence of captopril treatment were similar to those of sodium-replete rats. The adrenocortical zona glomerulosa of the captopril-treated rats did not increase in size and regressive changes were noted.