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EILEEN A. MICHIE and BARBARA E. CLAYTON

The aim of the present study has been to discover whether the total urinary excretion of neutral 17-ketosteroids is affected by division of the nerves supplying the adrenal glands, with or without complete removal of one adrenal gland.

During treatment for essential hypertension, selected patients undergo bilateral splanchnicectomy resulting in complete section of the nerve supply of the adrenal glands, and in addition right-sided adrenalectomy may be performed. It is thought that in women the urinary 17-ketosteroids are derived from the adrenals only, and that the ovaries probably play no part in their production, since öophorectomy does not significantly alter the excretion [Callow, 1938; Callow, Callow & Emmens, 1940; Fraser, Forbes, Albright, Sulkowitch, Reifenstein, 1941; Ross, Hamblen, Cuyler & Baptist, 1941; Hamblen, Cuyler & Baptist, 1941]. Further, negligibly small assays have been reported in women suffering from Addison's disease [Fraser et al. 1941].

Accordingly two female patients undergoing surgical treatment

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J. P. Hinson, G. P. Vinson, and B. J. Whitehouse

ABSTRACT

The effects of prior sodium depletion on the steroidogenic responses of the rat adrenal gland have been investigated using a method of perfusing the isolated adrenal gland of the rat in situ. Secretion rates of aldosterone in response to the known adrenocortical stimulants ACTH, angiotensin II amide and α-MSH were measured. In each case, the adrenals from sodium-deplete animals responded to a lower dose of the stimulant than the normal animals. This resulted in a 10-fold increase in sensitivity to ACTH, a 100-fold increase in sensitivity to angiotensin II amide, and a 1000-fold increased sensitivity to α-MSH, bringing the threshold concentration required for aldosterone secretion into the physiological range of α-MSH concentrations.

The perfused adrenal gland is particularly sensitive to angiotensin II amide; a bolus administration of 1 amol gave a significant increase in aldosterone secretion in the sodium-deplete group.

These data confirm previous reports of increased adrenal sensitivity to α-MSH and angiotensin II in sodium depletion, and also suggest the existence of intraglandular mechanisms for signal amplification which may be involved in mediating the adrenal response to very small concentrations of stimulant.

J. Endocr. (1988) 119, 83–88

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KT Davis, N Prentice, VL Gay, and SA Murray

Mouse and monkey adrenal glands were used to study the relationships between gap junction protein expression, intercellular communication and adrenal zonation. Dye communication patterns were determined by incubating freshly excised and hemisected adrenal glands in Lucifer yellow, a gap junction permeable fluorescent dye. Immunohistochemical techniques were used to localize adrenal gap junction proteins. The combination of these two techniques permitted the correlation of gap junction proteins with dye transfer and hormone responses in specialized regions of the adrenal cortex. Lucifer yellow dye communication was most pronounced in the inner glucocorticoid/androgen-producing regions (zona fasciculata/zona reticularis), but was virtually absent in the outer mainly mineralocorticoid-producing region (zona glomerulosa). This pattern of dye communication was coincident with immunohistochemical localization of the gap junction protein, alpha(1)Cx43. The variations in communication and alpha(1)Cx43 expression within the adrenal cortex are thought to be relevant to normal physiological regulation of the adrenal gland.

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Duarte Pignatelli, Fang Xiao, Alexandra M Gouveia, Jorge G Ferreira, and Gavin P Vinson

Normal pubertal development in humans involves two distinct processes: maturation of adrenal androgen secretion (adrenarche) and activation of the hypothalamic–pituitary–gonadal axis (gonadarche). One factor thought to contribute to the adrenarche in man is increased adrenal 17-hydroxylase (CYP17) activity. In the rat, there is evidence for adrenal involvement in the initiation of puberty, but the adrenal glands of this species are generally thought to express CYP17 only very poorly at best. To further examine the nature of postnatal adrenal development in rat, plasma samples and adrenal tissues were taken from animals aged 2–90 days, circulating adrenal steroids assayed, and adrenal zones assessed quantitatively. A relative increase in zona reticularis, and peaks of circulating cortisol, androstenedione, and 17-OH-progesterone were observed around postnatal days 16–20, clearly before the development of the gonads, which begins at 30–35 days. Quantitative reverse transcriptase PCR confirmed a peak in mRNA coding for CYP17 in adrenal tissue from rats of similar age. The results suggest that the rat adrenal has the capacity to secrete steroids arising from 17-hydroxylation, and that this may contribute to a process similar to human adrenarche.

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D. S. HART, D. W. BEAVEN, N. C. FRANCE, and E. A. ESPINER

SUMMARY

Sheep with adrenal autotransplants were used to study the direct effect of dexamethasone on the adrenal response to corticotrophin (ACTH).

When the adrenal cortex, under constant ACTH stimulation, was infused with dexamethasone at rates from 9·5 to 41 μg./min., no significant change in cortisol secretion occurred. Since concentrations of dexamethasone as high as 2 to 4 μg./ml. of infusing blood were maintained for up to 70 min., it is concluded that short-term administration of dexamethasone has no important effect on the adrenal sensitivity to ACTH in sheep under physiological conditions.

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J. S. COWAN, G. A. KINSON, and W. J. POZNANSKI

Departments of Physiology and Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Canada, KIN 9A9

(Received 21 September 1976)

In addition to the in-vivo studies on the feedback regulation of the hypothalamic-hypophysial-adrenal axis it is possible to study adrenal cells in isolation to determine to what extent they may be conditioned by certain regulatory defects. This became possible after the development of methods for preparing and maintaining viable suspensions of rat adrenal cells (Swallow & Sayers, 1969). After using a rat adrenal cell suspension method as a sensitive corticotrophin (ACTH) bioassay in this laboratory (Cowan, Davis & Layberry, 1974), the technique has been adapted to study the response of human adrenal cells to ACTH. In this work, the secretory characteristics of cells of the adrenal cortex from four female patients have been determined.

Patient 1 was aged 19, with Cushing's syndrome and pronounced virilization. Plasma cortisol levels before adrenalectomy were

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K. R. VAN KAMPEN and L. C. ELLIS

SUMMARY

Prolonged gestation associated with cyclopia in offspring of ewes ingesting Veratrum californicum is described. In single or multiple pregnancies where all foetuses are cyclopic, foetal hypophysial aplasia, foetal thyroidal and adrenal hypoplasia, and foetal gonadal hypertrophy were associated with prolonged gestation. Cyclopic foetuses that were twins to normal foetuses were delivered at term and, with the exception of hypophysial aplasia, other endocrine organs (thyroid, adrenal and gonads) showed no morphologic abnormalities.

In sheep, during prolonged gestation, comparative studies of the ability of maternal and foetal endocrine glands to synthesize steroids indicated that the foetal ovary was capable of transforming more substrates (pregnenolone and progesterone) into steroid metabolites than the maternal ovary, even though the same group of metabolites is formed by foetal and maternal ovaries. Foetal adrenals produced more testosterone than maternal adrenals, but synthesized very little cortisol, corticosterone and cortisone. Foetal adrenals were incapable of forming water-soluble steroids although the ovaries from cyclopic foetuses and maternal adrenals possessed this capability.

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P. SINGH-ASA, G. JENKIN, and G. D. THORBURN

The effectiveness of trilostane and azastene as inhibitors of adrenal steroidogenesis was compared by in-vitro and in-vivo methods. A radioimmunoassay was developed for the measurement of cortisol in ovine plasma, incubation medium and tissue extract using a specific antiserum raised against cortisol 21-acetate,3-carboxymethyloxime : bovine serum albu

Trilostane (20 μmol/l) decreased cortisol synthesis and release both in unstimulated and in ACTH-stimulated adrenal tissues in vitro. The same concentration of azastene had a lesser effect on unstimulated adrenals and was completely ineffective in blocking the stimulatory action of ACTH. In vivo, trilostane suppressed adrenal steroidogenesis in pregnant and cyclic ewes but the suppression in pregnant ewes was over a longer period, and after lower doses.

It is concluded that trilostane had an inhibitory effect on ovine adrenal steroidogenesis both in vitro and in vivo.

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MAGDA WEISS

SUMMARY

The formation of corticosteroids from [14C]pregnenolone or [14C]progesterone by platypus and echidna adrenal homogenates was studied. Corticosteroids were assayed in the peripheral blood plasma of the platypus. In the platypus nine labelled conversion products were identified. The combined yields of cortisol and cortisone averaged 70% and the combined yields of corticosterone and 11-dehydrocorticosterone averaged 14%. Aldosterone was identified in each experiment in yields below 0·1%. In the echidna ten labelled conversion products were identified. Those in highest yield were 11-deoxycorticosterone and 11-deoxycortisol which contained, respectively, an average of 35 and 11% of the added substrate. The yield of corticosterone was always less than 1% and that of cortisol was consistently lower. Aldosterone was identified in all cases in yields below 0·05%.

The yields of total 11β-hydroxylated conversion products from platypus adrenal exceeded 80%, whereas they were below 1% from glands of male echidnas and 7% from female echidna.

The yield—time curves for labelled conversion products from [14C]-pregnenolone indicated that the biosynthetic pathways of corticosteroid production by the monotreme adrenal are similar to those in eutherian mammals.

From stored endogenous precursors of a platypus adrenal incubated for 30 min, corticosteroids were formed in the following amounts (per 100 mg adrenal): cortisone, 5·1 μg; cortisol, 1·3 μg; 11-dehydrocorticosterone, 1·5 μg. In the peripheral plasma of platypus the concentration of combined cortisol and cortisone was 14 μg/100ml and the combined corticosterone and 11-dehydrocorticosterone was 1·8 μg. The mean ratio of adrenal weight (mg) to body weight (kg) was 39·5 in the echidna and 257 in the platypus. The marked contrast in adrenocortical biosynthetic capacity of the two monotremes is discussed and a comparison of the results is made in relation to higher mammals.

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BARBARA J. WHITEHOUSE, G. P. VINSON, and P. A. JANSSENS

SUMMARY

Incubation of hamster adrenal tissue in Krebs bicarbonate Ringer solution gave rapid conversion of added [4-14C]cortisol to cortisone. Moreover, incubation in Ringer solution with [4-14C]progesterone as precursor invariably yielded cortisone in greater amounts than cortisol. On the other hand it has been confirmed that cortisol is the major free ultraviolet absorbing steroid in the adrenal venous blood of the hamster. Incubation of adrenal tissue with [4-14C]progesterone in hamster whole blood gave relatively greater amounts of cortisol which were more in keeping with the findings in vivo. This suggested that the blood contains factors which affect the cortisone-cortisol equilibrium by modifying adrenal enzyme activity. Some reduction of [3H] cortisone to cortisol was also observed during incubation with blood alone.