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Search for other papers by I. W. HENDERSON in
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Search for other papers by I. CHESTER JONES in
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SUMMARY
By use of the 'eel tube', it was shown in the freshwater eel that there was a regular net influx (gain) of sodium and a net outflux (loss) of potassium in quiescent animals with steady and normal respiration. Adaptation of eels to distilled water for periods of up to 6 weeks resulted in an increased net extrarenal (gills) uptake of sodium and an increased net loss of potassium when the head of the animal was placed in tap water made up to 600 μmoles Na+.
Stress, injection of cortisol, metyrapone, metyrapone plus betamethasone and aldactone reduced or abolished net sodium gain and had variable effects on net potassium loss. The injection of aldosterone or a potassium chloride solution, but not that of a sodium chloride solution, produced an increased net gain of sodium.
Removal of the corpuscles of Stannius was without demonstrable effect on net sodium and potassium fluxes; they remained within the normal range. Hypophysectomy reduced net sodium gain. Adrenalectomy markedly diminished or abolished net sodium gain with increased potassium loss. Net sodium gain was restored to normal values by injection of aldosterone.
These results are discussed with regard to the homeostatic mechanisms in the euryhaline teleosts.
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Search for other papers by I. W. HENDERSON in
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This paper gives an account of a re-investigation of the work of Groat (1943, 1944). It shows that, apart from animals dying from extraneous causes, the female ground squirrel in anoestrus, some 5 weeks after adrenalectomy, is in good condition, grows, prefers tap-water, and has electrolyte concentrations in blood and muscle similar to those of control animals. In the absence of the adrenals, new tissue appears in the ovaries and, more rarely, in extra-ovarian sites, and reasons are given for considering it to be adrenocortical both in form and function. The origin of this presumptive adrenocortical tissue and the implications of its formation are discussed.
Search for other papers by MARGARET CHRISTIANSON in
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The work was designed to investigate maternal/foetal adrenocortical interrelationships and, in particular, to answer three questions, namely: (i) what are the factors which control the growth of the foetal adrenal gland; (ii) does the foetal adrenal secrete hormones which have a biological action, similar to adult corticosteroids, on water and salt-electrolyte metabolism; and (iii) is the improved health of the adrenalectomized pregnant rat, compared with that of the adrenalectomized non-pregnant rat, occasioned by the presence of foetuses with their adrenals, or by the secretion of progesterone accompanying pregnancy?
Various categories of experimental animals were considered, including the following: normal non-pregnant and pregnant animals; normal and adrenalectomized non-pregnant animals injected with progesterone; pseudopregnant and adrenalectomized pseudopregnant animals; adrenalectomized non-pregnant and pregnant animals and those with the foetuses removed; animals in which ACTH injections were made into adrenalectomized mothers or directly into foetuses; hypophysectomized non-pregnant and pregnant animals; hypophysectomized and adrenalectomized pregnant animals; normal and adrenalectomized mothers with decapitated foetuses.
Adult and foetal body and adrenal weights and foetal pituitary weights were recorded, and the adrenals in both examined histologically. The sodium and potassium content of adult and foetal plasma and muscle, and the water content of muscle, were determined. The variations in body weight and of food and water intakes of animals in the different experimental categories were observed.
It was concluded that enlargement of the foetal adrenal after adrenalectomy of the mother was due to activity of the foetal pituitary. There was no evidence that either normally or under special circumstances the foetal adrenal secreted hormones which influenced water and salt-electrolyte metabolism. The sodium content of foetal plasma followed fairly closely that of maternal plasma in the various groups. The foetal plasma potassium content (which was about twice that of the adult), the foetal muscle sodium content (which was about eight times that of the adult) and the foetal muscle potassium content (which was similar to that of the mother), did not vary greatly, nor did they seem to be conditioned hormonally.
The presence of foetuses in adrenalectomized mothers did not alter the salt-electrolyte changes usually occurring in cortical insufficiency. While progesterone had a beneficial effect on appetite and body weight in adrenalectomized animals, it tended to produce an increased potassium content of muscle but did not change the salt-electrolyte content of plasma, so that the nature of its action is not clear.
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Search for other papers by I. CHESTER JONES in
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SUMMARY
The anatomy and histology of the adrenal glands of the West African lizard (Agama agama L.) and of the common grass snake (Natrix natrix L.) are described.
In lizards, 30 days after hypophysectomy, there was considerable degeneration, with a 60% loss in weight, of the adrenal. The chromaffin cells underwent no histological change. Some cortical cells contained large sudanophilic, Schultz-positive lipid droplets, some nuclei remaining normal, others showing intense basophilia and shrinkage. In other cells, the cytoplasm was reduced to a small acidophilic patch, with pyknotic nuclei. The sodium and potassium contents of the blood and muscle of these hypophysectomized animals were within the normal range.
In snakes, the successive histological stages in the degeneration of the adrenal cortex 9–11, 20 and 30–39 days after hypophysectomy are described. Injection of mammalian ACTH allowed the adrenal to maintain a normal histological appearance in hypophysectomized snakes. In addition, these animals, and normal animals similarly injected, showed degenerative areas in the cortex, attributable to over-stimulation. Injections of cortisone and DCA into unoperated animals were followed by degeneration of the adrenal cortex. After unilateral adrenalectomy, the contralateral adrenal was hypertrophic.
The sodium and potassium contents of blood and muscle, together with the water content of the latter, were obtained in all groups of animals. Despite the histological changes induced in the adrenal cortex by the various experimental procedures, there were no profound changes in the distribution of salt-electrolytes in any of the animals. The sodium content of muscle of normal snakes was about twice the value found in vertebrate muscle in general.
The results are discussed in the light of present-day knowledge of the adrenal cortex in vertebrates, especially of the gland in mammals.
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SUMMARY
Male adult mice, 80 days after hypophysectomy, show approximately the same pattern of sodium and potassium intake and sodium, potassium and water output as normal mice. The healthy remnant of adrenal cortex left after the operation is thought to be responsible for the day-to-day competence of the hypophysectomized animal in salt-electrolyte metabolism. The histology of the cortex is described and it is shown that, with the injection of ACTH, a cortex of normal appearance can be regenerated from the persistent zona glomerulosa of the long-term hypophysectomized mouse.
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Search for other papers by MARGARET H. SPALDING in
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SUMMARY
Male adult rats whose adrenals were enucleated and allowed to regenerate showed in one group normal competence to handle administered water loads, and in another a slow diuresis after this functional test. In the latter case the predisposing factor is cortical insufficiency and not the absence of the medulla. Even those animals with regenerated enucleated adrenals, which gave a normal response to water loads, nevertheless still showed some differences from normal in regard to sodium and potassium metabolism. The histology of the adrenals in the different groups is described.
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SUMMARY
Male adult rats, with established drinking patterns, were given the choice of saline or tap water to drink, immediately after adrenal enucleation. Both saline and water were taken, but by the 6th day after operation the rats had returned to drinking predominantly tap water. The adrenals at this stage showed a small compact cortex, no distinguishable zona glomerulosa, and they appeared to be composed for the most part of cells in 'fascicles'. Adrenalectomized animals chose saline, drinking more and more pari passu with time. Other short-term enucleated animals were injected with ACTH, and the tendency for the regenerating cortex to form in 'fascicles' was very pronounced.
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SUMMARY
The adrenal of male and female rats with persistent diabetes insipidus showed a prominent zona fasciculata and zona reticularis. The zona glomerulosa was narrow or absent.
The results from this and the preceding three papers are here reviewed together. It is concluded that control of salt-electrolyte metabolism cannot be ascribed to the zona glomerulosa. It is probable that the zona fasciculata is reponsible for most of the adrenocortical secretions. The zona glomerulosa is a vegetative back-water of cells, which is able to produce minimal amounts of adrenocortical secretions without stimulation by pituitary hormones, but is only of significance when the latter are absent. Rising amounts of circulating adrenocorticotrophic hormone (ACTH) can transform the zona glomerulosa into actively secreting cells of the zona fasciculata type. After cessation of such activity the zona glomerulosa re-forms, as the amount of ACTH will maintain only a certain volume of zona fasciculata (and zona reticularis) against the rigid limiting inner circumference formed by the medulla; some of the cells derived from the chief area of cell division in the outer part of the zona fasciculata do not mature to cells of the zona fasciculata type, but form zona glomerulosa cells. It is thought that cell migration occurs from the cells of the outer region of the zona fasciculata to the zona reticularis and that this is, normally, a slow process.
Search for other papers by G. P. VINSON in
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SUMMARY
The capacity of the adrenal gland of the mouse to form steroids in vitro, using incubation techniques with [4-14C]progesterone, was investigated. Reasons are given for the identification of two oestrogens, 16-oxooestrone and 17-epioestriol and two adrenocorticosteroids, corticosterone and 20α-hydroxycorticosterone. The presence or absence of the X zone did not appear to influence the relative amounts of oestrogens and adrenocorticosteroids produced. No compounds which could be unequivocally characterized as androgens (C19 steroids) were found.
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SUMMARY
Using incubation techniques, with progesterone as precursor, the capacity of the mouse ovary to form steroids was examined. Ovaries were taken from three groups of mice: (1) immature mice, (2) mature virgin females, (3) primigravid animals. The formation of the following steroids was suggested by the analytical methods used: 16-oxooestrone, 17-epioestriol, 17α-hydroxyprogesterone, 20α-hydroxyprogesterone, androstenedione, testosterone. Yields were very small from the ovaries of immature mice. The yields of oestrogens were greatest from ovaries of mature virgin females and of testosterone from those of pregnant mice. The factors contributing to the disappearance of the X zone of the adrenal gland during first pregnancy are discussed. It is concluded that one major factor is the secretion of testosterone by the ovary of the gravid mouse.
