Adrenosympathetic overactivity under conditions of work stress.
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Serial measurements of urinary adrenaline, noradrenaline, and 11-hydroxycorticosteroid excretion were performed on 32 healthy men under two conditions of work stress; piecework and work on assembly line. A statistically significant increase in adrenaline, noradrenaline, and 11-hydroxycorticosteroids was observed for piecework and assembly line workers compared with salaried and 'ordinary' workers. The results support the assumption that psychosocial factors of an everyday type have significant effects on the sympathoadrenomedullary and adrenocortical function. (+info)
The factors controlling stem cell recirculation. II. ACTH-induced inhibition of migration of hemopoietic stem cells.
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Injections of ACTH of prolonged action (twice 1.5 units per mouse) given to lethally (800 R) irradiated mice with a hind limb shielded to the middle of the tibia brought about a twofold decrease in the number of spleen colonies. ACTH injections after sublethal whole-body irradiation (600 R) did not affect the number of endogenous spleen colonies. ACTH injection of normal mice brought about a substantial decrease in the CFU content in the circulating blood at the time of increased 11-hydroxycorticosteroid concentrations in the plasma. The results obtained are interpreted as inhibition of CFU migration from a shielded area of bone marrow induced by a high 11-hydroxycorticosteroid content in the plasma that followed ACTH injections which had no mitostatic effect on CFU proliferation. (+info)
Adrenal function in 23 children with paracoccidioidomycosis.
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Adrenal involvement by Paracoccidioides brasiliensis was described at necropsies and in many clinical studies, but only in adults. Therefore, the aim of this study was to evaluate adrenal function in children with paracoccidioidomycosis. Twenty-three children with the systemic form of paracoccidioidomycosis were evaluated and divided in two Groups: Group A (n = 8) included children before treatment and Group B (n = 15) children after the end of treatment. Plasma cortisol (basal and after ACTH test), ACTH, renin activity, aldosterone, sodium and potassium were measured. They were within normal range in all cases, except for renin activity and aldosterone, which were elevated in some cases. Group A patients showed basal and post-ACTH cortisol levels significantly greater than Group B patients. The results showed that adrenal function was not compromised in these children with paracoccidioidomycosis. (+info)
Cushing's syndrome due to huge adrenocortical multinodular hyperplasia.
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A case of Cushing's syndrome due to huge adrenocortial multinodular hyperplasia who was shown to be hyperresponsive to ACTH administration, unresponsive to metyrapone administration and resistant to dexamethasone high dose suppression was reported. After two years' duration of his symptoms, the multinodular adrenals weighing 161 g in total were removed by bilateral adrenalectomy which abolished his symptoms. Postoperatively, plasma ACTH rose gradually to above normal levels, suggesting the presence of primary disorder in the hypothalamus-pituitary axis. (+info)
Precocious development of UDP-glucuronyltransferase activity in chick-embryo liver after administration of adrenocorticotropic hormone and of certain 11beta-hydroxy corticosteroids.
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1. Precocious development of UDP-glucuronyltransferase (EC 2.4.1.17) and of glucuronidation by endogenous compounds of known chemical composition is reported for the first time. 2. This development occurs precociously in chick-embryo liver after administration to the egg of mammalian adrenocorticotropic hormone, of Synacthen (a synthetic compound possessing adrenocorticotropic activity), or of certain corticosteroids possessing a hydroxy or an oxo group at C-11. 3. Corticosterone-dependent transferase development parallels the rise of infused corticosterone in plasma, but does not require the presence of embryo pituitary in ovo, and is demonstrable in embryo liver explants in vitro. 4. Competence of embryo liver transferase to respond to corticosterone (or dexamethasone) begins over days 13-14, the time of competence to respond to grafted pituitary gland. 5. The transferase appearing after treatment with corticosterone or adrenocorticotropic hormone, like that appearing after pituitary grafting or on natural development and unlike that from the untreated embryo, is markedly activated by membrane-perturbation procedures, suggesting it appears through induction, not activation. 6. Thyroxine and tri-iodothyronine accelerate transferase development after treatment with adrenocorticotropic hormone or corticosteroid to the rate seen after pituitary grafting. 7. A wide range of other hormones and steroids did not obviously influence transferase development in this system. 8. We suggest that grafted pituitary gland evokes precocious transferase development in embryo liver through production of adrenocorticotropic hormone and hence of the active corticosteroids; thyrotropin and thyroxine hasten the process. The role of this mechanism in the natural development of UDP-glucuronyltransferase is discussed. (+info)
Comparison of corticotrophin and corticosteroid response to lysine vasopressin, insulin, and pyrogen in man.
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Plasma corticotrophin (ACTH) and corticosteroid levels in response to lysine vasopressin (LVP), insulin hypoglycaemia, and pyrogen have been compared in seven subjects with normal pituitary adrenal function. Intramuscular vasopressin was a weak stimulus to corticotrophin release, peak values lying within the range 49 to 141 pg/ml. Insulin hypoglycaemia consistently caused a more noticeable increase, with peak levels between 114 and 364 pg/ml, while pyrogen was the most powerful, corticotrophin levels rising to between 209 and 1,725 pg/ml. Peak plasma corticosteroid levels showed less pronounced differences between the three tests, and correlated poorly with peak ACTH levels. Thus, relatively small acute changes in corticotrophin levels produce near-maximal adrenal stimulation. Under these conditions, plasma corticosteroid measurements do not accurately reflect circulating corticotrophin levels. These findings help to explain the physiological basis of several observations on the corticosteroid responses to these clinical test procedures. (+info)
Effects of metoclopramide and bromocriptine on the renin-angiotensin-aldosterone system in man. Dopaminergic control of aldosterone.
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This study was designed to investigate the possible role of dopaminergic mechanisms in the control of the renin-angiotensin-aldosterone system in normal man. Six normal male subjects in metabolic balance at 150 meq sodium, 60 meq potassium constant intake received the specific dopamine antagonist, metoclopramide, 10 mg i.v. or placebo followed by angiotensin II infusion 1 h later on 2 consecutive days. Metoclopramide increased plasma aldosterone concentration from 8.2+/-2.2 to 21.0+/-3.3 ng/100 ml (P < 0.005) and plasma prolactin concentration from 18.0+/-4.0 to 91.7+/-4.0 ng/ml (P < 0.001) within 15 min of its administration. At 1 h, plasma aldosterone and prolactin concentrations remained elevated at 16.8+/-2.1 ng/100 ml (P < 0.01) and 86.8+/-15.9 ng/ml (P < 0.005), respectively. Angiotensin II at 2, 4, and 6 pmol/kg per min further increased plasma aldosterone concentration to 27.2+/-3.4, 31.9+/-5.7, and 36.0+/-6.7 ng/100 ml (P < 0.02), respectively. Placebo did not alter plasma aldosterone or prolactin concentrations, but angiotensin II increased plasma aldosterone concentration to 13.7+/-2.4, 19.0+/-1.9, and 23.3+/-3.2 ng/100 ml (P < 0.005). The increment of plasma aldosterone concentration in response to angiotensin II was similar after metoclopramide or placebo. The six subjects also received the dopamine agonist, bromocriptine, 2.5 mg or placebo at 6 p.m., midnight, and 6 a.m. followed by angiotensin II infusion on 2 consecutive d. Bromocriptine suppressed prolactin to <3 ng/ml. After placebo, plasma aldosterone concentration increased from 5.2+/-1.4 to 12.3+/-1.7, 17.2+/-2.2, and 21.8+/-3.5 ng/100 ml (P < 0.01) and after bromocriptine from 7.2+/-1.0 to 14.7+/-3.0, 19.8+/-3.2, and 23.4+/-1.6 ng/100 ml (P < 0.001) with each respective angiotensin II dose. No difference in the response to angiotensin II after bromocriptine or placebo was observed. Plasma renin activity, free 11-hydroxycorticoid concentration, and serum potassium concentration were unchanged by metoclopramide or bromocriptine. The results suggest that aldosterone production is under maximum tonic dopaminergic inhibition which can be overridden with stimulation by angiotensin II in normal man. (+info)
The circadian rhythms of human subjects without timepieces or indication of the alternation of day and night.
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1. Seven solitary subjects, and two groups of four, spent from 5 to 13 days in an isolation unit without knowledge of time. Three solitary subjects and one group of four adopted fairly regular activity habits with a period of 25-27 h; one subject adopted a period of 30 h, and one of 27 h initially, decreasing to 24-25 h after a few days. One group of four awoke roughly every 24 h, after a sleep which was alternately about 8 h, or about 4 h and believed by the subjects to be an afternoon siesta. Two solitary subjects alternated sleeps of about 8 or 16 h, separated by 24 h of activity.2. Deep temperature in all subjects oscillated with a period of 24-26 h, which was thus commonly distinct from their activity habits.3. Urinary potassium followed a rhythm whose period, though usually close to, was sometimes distinct from, that of temperature. A secondary period corresponding to that of activity was also sometimes present.4. Urinary sodium and chloride usually gave evidence of two periodic components, one corresponding to activity and the other to the rhythm of either temperature or of urinary potassium.5. Urinary creatinine and phosphate usually followed the subject's routine of activity.6. Plasma samples were collected on a few occasions and analysed for phosphate and 11-hydroxycorticosteroids. Changes in plasma phosphate were usually, but not always, associated with similar changes in urinary phosphate, and changes in plasma corticosteroids were often, but not always, associated with similar changes in urinary potassium shortly afterwards.7. Observations are recorded on a subject alone in a cave for 127 days. His activity habits, though wildly variable, gave evidence of a period of 25.1 h and his urinary electrolyte excretion indicated a shorter period, of 24.6 h. During the following 3 days, when he remained in the cave but was visited frequently, his plasma corticosteroids and urinary potassium oscillated with a period of 16 h.8. The possible mechanisms controlling these rhythms are discussed. (+info)