The suppression of cortisol secretion by steroids, and response to corticotrophin in sheep with adrenal transplants

Beaven, D. W.; Espiner, Eric A.; Hart, D. S.

doi:10.1113/jphysiol.1964.sp007373

Cited by 32 publications

(16 citation statements)

References 34 publications

(48 reference statements)

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“…Entry rates in our experiments imply greater stimulation than in McDonald and Reich's animals. However, the evidence that in the sheep stimulation by ACTH produces incremental increases in adrenal output is not good (Beaven, Espiner & Hart, 1964).…”

Section: Discussionmentioning

confidence: 97%

The Rates of Plasma Cortisol Entry and Clearance in Sheep Before and During Their Exposure to a Cold, Wet Environment

Panaretto¹,

Vickery²

1970

Journal of Endocrinology

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Plasma cortisol concentrations and entry rates increased greatly when nine shorn sheep were exposed to cold, wet conditions for periods up to 70 hr.The average entry rate in four of the cold-stressed animals before their rectal temperatures began to fall was 25 \g=m\g./min.,approximately three to four times greater than in the same sheep before exposure (7\ m=. \ 7\g=m\g./min.). The metabolic clearance rates at this time remained unchanged. Plasma cortisol concentration began to increase about 2-3 hr. before the sheeps' rectal temperatures began to fall. The increase continued until concentrations of 100-200 \g=m\g./1. were reached after the sheeps' rectal temperature had fallen. Cortisol entry increased at this time to what may probably be maximal or near maximal rates in the sheep (about 150-200 \g=m\g./min.). Lowered clearance did not appear to contribute substantially to increased plasma cortisol concentrations at rectal temperatures above 34\s=deg\.Since clearance rates did not begin to fall rapidly until rectal temperature fell below about 34\ s=deg\ , cortisol entry during the terminal phase of hypothermia, approximately 76 \g=m\g./min., was very much less than the observed maximum and the high plasma cortisol concentrations measured during this period were residual and sustained by lowered clearance rates.The adrenal cortices and livers of the sheep after severe hypothermia were heavily infiltrated with fat.The effects of shearing alone, studied in a separate experiment, had a transitory effect since plasma cortisol concentrations and entry rates had returned to near their pre-shearing levels by about 27 hr.

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Section: Discussionmentioning

confidence: 97%

The Rates of Plasma Cortisol Entry and Clearance in Sheep Before and During Their Exposure to a Cold, Wet Environment

Panaretto¹,

Vickery²

1970

Journal of Endocrinology

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“…Synacthen. A greater sensitivity can be obtained by measuring cortisol level in venous blood of an adrenal gland transplanted to the neck of the sheep (Beaven et al 1964), although the surgical preparation makes this technique less attractive.…”

Section: Discussionmentioning

confidence: 99%

“…To block endogenous ACTH secretion, 3 mg of the synthetic glucocorticoid Dexafort (dexamethasone phenyl propionate and betamethasone sodium phosphate, 3·2 mg ml -1, Intervet Labs Ltd, Cambridge, U.K.) were injected intravenously (see Beaven et al 1964). Blood samples were taken at regular intervals after injection, to monitor the decline in plasma cortisol level.…”

Section: Changes In Plasma Cortisol Levels In Response To Synacthenmentioning

confidence: 99%

Pattern of Cortisol Release in Sheep following Administration of Synthetic ACTH or Imposition of Various Stressor Agents

Fulkerson¹,

Jamieson²

1982

Aust. Jnl. Of Bio. Sci.

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This paper describes experiments with sheep, in which changes in plasma cortisol, after imposition of various stressor agents, were compared to the changes following administration of synthetic ACTH. The influence of stress associated with shearing, yarding, oestrogen administration (30 Jlg oestradiol benzoate, i.v.), feeding and fasting on the plasma concentration of cortisol was monitored in four mature Merino ewes. They were placed in the experimental environment for 21 days before monitoring began. The ewes were treated in pairs, each pair being visually and acoustically isolated from the other. One pair of ewes was exposed to the particular stress and the remaining pair acted as their own controls. The treatments were reversed 2 days later. In the second part of the experiment, 0, 0'01, 0'1,1'0 or 10·0 i.u. synthetic ACTH were injected as an intravenous bolus, after endogenous secretion had been suppressed by administration of synthetic glucocorticoid. All blood samples were taken via an indwelling jugular catheter. A comparison of cortisol release-estimated from a plot of cortisol in plasma versus time-following imposition of various stressor agents and administration of synthetic ACTH, allowed stress to be defined in terms of synthetic ACTH equivalents. The most severe stress was associated with shearing (0' 84 i. u. synthetic ACTH equivalents), less stress was imposed by yarding and handling (0'45 i.u.), and there appeared to be no effect attributable to feeding, fasting or oestrogen administration. The similarity in the pattern of cortisol release following ACTH administration offers the possibility of defining acute, but not chronic, stress in terms of ACTH equivalents.

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“…1) and care was taken to see that the outflow tube was held at the height of the gland during the sampling procedure: adrenal venous pressures during sampling were found to fall within the range 2-8 mmHg. Previous estimates of adrenal blood flow in conscious animals have been made in transplanted glands in the sheep (McDonald & Reich, 1959;Beavan et al 1964;Espiner et al 1972), or in sheep with lengthy extravascular by-passes (Blair-West et al 1962;Domanski et al 1968). In the former method, section of the splanchnic innervation and prior removal of the contralateral gland, together with radical changes in blood supply associated with revascularization in a carotid-jugular loop, may well combine to alter the normal blood flow characteristics.…”

Section: Discussionmentioning

confidence: 99%

The effects of infusions of synthetic adrenocorticotrophin in the conscious calf

Edwards¹,

Hardy²,

Malinowska³

1974

The Journal of Physiology

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SUI[MARY 1. A technique is described by which the whole of the effluent blood from the right adrenal gland can be collected as required from conscious, unrestrained calves. The technique may be used to measure adrenal blood flow gravimetrically and to compute the output of adrenal hormones under various conditions in the normal calf.2. In a group of seven calves mean cortisol output from the right adrenal gland was found to vary between 20 and 40 ng. kg-' min-' and corticosterone between 6 and 18 ng. kg-' min-' during a 2 hr period, 24 hr after surgery.3. Intravenous infusions of synthetic adrenocorticotrophin (5 ng. kg-' min-') produced a significant increase in the output of both cortisol and corticosterone within 5 min. The output of both hormones rose to maximal values within 10-20 min and mean values of approximately 300 ng . kg-' min' (cortisol) and 120 ng. kg-' min-' (corticosterone) were maintained thereafter for the duration of the infusion (120 min). The output of both steroids fell to values comparable with those observed initially within 45-60 min after the infusion was discontinued.4. These changes in glucocorticoid output in response to adrenocorticotrophin produced a significant rise in the concentration of both cortisol and corticosterone in peripheral plasma. It is noteworthy that the rise in the mean corticosterone concentration in the peripheral plasma was substantially less than that which might be expected from relating the rise in mean plasma cortisol concentration to cortisol output.5. The results of control experiments have eliminated the possibility that the sampling procedure might itself increase steroid output or peripheral plasma concentration. Comparison of results from calves of widely disparate ages (8-38 days) provided no evidence that either the resting A. V. EDWARDS AND OTHERS output of cortisol or corticosterone or the response to adrenocorticotrophin changes with age within the range examined.6. Infusion of adrenocorticotrophin (5 ng . kg-' min') also stimulated an abrupt rise in adrenal blood flow; mean resting flow (210 + 23 ,dl. kg-') increased by approximately 30 % within 5 min and attained peak values (355-365 /zl.kg-1 min-) between 10 and 30 min. Thereafter, adrenal blood flow steadily decreased and then fell rapidly to within the resting range when the infusion was terminated. No significant changes in heart rate or aortic blood pressure occurred during these infusions.7. The results are discussed in relation to those obtained in other species and under differing conditions by other workers.

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The suppression of cortisol secretion by steroids, and response to corticotrophin in sheep with adrenal transplants

Cited by 32 publications

References 34 publications

The Rates of Plasma Cortisol Entry and Clearance in Sheep Before and During Their Exposure to a Cold, Wet Environment

The Rates of Plasma Cortisol Entry and Clearance in Sheep Before and During Their Exposure to a Cold, Wet Environment

Pattern of Cortisol Release in Sheep following Administration of Synthetic ACTH or Imposition of Various Stressor Agents

The effects of infusions of synthetic adrenocorticotrophin in the conscious calf

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