Adrenocortical Function in the Horse

James, V. H. T.; Horner, Marian W.; Moss, Michael; Rippon, A. E.

doi:10.1677/joe.0.0480319

Cited by 96 publications

(29 citation statements)

References 35 publications

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“…4B), a response greater than that previously reported in normal horses to similar doses of ACTH (6,10).…”

Section: Acth Stimulation Testmentioning

confidence: 54%

“…The following tests were performed: 1) single dose dexamethasone suppression test (6): dexamethasone (40 jug/kg BW) was injected at 2400, and plasma cortisol was determined at 0800 and 1200 h; 2) two day dexamethasone suppression test: dexamethasone (10 jug/kg BW) was injected im every 6 h for eight doses, and plasma ACTH was determined at 0800 h after the last dose; 3) ACTH stimulation test (6): ACTH (1 IU/kg BW) was injected iv, and plasma cortisol was determined at 0, 60, and 120 min; 4) glucose tolerance test (7): glucose (0.5 g/kg BW) was injected iv, and plasma glucose was determined at 0, 15, 30, 60, 90, 120, 150, and 180 min.…”

Section: Methodsmentioning

confidence: 99%

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A Case of Pituitary Adrenocorticotropin-Dependent Cushing's Syndrome in the Horse*

et al. 1979

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In the horse, a syndrome of hirsutism, hyperglycemia, glucosuria, polydipsia, polyuria, polyphagia, and progressive debilitation has been recognized. Most often the syndrome has been associated with adenomas of the pars intermedia of the pituitary and bilateral adrenal hyperplasia or nodular hyperplasia involving primarily the zona fasciculata. Previously, the syndrome has been ascribed to compression of the hypothalamus by an expanding but functionally inactive pituitary neoplasm. In the present case, with RIA determination of plasma ACTH concentrations, the syndrome was ascribed to pituitary ACTH-dependent hyperadrenocorticism and likened to human Cushing's disease.

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“…4B), a response greater than that previously reported in normal horses to similar doses of ACTH (6,10).…”

Section: Acth Stimulation Testmentioning

confidence: 54%

Section: Methodsmentioning

confidence: 99%

A Case of Pituitary Adrenocorticotropin-Dependent Cushing's Syndrome in the Horse*

et al. 1979

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“…A daily glucocorticoid rhythm has also been described in other mammalian species, such as pigs (Andersson et al, 2000;Whipp et al, 1970), horses (Irvine and Alexander, 1994;James et al, 1970), monkeys , hamsters (de Souza and Meier, 1987), and voles (Kramer and Sothern, 2001). The lowest concentrations are found during rest and a rapid rise occurs just before the beginning of the active period both in day-active and nocturnal species.…”

Section: Introductionmentioning

confidence: 81%

Serum Cortisol Levels in Goats Exhibit Seasonal But Not Daily Rhythmicity

Alila-Johansson

Eriksson

Soveri³

et al. 2003

Chronobiology International

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The aim of the study was to find out whether there is a daily rhythm in goat serum cortisol concentrations, whether the concentration profiles differ between normal light:dark and constant dark conditions, and whether any seasonal variations might be detected in daily cortisol secretion patterns. Seven Finnish landrace goats were kept at indoor temperature (18-23 degrees C) under artficial lighting that approximately simulated the annual changes of daylength at 60 degrees N. Blood samples were collected for cortisol measurements by radioimmunoassay at 2h intervals during six times of the year: winter (light:dark 6:18h), early spring (10:14h), late spring (14:10h), summer (18:6h), early fall (14:10h), and late fall (10:14h). Cortisol profiles were determined for two consecutive days, first in light:dark (LD) conditions and then in continuous darkness (DD). There was no significant daily rhythm in serum cortisol levels in any time of the year, nor did the profiles in LD and DD conditions show any differences. A significant seasonal variation was, however, detected among the overall cortisol levels. In winter, the concentrations were higher than in any other season, and from early spring to summer they were at their lowest. Under equal photoperiods, the cortisol levels were higher in fall than spring. The difference between winter and summer was confirmed the following year in LD conditions. There was on correlation between serum cortisol and progesterone levels. The results suggest that the possible circadian variation of cortisol secretion in goats is completely masked by external factors, and lighting conditions do not have immediate effects on the daily secretion patterns. The seasonal variation in the overall cortisol levels is most probably related to the changes in photoperiod, because other conditions were relatively constant during the experiment.

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“…It is also poss-ible, that the cortisol concentration in plasma of resting horses does not allow their performance capacity to be determined, and an adaptation would only have been demonstrable evaluating the response to standardized exercise. Another approach could have been to measure the response to the application of ACTH (James et al 1970;Rossdale et al 1982;Linden et al 1991a;Golland et al 1996). However, this method may not be readily applicable to sound sport horses, and may be more appropriate for the diagnosis in horses not performing at the expected level.…”

Section: Discussionmentioning

confidence: 99%

“…This is the opinion of many authors (Evans et al 1977;Thornton 1985;Wilson et al 1991). However, in most studies only one blood sample is taken in resting horses (Baker et al 1982;, and after exercise (James et al 1970;Grosskopf et al 1983;Snow et al 1983;Desmecht et al 1996), or more than 15 minutes are within two blood samples (Rossdale et al 1982;Garcia and Beech 1986;Church et al 1987;Freestone et al 1991).…”

Section: Discussionmentioning

confidence: 99%

Plasma cortisol concentration in Thorougbred horses during and after standardized exercise tests on a treadmill and effect of conditioning on basal cortisol values

Lindner¹,

Fazio²,

Medica³

et al. 2000

PHK

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SummaryThe behaviour of cortisol concentration in plasma of clinically normal horses performing two different exercise tests on a treadmill was investigated to study the possible value of measuring cortisol for performance diagnosis. In addition, the horses were exercised with different conditioning programmes and their effect on basal plasma cortisol concentration was measured. Finally, the repeatability of the cortisol values measured before and after exercise were examined. Horses were always exercised on a treadmill. The multiple step exercise test consisted of five gallop workouts lasting five minutes´ each. The velocity in the first step was 6.0 m/s. Each consecutive step velocity was increased by 0.5 m/s. The two-speed exercise test consisted of two runs. In the first run horses were galloped over 1,200 m at a constant velocity of 10, 10.5 or 11 m/s. Thereafter horses were walked for 30 minutes. The second run over 1,200 m was conducted at speeds of 13, 13.5 or 14 m/s. Each conditioning programme examined consisted of eleven repetitions of exercise of 5, 15 or 25 minutes´ duration at a velocity at which, mathematically, horses had a blood lactate concentration of 2.5 or 4 mmol/l. During the multiple step test the mean cortisol concentration in plasma showed a tendency to increase (p = 0.07). The mean peak of the cortisol concentration in plasma was measured 10 minutes after the test. Thereafter mean cortisol concentration continuously decreased and the day after the test values were similar to those before the test. After the first run of the two-speed test mean plasma cortisol concentration tended to increase (p = 0.08), while significant changes were registered after the second run (p < 0.01): It decreased up to the fifth minute after exercise (p < 0.05) and increased threreafter reaching a plateau between the 15th and 45th minute after exercise (p < 0.05). The morning after the test mean plasma cortisol concentration had returned to the values measured the morning before the test. None of the conditioning programmes had an effect on the mean plasma concentration of cortisol in the horses at rest. The mean coefficient of variation of plasma cortisol concentration in five horses before exercise was 34.1% and 36.4% after exercise. The large individual variability of plasma cortisol concentrations before and after exercise does not allow a good repeatability of results, and enforces the need for multiple blood sampling during exercise. The multiple step exercise test as well as the two-speed exercise test induced increases of the plasma cortisol concentration after exercise. The changes measured supply a basis for studies on treadmills on the value of monitoring the plasma cortisol concentration of sport horses for performance diagnosis. Keywords:horse, exercise, cortisol, blood plasma, lactate

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Adrenocortical Function in the Horse

Cited by 96 publications

References 35 publications

A Case of Pituitary Adrenocorticotropin-Dependent Cushing's Syndrome in the Horse*

A Case of Pituitary Adrenocorticotropin-Dependent Cushing's Syndrome in the Horse*

Serum Cortisol Levels in Goats Exhibit Seasonal But Not Daily Rhythmicity

Plasma cortisol concentration in Thorougbred horses during and after standardized exercise tests on a treadmill and effect of conditioning on basal cortisol values

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