Changes in circadian rhythm and suppression of the plasma cortisol level after prolonged stress in the sheep

1985 ◽  
Vol 110 (4) ◽  
pp. 540-545 ◽  
Author(s):  
F. Przekop ◽  
E. Stupnicka ◽  
E. Wolińska-Witort ◽  
K. Mateusiak ◽  
B. Sadowski ◽  
...  
Keyword(s):  
Circadian Rhythm ◽  
Cortisol Level ◽  
Plasma Cortisol ◽  
Plasma Cortisol Level ◽  
Diurnal Variations ◽  
Cortisol Response ◽  
Time Of Application ◽  
Prolonged Stress ◽  
Similar Decrease ◽  
Stimulation Of

Abstract. Diurnal variations in the plasma cortisol level were studied in anoestrous, pro-oestrous and pregnant ewes subjected to weak electric stimulation of the forelimbs 9 h daily for 3 consecutive days. In non-pregnant ewes the cortisol level rose on each of the 3 days when the stimulation was applied and then decreased on the day following the stimulation. A similar decrease in plasma cortisol concentrations in pregnant ewes appeared on the second day of footshocking. The acrophase of the circadian rhythm on electrostimulation days was synchronous with the time of application of footshocks; therefore, in stimulated ewes it was significantly accelerated compared to the prestimulatory day. A decrease in the plasma cortisol level in pro-oestrous and pregnant ewes was accompanied by disappearance of its normal rhythmicity. Since a normal plasma cortisol response to exogenous corticotrophin was noted after 3 days of foot-shocking it seems unlikely that the decrease in the cortisol level after prolonged stress was caused by exhaustion of the adrenal cortex. Some central mechanisms which could account for the biphasic changes in the plasma cortisol level and for disturbances of the hormone diurnal rhythmicity under conditions of prolonged stress are discussed.

The effect of 6-hydroxydopamine infused into the third cerebral ventricle on the plasma cortisol concentration in sheep subjected to repeated and prolonged stress stimuli

1985 ◽  
Vol 110 (4) ◽  
pp. 546-552 ◽  
Author(s):  
E. Domański ◽  
E. Stupnicka ◽  
F. Przekop ◽  
E. Wolińska-Witort
Keyword(s):  
Circadian Rhythm ◽  
Cortisol Level ◽  
Plasma Cortisol ◽  
Plasma Cortisol Level ◽  
Cortisol Concentration ◽  
Cortisol Secretion ◽  
The Third ◽  
Plasma Cortisol Concentration ◽  
6 Hydroxydopamine ◽  
Prolonged Stress

Abstract. It has previously been observed that sheep subjected to repeated and prolonged stress stimuli showed biphasic cortisol responses. On the first and second day of stimulation an elevation was observed, while on the subsequent days and on the day after the stimulation a marked suppression of plasma cortisol level and a disappearance of its circadian rhythm was noted. It was hypothesized that these changes in the secretion of the hormone were caused by the alteration of catecholaminergic systems in the CNS. To verify this suggestion chemical lesions of the catecholergic systems of the diencephalon were carried out by the infusion of 6-hydroxydopamine (6-OHDA) into the third cerebral ventricle and animals treated in this fashion were subjected to repeated and prolonged electrical mild footshocking (applied during 3 days). The pretreated animals lost the circadian rhythm in cortisol secretion on the days before as well as during and after the electrical stimulation. The animals pretreated with 6-OHDA showed a significant rise of the plasma cortisol level during stimulation. This rise, as the highest daily concentration, occurring within about 1 h after the beginning of footshocking, was significantly accelerated in time with respect to the physiological acrophase, occurring in the early morning hours at the end of prestimulatory days. On the other hand, the pretreated animals did not show the decrease of plasma cortisol levels on the day after the stimulation, observed in normal non-pretreated ones. It is suggested that the absence of the suppression of plasma cortisol concentration in the animals pretreated with 6-OHDA on the day after the stimulation may be due to the blockade of the ventral noradrenergic bundle innervating the medial basal hypothalamus, while disappearance of the circadian rhythm of cortisol secretion was due to the disturbance in the function of retinohypothalamic projection.

scholarly journals Circadian Rhythm of the Plasma Cortisol Level in Cases of Prolonged Coma

1977 ◽  
Vol 123 (1) ◽  
pp. 33-47 ◽  
Author(s):  
HIDEYA OKUYAMA ◽  
MINORU ENDO ◽  
YOSHIRO OHARA ◽  
SADAO TAKASE ◽  
KATSUYA ITAHARA
Keyword(s):  
Circadian Rhythm ◽  
Cortisol Level ◽  
Plasma Cortisol ◽  
Plasma Cortisol Level ◽  
Prolonged Coma

STIMULATION OF CARP INTERRENAL FUNCTION BY ADRENOCORTICOTROPHIN

1976 ◽  
Vol 68 (1) ◽  
pp. 13-20 ◽  
Author(s):  
Z. ILAN ◽  
Z. YARON
Keyword(s):  
Protein Binding ◽  
Cortisol Level ◽  
Plasma Cortisol ◽  
Plasma Cortisol Level ◽  
Cortisol Concentration ◽  
Transient Rise ◽  
Competitive Protein Binding ◽  
Cortisol Release ◽  
Stimulation Of

SUMMARY The effect of ACTH on cortisol concentration in the plasma of the carp has been studied; cortisol was determined using a competitive protein-binding radioassay. Blood was sampled at 12.00 h (the diurnal minimum) by cardiac puncture. The plasma cortisol level of undisturbed carp (blood obtained 1–3 min after netting) was 46 ± 14 (s.e.m.) ng/ml. One hour after injection of ACTH (1·0 i.u./100 g body wt., i.m.) the level of cortisol increased to 415 ± 62 ng/ml and reached a maximum of 656 ± 62 ng/ml after 2 h. The level of cortisol in saline-injected control carp after 2 h was 72 ± 33 ng/ml. A transient rise of cortisol was noted in both groups 30 min after injection (315 ± 51, 315 ± 62 ng/ml). This was attributed to a surge of endogenous ACTH, presumably due to handling. Carp head kidneys were superfused in vitro. They released cortisol spontaneously, but the releasing rate declined exponentially and reached a minimum after 135 min. Addition of ACTH to the medium was followed by a prompt increase in cortisol release. The rate of cortisol release was maximal 30–45 min after addition of ACTH and was identical to the rate at the beginning of the superfusion.

Plasma Cortisol Response to Insulin and Circadian Rhythm in Diabetic Subjects

Diabetes ◽  
1968 ◽  
Vol 17 (3) ◽  
pp. 124-126 ◽  
Author(s):  
M. Serio ◽  
B. Tarquini ◽  
P. Contini ◽  
A. Bucalossi ◽  
R. Toccafondi
Keyword(s):  
Circadian Rhythm ◽  
Plasma Cortisol ◽  
Cortisol Response
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