The reproductive cycle of Coregonus lavaretus (L) in Loch Lomond, Scotland, inrelation to seasonal changes in plasma cortisol concentration

1976 ◽  
Vol 9 (2) ◽  
pp. 105-117 ◽  
Author(s):  
J. D. Fuller ◽  
D. B. C. Scott ◽  
R. Fraser
1999 ◽  
Vol 21 (2) ◽  
pp. 185
Author(s):  
M.L. Baker ◽  
R.T. Gemmell

Brushtail possums in our captive colony die more frequently in winter than in summer. The present study examined whether the increased number of deaths in winter is due to a decreased immune response. The number and proportion of white blood cells, the proliferation of lymphocytes in response to the T cell mitogen, phytohaemagglutin (PHA) and the plasma cortisol concentration were determined in six male and six female possums during summer and winter. The total numbers of white blood cells, the numbers of lymphocytes, the proliferation of lymphocytes and the plasma cortisol concentration did not vary significantly between summer and winter. However, significant differences were observed in the numbers of neutrophils and the ratio of lymphocytes to neutrophils (L:N ratio) between the two seasons. The numbers of neutrophils in male and female possums (n=6, P=O.Ol) and 3.15 x 10 /ml (n=6, P=0.04) respectively during winter. The L:N ratio in male and female possums changed from 93:7 (n=6) and 87:12 (n=6) during summer to 78:20 (n=6; P=0.0004) and 65:33 (n=6; P=0.03) respectively during winter. The changes in the blood parameters in possums during winter are similar to those observed in unhealthy possums that subsequently die. These results suggest that possums face more difficult conditions in winter and this may play a role in the greater number of deaths observed at this time of the year.


2010 ◽  
Vol 298 (4) ◽  
pp. L575-L583 ◽  
Author(s):  
Sandra Orgeig ◽  
Tamara A. Crittenden ◽  
Ceilidh Marchant ◽  
I. Caroline McMillen ◽  
Janna L. Morrison

Pulmonary surfactant is synthesized by type II alveolar epithelial cells to regulate the surface tension at the air-liquid interface of the air-breathing lung. Developmental maturation of the surfactant system is controlled by many factors including oxygen, glucose, catecholamines, and cortisol. The intrauterine growth-restricted (IUGR) fetus is hypoxemic and hypoglycemic, with elevated plasma catecholamine and cortisol concentrations. The impact of IUGR on surfactant maturation is unclear. Here we investigate the expression of surfactant protein (SP) A, B, and C in lung tissue of fetal sheep at 133 and 141 days of gestation (term 150 ± 3 days) from control and carunclectomized Merino ewes. Placentally restricted (PR) fetuses had a body weight <2 SD from the mean of control fetuses and a mean gestational PaO2<17 mmHg. PR fetuses had reduced absolute, but not relative, lung weight, decreased plasma glucose concentration, and increased plasma cortisol concentration. Lung SP-A, -B, and -C protein and mRNA expression was reduced in PR compared with control fetuses at both ages. SP-B and -C but not SP-A mRNA expression and SP-A but not SP-B or -C protein expression increased with gestational age. Mean gestational PaO2was positively correlated with SP-A, -B, and -C protein and SP-B and -C mRNA expression in the younger cohort. SP-A and -B gene expression was inversely related to plasma cortisol concentration. Placental restriction, leading to chronic hypoxemia and hypercortisolemia in the carunclectomy model, results in significant inhibition of surfactant maturation. These data suggest that IUGR fetuses are at significant risk of lung complications, especially if born prematurely.


1960 ◽  
Vol 21 (2) ◽  
pp. 171-176 ◽  
Author(s):  
S. SHUSTER

SUMMARY Plasma cortisol concentrations increased after injections of nicotine. This increase was variable and was no greater than that seen after substitution of normal saline for nicotine. Plasma cortisol concentrations did not increase after nicotine in patients with hypopituitarism and after inhibition of corticotrophin release with triamcinolone. It is concluded that the increased plasma cortisol concentration after injection of nicotine was due to non-specific pituitary stimulation associated with the experimental procedure and not due to any direct effect of the nicotine. Nicotine resulted in a similar increase in plasma cortisol in four patients with diabetes insipidus. Neither rapid infusion of hypertonic mannitol nor ingestion of ethanol had a consistent effect on the plasma cortisol concentration. It is therefore concluded that the antidiuretic hormone is not the 'corticotrophin release factor' in man.


1980 ◽  
Vol 8 (5) ◽  
pp. 587-588 ◽  
Author(s):  
JUDITH M. BAKER ◽  
SHEILA L. HANDLEY ◽  
GILL WALDRON ◽  
T. LESLIE DUNN

1974 ◽  
Vol 63 (2) ◽  
pp. 377-387 ◽  
Author(s):  
JACQUELINE PORTHÉ-NIBELLE ◽  
BRAHIM LAHLOU

SUMMARY Plasma cortisol concentrations, measured by competitive protein-binding, were examined in intact and hypophysectomized goldfish (Carassius auratus L.) adapted to fresh water or to 210 mm-sodium chloride solutions. The mean plasma cortisol concentration of freshwater-adapted fish (6·6 ± 1·8 (s.e.m.) μg/100 ml plasma) increased after stress and intraperitoneal injections of mammalian corticotrophin. Hypophysectomy resulted in a reduction in plasma cortisol concentration to about 2 μg/100 ml plasma. Transfer of fish to sodium chloride solutions caused rapid, but transitory increases in the plasma cortisol concentrations in intact, but not in hypophysectomized fish. After 3 days in the sodium chloride solution the cortisol levels were similar to those of control fish kept in fresh water. The plasma concentrations of this corticosteroid in goldfish appear to be unrelated to external salinity, although a 'mineralocorticoid' action of the hormone cannot be excluded.


1979 ◽  
Vol 80 (3) ◽  
pp. 315-319 ◽  
Author(s):  
J. C. MEIJER ◽  
A. A. M. E. LUBBERINK ◽  
A. RIJNBERK ◽  
R. J. M. CROUGHS

The response has been studied in nine dogs with hyperadrenocorticism due to adrenocortical tumours to the administration of dexamethasone, insulin, lysine-vasopressin and tetracosactide by measuring the changes in plasma cortisol concentration. Administration of dexamethasone did not produce a decrease in the plasma concentration of cortisol in any of these dogs. Administration of insulin caused slight increases in the plasma concentration of cortisol in four out of eight dogs. Lysine-vasopressin increased the plasma concentration of cortisol in eight out of nine dogs, three responded supranormally. Eight out of the nine dogs responded to tetracosactide administration, three responded supranormally. It is concluded that in the dog, in contrast to man, the lysine-vasopressin test cannot be used to differentiate between pituitary-dependent hyperadrenocorticism and hyperadrenocorticism due to an adrenocortical tumour. Apparently pituitary ACTH is not completely depleted in dogs with hyperfunctioning adrenocortical tumours.


1967 ◽  
Vol 113 (499) ◽  
pp. 601-605 ◽  
Author(s):  
P. K. Bridges ◽  
M. T. Jones

There have been a number of studies attempting to quantify anxiety under stress, using biochemical measures such as plasma Cortisol concentration and urinary catecholamine excretion as concomitants of the emotional response. A limitation of some of this work has been the lack of predictable and adequate stresses studied, which have included disturbing interviews (Bliss et al., 1956), admission to hospital and anticipation of operation (Mason, 1959), stressful films (Levi, 1965) and hypnotically induced anxiety (Persky et at., 1959).


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