Seasonal changes in plasma cortisol, testosterone and oestradiol-17β in the plaice, Pleuronectes platessa L

1977 ◽  
Vol 31 (1) ◽  
pp. 1-11 ◽  
Author(s):  
J.C. Wingfield ◽  
A.S. Grimm
Keyword(s):  
Seasonal Changes ◽  
Plasma Cortisol ◽  
Pleuronectes Platessa

Seasonal levels of cortisol and thyroid hormones in intact and castrated mature male white-tailed deer

1984 ◽  
Vol 62 (5) ◽  
pp. 783-787 ◽  
Author(s):  
G. A. Bubenik ◽  
J. F. Leatherland
Keyword(s):  
Thyroid Hormones ◽  
Seasonal Changes ◽  
Plasma Cortisol ◽  
Seasonal Pattern ◽  
Mature Male ◽  
Seasonal Rhythm ◽  
Distinct Peak ◽  
Clear Seasonal Pattern ◽  
Cortisol Levels ◽  
Two Peaks

Plasma L-thyroxine (T4), triiodo-L-thyronine (T3), and cortisol concentrations were measured seasonally in castrated and intact mature white-tailed deer. Both intact and castrated bucks exhibited a statistically significant seasonal rhythm in plasma T4 levels. However, the overall values in the castrated bucks were about 15% lower than in intact animals. Seasonal changes in plasma T3 levels were only found in the intact bucks, with highest values in the April – May period. Two peaks (in June and October) of plasma cortisol were detected in castrated bucks, but only one peak (in the September–October period) was found in intact bucks. In a second experiment in which cortisol levels were measured in "excitable" and "calm" intact bucks, there was no noticeable seasonal rhythm of cortisol in the "excitable" group, but a clear seasonal pattern, with a distinct peak in the October–November period, in the "calm" animals.

Seasonal Changes in the White Blood Cell Population and the Ability of Lymphocytes to Proliferate in Captive Brushtail Possums (Trichosurus vulpecula) .

1999 ◽  
Vol 21 (2) ◽  
pp. 185
Author(s):  
M.L. Baker ◽  
R.T. Gemmell
Keyword(s):  
Blood Cells ◽  
Seasonal Changes ◽  
Plasma Cortisol ◽  
White Blood Cells ◽  
Blood Parameters ◽  
Cortisol Concentration ◽  
Male And Female ◽  
Plasma Cortisol Concentration ◽  
Proliferation Of Lymphocytes ◽  
Cell Mitogen

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.

Spreading the Word: Seasonal Changes Mean New Opportunities for Media Coverage

ASHA Leader ◽  
2013 ◽  
Vol 18 (7) ◽  
Keyword(s):  
Media Coverage ◽  
Seasonal Changes ◽  
Swimming Pools

Summer kicking into high gear conjures images of swimming pools and barbeques. But before you book your beach house for the weekend, think about what the changing seasons can mean for you professionally.

Seasonal changes in a ultraviolet structural colour signal in blue tits, Parus caeruleus

2002 ◽  
Vol 76 (2) ◽  
pp. 237-245 ◽  
Author(s):  
JONAS ORNBORG ◽  
STAFFAN ANDERSSON ◽  
SIMON C. GRIFFITH ◽  
BEN C. SHELDON
Keyword(s):  
Seasonal Changes ◽  
Parus Caeruleus ◽  
Structural Colour ◽  
Blue Tits ◽  
Colour Signal
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