Hormone responses to sedative drugs and cold exposure in two rat lines with high and low alcohol sensitivity

1992 ◽  
Vol 41 (4) ◽  
pp. 795-799 ◽  
Author(s):  
E.R. Korpi ◽  
K. Tuominen ◽  
P.T. Männistö
Keyword(s):  
Cold Exposure ◽  
Alcohol Sensitivity ◽  
Hormone Responses ◽  
Sedative Drugs ◽  
Low Alcohol

Effect of iron-deficiency anemia on hormone levels and thermoregulation during cold exposure

1984 ◽  
Vol 247 (1) ◽  
pp. R114-R119
Author(s):  
J. Beard ◽  
W. Green ◽  
L. Miller ◽  
C. Finch
Keyword(s):  
Iron Deficiency ◽  
Cold Exposure ◽  
Hormonal Regulation ◽  
Thyroid Stimulating Hormone ◽  
Cold Sensitivity ◽  
Deficiency Anemia ◽  
Tissue Iron ◽  
Iron Deficient ◽  
Hormone Responses ◽  
O2 Delivery

When exposed to an ambient temperature of 4 degrees C, iron-deficient anemic rats become hypothermic. This lesion is related more to anemia than to tissue iron deficiency, since exchange transfusion to hematocrits over 25 restored normal thermoregulatory performance. Likewise poor cold responses were induced in control rats by transfusion to low hematocrits. Cold sensitivity in all anemic animals was paralleled by poor thyroid responses: there was a significant positive correlation between hematocrit and percent rise in triiodothyronine (r = 0.63) and thyroxine (r = 0.53) during 6 h at 4 degrees C. Basal levels of thyroid-stimulating hormone (TSH) were similar in control and iron-deficient animals: after cold exposure, TSH rose to higher levels in those animals with hematocrits over 25 than in those with lower hematocrits. Diminished O2 delivery to tissues responsible for heat production is probably a major component of the cold sensitivity of anemic rats. The novel finding that thyroid hormone responses are compromised by anemia implies effects on hormonal regulation that may also contribute to this functional lesion.

scholarly journals Thyroid hormone responses to prolonged cold exposure in man

1974 ◽  
Vol 241 (1) ◽  
pp. 175-181 ◽  
Author(s):  
C. J. Eastman ◽  
R. P. Ekins ◽  
I. M. Leith ◽  
E. S. Williams
Keyword(s):  
Thyroid Hormone ◽  
Cold Exposure ◽  
Hormone Responses

scholarly journals Cold-induced dishabituation in rodents exposed to recurrent hypoglycaemia

Diabetologia ◽  
2021 ◽  
Author(s):  
Keeran Vickneson ◽  
Jessica Blackburn ◽  
Jennifer R. Gallagher ◽  
Mark L. Evans ◽  
Bastiaan E. de Galan ◽  
...  
Keyword(s):  
Cold Exposure ◽  
Glucose Clamp ◽  
Adaptive Memory ◽  
Hormonal Responses ◽  
Response Control ◽  
Hormone Responses ◽  
Characteristic Features ◽  
Recurrent Hypoglycaemia ◽  
Study Stimulus

Abstract Aims/hypothesis Recurrent hypoglycaemia in people with diabetes leads to progressive suppression of counterregulatory hormonal responses to subsequent hypoglycaemia. Recently it has been proposed that the mechanism underpinning this is a form of adaptive memory referred to as habituation. To test this hypothesis, we use two different durations of cold exposure to examine whether rodents exposed to recurrent hypoglycaemia exhibit two characteristic features of habituation, namely stimulus generalisation and dishabituation. Methods In the first study (stimulus generalisation study), hyperinsulinaemic–hypoglycaemic (2.8 mmol/l) glucose clamps were performed in non-diabetic rodents exposed to prior moderate-duration cold (4°C for 3 h) or control conditions. In the second study (dishabituation study), rodents exposed to prior recurrent hypoglycaemia or saline (154 mmol/l NaCl) injections over 4 weeks underwent a longer-duration cold (4°C for 4.5 h) exposure followed 24 h later by a hyperinsulinaemic–hypoglycaemic (2.8 mmol/l) glucose clamp. Output measures were counterregulatory hormone responses during experimental hypoglycaemia. Results Moderate-duration cold exposure blunted the adrenaline (epinephrine) response (15,266 ± 1920 vs 7981 ± 1258 pmol/l, Control vs Cold; p < 0.05) to next day hypoglycaemia in healthy non-diabetic rodents. In contrast, the suppressed adrenaline response (Control 5912 ± 1417 vs recurrent hypoglycaemia 1836 ± 736 pmol/l; p < 0.05) that is associated with recurrent hypoglycaemia was restored following longer-duration cold exposure (recurrent hypoglycaemia + Cold 4756 ± 826 pmol/l; not significant vs Control). Conclusions/interpretation Non-diabetic rodents exhibit two cardinal features of habituation, namely stimulus generalisation and dishabituation. These findings provide further support for the hypothesis that suppressed counterregulatory responses following exposure to recurrent hypoglycaemia in diabetes result from habituation. Graphical abstract

Pituitary and peripheral hormone responses to T3 administration during Antarctic residence

1988 ◽  
Vol 254 (6) ◽  
pp. E733-E739 ◽  
Author(s):  
H. L. Reed ◽  
J. A. Ferreiro ◽  
K. M. Mohamed Shakir ◽  
K. D. Burman ◽  
J. T. O'Brian
Keyword(s):  
Cold Exposure ◽  
Human Subjects ◽  
Control Period ◽  
Free T4 ◽  
Total Triiodothyronine ◽  
Serum T3 ◽  
Total Thyroxine ◽  
Hormone Responses ◽  
Oral Doses ◽  
Extremes Of Temperature

Very little is known regarding hormonal adaptation in human subjects who are exposed to the extremes of temperature and light that are found in polar latitudes. We have previously reported a 50% elevation in the serum thyrotropin (TSH) response to thyrotropin-releasing hormone (TRH), a fall in serum total triiodothyronine (T3) and free T3 (fT3), and no change in serum total thyroxine (T4) or free T4 (fT4) after 42 wk of Antarctic cold exposure. To differentiate between central and peripheral mechanisms that may lead to these changes, we report the effect of sequentially increasing oral doses of T3 (Cytomel) on serum T3 and fT3 levels and on the resultant attenuation of the TSH response to TRH in nine men before, during, and after 42 wk residence in Antarctica. Serum T3 values basally and following the administration of 25, 50, and 75 micrograms/day of T3 were lower after 42 wk of cold exposure (151 +/- 4, 160 +/- 8, 189 +/- 10, and 222 +/- 14 ng/dl, respectively, compared with control values of 160 +/- 7, 178 +/- 7, 202 +/- 9, and 251 +/- 19 ng/dl, respectively, P less than 0.05). Likewise, the fT3 values measured after these three increasing T3 doses were also lower after 42 wk of cold exposure. The pituitary response to TRH was attenuated by each T3 regimen (48 +/- 6, 68 +/- 4, and 77 +/- 4% decreases in the control period), and this suppression was not different after 20 and 42 wk of Antarctic residence.(ABSTRACT TRUNCATED AT 250 WORDS)

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