519 Horm. Metab. Res. 9 (1977) 519
© Georg Thieme Verlag Stuttgart Effect of Cold Exposure on a-MSH and ACTH Release in the Rat R. Usategui, P. Gillioz and C. Oliver Laboratoire de Medecine Experimentale, UER Medecine Nord, Marseille, France
Cold exposure has been shown to alter the release of pituitary hormones in the rat. Enhanced release of TSH (Ducommun, Sakiz and Guillemin 1966) and ACTH, as shown indirectly by corticosterone determination (Kokka, Garcia, George and Elliott 1972) has been reported whereas GH declined (Kokka et al. 1972). This report describes changes in plasma a-MSH and ACTH after cold exposure in the rat. Methods
Results and Discussion Plasma a-MSH was significantly lowered throughout the 120 min interval of cold exposure (Experiment A). In the same experiment, a six-fold increase of ACTH was observed at 15 min, followed by a decline to basal values. (In groups of resting rats kept at room temperature, plasma ACTH levels ranged between 85 ± 21 and 155 ± 61 pgjml). In the experiment B, a significant fall of plasma Cl:-MSH was observed after 15 min of cold exposure; however, Cl:-MSH quickly returned to basal levels when the rats were placed again in a warm room. The pattern of ACTH release was not different from that observeu during the first experiment. Table. Effect of cold exposure on plasma a-MSH and ACTH (pgjml; means ± S.E.M.). In the experiment A, the rats were placed in the cold room from time 0 to 120 min. In the experiment B, the rats were placed in the cold room from time 0 to 15 min and returned to a room maintained at 22°C from tine 15 to 120 min. Time (min) First experiment (A) n
0
15
60
30
120
=7
a-MSH
64
ACTH
90
Second experiment (B) n
±6 ± 11
14 523
± 1* ± 90*
178
± 2* ± 81
92
44 140
± +
10 28
69 207
19
13
± 1* ± 62
21 272
± 4* ± 128
=6
31 ± 2* 72 ± 9 a-MSH 101 ± 18 ACTH 568 ± 78** * p 0.001 significantly different compared with time O. ** p
© Georg Thieme Verlag Stuttgart Effect of Cold Exposure on a-MSH and ACTH Release in the Rat R. Usategui, P. Gillioz and C. Oliver Laboratoire de Medecine Experimentale, UER Medecine Nord, Marseille, France
Cold exposure has been shown to alter the release of pituitary hormones in the rat. Enhanced release of TSH (Ducommun, Sakiz and Guillemin 1966) and ACTH, as shown indirectly by corticosterone determination (Kokka, Garcia, George and Elliott 1972) has been reported whereas GH declined (Kokka et al. 1972). This report describes changes in plasma a-MSH and ACTH after cold exposure in the rat. Methods
Results and Discussion Plasma a-MSH was significantly lowered throughout the 120 min interval of cold exposure (Experiment A). In the same experiment, a six-fold increase of ACTH was observed at 15 min, followed by a decline to basal values. (In groups of resting rats kept at room temperature, plasma ACTH levels ranged between 85 ± 21 and 155 ± 61 pgjml). In the experiment B, a significant fall of plasma Cl:-MSH was observed after 15 min of cold exposure; however, Cl:-MSH quickly returned to basal levels when the rats were placed again in a warm room. The pattern of ACTH release was not different from that observeu during the first experiment. Table. Effect of cold exposure on plasma a-MSH and ACTH (pgjml; means ± S.E.M.). In the experiment A, the rats were placed in the cold room from time 0 to 120 min. In the experiment B, the rats were placed in the cold room from time 0 to 15 min and returned to a room maintained at 22°C from tine 15 to 120 min. Time (min) First experiment (A) n
0
15
60
30
120
=7
a-MSH
64
ACTH
90
Second experiment (B) n
±6 ± 11
14 523
± 1* ± 90*
178
± 2* ± 81
92
44 140
± +
10 28
69 207
19
13
± 1* ± 62
21 272
± 4* ± 128
=6
31 ± 2* 72 ± 9 a-MSH 101 ± 18 ACTH 568 ± 78** * p 0.001 significantly different compared with time O. ** p
