TY - JOUR
T1 - Inhibition of corticotropin release during hypothermia
T2 - The role of corticotropin-releasing factor, vasopressin, and oxytocin
AU - Gibbs, Daniel M.
PY - 1985
Y1 - 1985
N2 - To investigate the mechanism by which ACTH secretion is inhibited during hypothermia, hypophysial portal blood was collected from euthermic and hypothermic rats, and the concentrations of corticotropin-releasing factor (CRF), vasopressin (AVP), and oxytocin (OT) were measured by RIA. Whereas CRF levels in portal plasma were not different in the two groups, AVP and OT levels were significantly lower in hypothermic rats. The concentration of AVP and OT in peripheral plasma was also significantly lower in hypothermic rats compared with euthermic controls. The pituitary responsiveness to CRF during hypothermia was tested in vivo and in vitro. In pentobarbital-anesthetized male rats injected iv with 0.1 or 1.0 nmol CRF, the ACTH response was significantly smaller in hypothermic compared with euthermic animals. However, hemipituitaries superfused at 31 C released the same amount of ACTH in response to 1 nM CRF as hemipituitaries superfused at 37 C (31 C, 541 ± 90 pg; 37 C, 563 ± 29 pg) despite reduced baseline secretion (31 C, 77 ± 10 pg/10 min; 37 C, 114 ± 14 pg/10 min; P < 0.05). The data suggest that the inhibition of ACTH secretion during hypothermia is mediated by decreased hypothalamic secretion of AVP and OT which in turn decreases the pituitary responsiveness to CRF.
AB - To investigate the mechanism by which ACTH secretion is inhibited during hypothermia, hypophysial portal blood was collected from euthermic and hypothermic rats, and the concentrations of corticotropin-releasing factor (CRF), vasopressin (AVP), and oxytocin (OT) were measured by RIA. Whereas CRF levels in portal plasma were not different in the two groups, AVP and OT levels were significantly lower in hypothermic rats. The concentration of AVP and OT in peripheral plasma was also significantly lower in hypothermic rats compared with euthermic controls. The pituitary responsiveness to CRF during hypothermia was tested in vivo and in vitro. In pentobarbital-anesthetized male rats injected iv with 0.1 or 1.0 nmol CRF, the ACTH response was significantly smaller in hypothermic compared with euthermic animals. However, hemipituitaries superfused at 31 C released the same amount of ACTH in response to 1 nM CRF as hemipituitaries superfused at 37 C (31 C, 541 ± 90 pg; 37 C, 563 ± 29 pg) despite reduced baseline secretion (31 C, 77 ± 10 pg/10 min; 37 C, 114 ± 14 pg/10 min; P < 0.05). The data suggest that the inhibition of ACTH secretion during hypothermia is mediated by decreased hypothalamic secretion of AVP and OT which in turn decreases the pituitary responsiveness to CRF.
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U2 - 10.1210/endo-116-2-723
DO - 10.1210/endo-116-2-723
M3 - Article
C2 - 2981677
AN - SCOPUS:0021962428
SN - 0013-7227
VL - 116
SP - 723
EP - 727
JO - Endocrinology
JF - Endocrinology
IS - 2
ER -