TY - JOUR
T1 - Tyrosine hydroxylase expression in rat adrenal medulla
T2 - Influence of age and cold
AU - Tümer, Nihal
AU - Larochelle, Jeffrey S.
N1 - Funding Information:
This work was supportedb y grantsf rom the Merit ReviewP ro-gramo f the Departmenotf VeteransA ffairs MedicalR esearchS ervice and from the American Heart Association, Florida Affiliate. We thankD r. Karen G’Malley of WashingtonU niversityS choolo f Medicine, St. Louis, MO, for providingt he TH.36 cDNA probe. We also thankJ anice Dolson and Anne Crawford for manuscrippt reparation and Janet Woottenf or editingt hem anuscript.
PY - 1995/8
Y1 - 1995/8
N2 - Chronic and cold exposure is associated with an increase in adrenal medullary tyrosine hydroxylase (TH) activity and expression that may be important for the regulatory response to cold. Senescent rats do not maintain their body temperature as well as young rats. We investigated the ability of the catecholaminergic system of older rats to respond to cold stimulus. TH activity, TH immunoreactivity, and TH mRNA were assessed in adrenal medullae of male F-344 rats of 3 and 24 months of age following 48 h of mild (8 °C) cold exposure. In control rats, basal levels of TH activity were increased by 2.9-fold, TH immunoreactivity by 1.3-fold, and TH mRNA by 2.3-fold with age. In the young rats there were increases after a 48-h cold exposure in TH activity, TH immunoreactivity, and TH mRNA per pair of adrenal medullae. In contrast, in senescent rats there were no significant changes in these parameters following cold exposure. These data suggest that the induction of TH activity is impaired in senescent rats following cold exposure and that there is a loss of plasticity with respect to the TH gene expression.
AB - Chronic and cold exposure is associated with an increase in adrenal medullary tyrosine hydroxylase (TH) activity and expression that may be important for the regulatory response to cold. Senescent rats do not maintain their body temperature as well as young rats. We investigated the ability of the catecholaminergic system of older rats to respond to cold stimulus. TH activity, TH immunoreactivity, and TH mRNA were assessed in adrenal medullae of male F-344 rats of 3 and 24 months of age following 48 h of mild (8 °C) cold exposure. In control rats, basal levels of TH activity were increased by 2.9-fold, TH immunoreactivity by 1.3-fold, and TH mRNA by 2.3-fold with age. In the young rats there were increases after a 48-h cold exposure in TH activity, TH immunoreactivity, and TH mRNA per pair of adrenal medullae. In contrast, in senescent rats there were no significant changes in these parameters following cold exposure. These data suggest that the induction of TH activity is impaired in senescent rats following cold exposure and that there is a loss of plasticity with respect to the TH gene expression.
KW - Cold exposure
KW - F-344 rats
KW - Tyrosine hydroxylase
UR - http://www.scopus.com/inward/record.url?scp=0029001462&partnerID=8YFLogxK
U2 - 10.1016/0091-3057(95)00030-Z
DO - 10.1016/0091-3057(95)00030-Z
M3 - Article
C2 - 7675858
AN - SCOPUS:0029001462
SN - 0091-3057
VL - 51
SP - 775
EP - 780
JO - Pharmacology, Biochemistry and Behavior
JF - Pharmacology, Biochemistry and Behavior
IS - 4
ER -