TY - JOUR
T1 - Influence of age and gender on brown adipose tissue norepinephrine turnover
AU - McDonald, R. B.
AU - Hamilton, J. S.
AU - Horwitz, Barbara A
PY - 1993
Y1 - 1993
N2 - We hypothesized that the attenuated brown adipose tissue thermogenic capacity observed previously in cold-exposed 27-month-old male versus female Fischer 344 rats might result, in part, from blunted sympathetic signaling to the tissue. As an index of sympathetic activity to brown fat, norepinephrine (NE) turnover in this tissue was evaluated at rest (22-24°C) and during 1.5 hr of cold exposure (6°C) in male and female Fischer 344 rats, aged 6, 12, and 26 months. Resting NE turnover as well as the rate constant for NE efflux from brown fat, expressed as total and as per gram of tissue protein, did not, in general, differ from age or gender. During cold exposure, rate constants and NE turnover rates increased significantly from those at rest in all groups. Brown fat NE turnover in cold-exposed 26-month-old male rats was greater than that observed in age-matched females, suggesting greater, not less, sympathetic signaling in the males versus females. These data indicate that the attenuated brown fat thermogenic capacity as well as the blunted cold-induced thermogenic responses of cold-exposed older male versus female rats reported previously cannot be explained by diminished release of NE from sympathetic nerves innervating brown adipose tissue.
AB - We hypothesized that the attenuated brown adipose tissue thermogenic capacity observed previously in cold-exposed 27-month-old male versus female Fischer 344 rats might result, in part, from blunted sympathetic signaling to the tissue. As an index of sympathetic activity to brown fat, norepinephrine (NE) turnover in this tissue was evaluated at rest (22-24°C) and during 1.5 hr of cold exposure (6°C) in male and female Fischer 344 rats, aged 6, 12, and 26 months. Resting NE turnover as well as the rate constant for NE efflux from brown fat, expressed as total and as per gram of tissue protein, did not, in general, differ from age or gender. During cold exposure, rate constants and NE turnover rates increased significantly from those at rest in all groups. Brown fat NE turnover in cold-exposed 26-month-old male rats was greater than that observed in age-matched females, suggesting greater, not less, sympathetic signaling in the males versus females. These data indicate that the attenuated brown fat thermogenic capacity as well as the blunted cold-induced thermogenic responses of cold-exposed older male versus female rats reported previously cannot be explained by diminished release of NE from sympathetic nerves innervating brown adipose tissue.
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M3 - Article
C2 - 8372094
AN - SCOPUS:0027200604
VL - 204
SP - 117
EP - 121
JO - Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N. Y.)
JF - Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N. Y.)
SN - 1535-3702
IS - 1
ER -