Sex- and age-related changes in catecholamine metabolism and release of rat adrenal gland.
To examine the possible existence of changes in the adrenal catecholaminergic activity during aging, we analyzed the adrenal content of catecholamines (CA) and the activities of selected enzymes involved in their metabolism as well as the basal and the K+-stimulated release of these CA in incubated adrenal tissue of aged (greater than 22 months) and young (2 months) rats of both sexes. Adrenal contents of norepinephrine (NE) and epinephrine (E) of male rats were unaltered in aging, although aged males showed an increased activity of tyrosine hydroxylase (TH) and a decrease in phenylethanolamine-N-methyl transferase (PNMT) activity. In addition, the in vitro release of both CA as well as their content in the incubated adrenal tissue were higher in aged males than in young animals. However, the response of the adrenal of aged males to incubation with stimulatory concentrations of K+ was significantly lower than that observed in young males. Aged females showed increases in the adrenal content of E, although the activities of TH and PNMT were unaltered. As in aged males, the in vitro release of CA from incubated adrenal tissue was higher in aged females than in young rats, but the CA amounts measured in the incubated tissues were similar. Moreover, the response to stimulatory concentrations of K+ was lower in aged females than in young animals. In summary, these results clearly indicate that adrenal catecholaminergic activity is enhanced during aging, which could have important consequences for physiological functions regulated by the adrenal secretion. Also, some differences in the effects of aging could be observed between males and females.
Fernandez-Ruiz
J J
JJ
Department of Biochemistry, Faculty of Medicine, Complutense University, Madrid, Spain.
Bukhari
A R
AR
Hernandez
M L
ML
Alemany
J
J
Ramos
J A
JA
D000311:Adrenal Glands / Q000378:metabolism*; D000367:Age Factors; D000375:Aging / Q000502:physiology*; D000818:Animals; D002395:Catecholamines / Q000378:metabolism*; D005260:Female; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012737:Sex Factors
D002395:Catecholamines