Age-related impairment of K(+)- and ACTH-stimulated aldosterone secretion by rat adrenal capsules.
It has been suggested that the decrease in plasma aldosterone concentration with advancing age is due to a direct effect of aging on adrenal cortical function. In this study, aldosterone secretion by adrenal capsules from male Fischer 344 rats that were 3-5, 11-13, and 19-21 mo of age was evaluated. Adrenal capsules, comprising the capsule, zona glomerulosa, and small portions of the zona fasciculata-reticularis, were perifused in vitro. Basal aldosterone secretion progressively decreased with aging. In response to concentrations of KCl that ranged from 5.0 to 9.0 mM and to adrenocorticotropic hormone (ACTH) that ranged from 10(-11) to 10(-8) M, threshold sensitivity of adrenal capsules to these secretagogues decreased with aging. Moreover, the magnitude of change in K(+)- and ACTH-stimulated aldosterone secretion and maximal aldosterone response of the adrenal capsules to KCl decreased with aging. Thus it is concluded that aging directly affects basal aldosterone secretion by rat adrenal capsules and that there is an age-related impairment of threshold sensitivity and responsiveness of adrenal capsules to the secretagogues, KCl and ACTH.
Radke
K J
KJ
School of Nursing, University of Rochester, New York 14642.
D000302:Adrenal Cortex / Q000378:metabolism*; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology*; D000375:Aging / Q000378:metabolism*; D000450:Aldosterone / Q000378:metabolism*; D000818:Animals; D046508:Culture Techniques; D008297:Male; D011188:Potassium / Q000494:pharmacology*; D051381:Rats; D011916:Rats, Inbred F344
D000450:Aldosterone; D000324:Adrenocorticotropic Hormone; D011188:Potassium