Aging effects on the secretion of corticosterone in male rats.
BACKGROUND
The effects of aging on zona fasciculatareticularis (ZFR) cell function in male rats were studied.


METHODS
Male rats 3, 6, and 22 months of age were divided into three groups, and collagenase-dispersed ZFR cells were isolated and incubated with adrenocorticotropin (ACTH), 8-bromo-adenosine 3':5'-cyclic monophosphate (8-Br-cAMP), ovine prolactin (oPRL), deoxycorticosterone (DOC), or 3-isobutyl-l-methylxanthine (IBMX) at 37 degrees C for 1 hour. Corticosterone concentrations in cell media and cAMP production in ZFR cells were measured by radioimmunoassay. Protein expression of PRL receptor in ZFR cells were analyzed by Western blot.


RESULTS
The basal levels of plasma and medium corticosterone were higher in 22-month-old than in 3-month-old rats. In contrast, the release of corticosterone in response to ACTH, 8-Br-cAMP, and DOC was lower in 22-month-old than in 3- and 6-month-old rats. Aging decreased the oPRL-stimulated release of corticosterone but increased the protein expression of PRL receptor in ZFR cells. The basal levels of intracellular cAMP increased with age. However, the ACTH-stimulated production of intracellular cAMP decreased in 22-month-old compared with 3- or 6-month-old rats. The increment of cAMP accumulation in ZFR cells after administration of IBMX was greater in 22-month-old than in 3- or 6-month-old rats.


CONCLUSIONS
These results suggest that the aging effects on the production of corticosterone in rat ZFR cells is associated with change of the generation of cAMP, the activity of 11 beta-hydroxylase and the protein expression of PRL receptor.
Lo
M J
MJ
Department of Physiology, School of Life Science, National Yang-Ming University, Taipei, Taiwan, Republic of China.
Kau
M M
MM
Cho
W L
WL
Wang
P S
PS
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology; D000375:Aging / Q000502:physiology*; D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D003345:Corticosterone / Q000032:analysis / Q000097:blood*; D017077:Culture Media, Conditioned / Q000737:chemistry; D000242:Cyclic AMP / Q000032:analysis / Q000378:metabolism; D003900:Desoxycorticosterone / Q000494:pharmacology; D008297:Male; D011388:Prolactin / Q000097:blood / Q000494:pharmacology; D011863:Radioimmunoassay; D051381:Rats; D017207:Rats, Sprague-Dawley; D011981:Receptors, Prolactin / Q000032:analysis / Q000378:metabolism; D015383:Zona Fasciculata / Q000187:drug effects / Q000502:physiology*; D015385:Zona Reticularis / Q000187:drug effects / Q000502:physiology*
D017077:Culture Media, Conditioned; D011981:Receptors, Prolactin; D015124:8-Bromo Cyclic Adenosine Monophosphate; D003900:Desoxycorticosterone; D000324:Adrenocorticotropic Hormone; D011388:Prolactin; D000242:Cyclic AMP; D015056:1-Methyl-3-isobutylxanthine; D003345:Corticosterone