Effects of aging on cytochrome b5 expression in the human adrenal gland.
BACKGROUND
Aging in humans is characterized by a selective decline in circulating levels of adrenal androgens. The results of in vivo studies are suggestive of reduced adrenal 17,20-lyase activity in aging men and women.


OBJECTIVE
We sought to determine whether there are changes in the distribution and/or expression of cytochrome B5 (CytB5), an accessory protein important in the regulation of 17,20-lyase activity, in the adrenals of aging humans.


METHODS
Comparison between younger and older adrenal glands.


METHODS
The study was conducted in a University Center.


METHODS
Adrenal glands obtained at autopsy after sudden death as a result of trauma from 46 young (age 20-40 yr) and 26 older (age 50-91 yr) humans were obtained and fixed within 24 h postmortem.


METHODS
Paraffin sections were stained with hematoxylin and eosin and also were subjected to immunohistochemical staining for CytB5. All sections were quantitatively evaluated using an image capture and analysis program and qualitatively evaluated with respect to staining intensity.


METHODS
To determine whether there are any changes in CytB5 distribution in the adult human adrenal cortex during the aging process using qualitative and quantitative analysis with respect to age, gender, race, and postmortem interval.


RESULTS
CytB5 immunoreactivity was found in cells that corresponded to those of the zona reticularis. The percentage of the adrenal cortex immunoreactive for CytB5 decreased with aging (38.6 +/- 7.6% for young and 30.1 +/- 5.9% for older, mean +/- sd; P < 0.0001) as did the percentage of adrenocortical tissue comprising the zona reticularis (36.8 +/- 10.8% for young and 27.2 +/- 5.9% for older; P < 0.001). However, there was no apparent change in the staining intensity of CytB5 among those cells that were immunopositive for this factor with aging.


CONCLUSIONS
There appears to be a reduction in the proportion of the adrenal cortex that expresses CytB5 with aging, and this likely corresponds to a shrinkage of the zona reticularis. The mechanism and cause for this cortical regression are unknown.
Dharia
Sejal
S
Department of Obstetrics and Gynecology, University of Alabama at Birmingham, 618 South 20th Street, 360 Old Hillman Building, Birmingham, Alabama 35294-7333, USA.
Slane
Audry
A
Jian
Ming
M
Conner
Michael
M
Conley
Alan J
AJ
Brissie
Robert M
RM
Parker
C Richard
CR
D000311:Adrenal Glands / Q000201:enzymology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism*; D015786:Cytochromes b5 / Q000032:analysis*; D019314:Dehydroepiandrosterone Sulfate / Q000378:metabolism; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged
D019314:Dehydroepiandrosterone Sulfate; D015786:Cytochromes b5