More long-term CR testosterone

[Guest guest]

Hi All,

Here is a paper that is not pdf-available and may suggest that the reduced

testosterone level initially seen in CRers is relatively higher in later ages.

Chen H, Luo L, Liu J, Brown T, Zirkin BR.

Aging and caloric restriction: Effects on Leydig cell steroidogenesis.

Exp Gerontol. 2005 May 31; [Epub ahead of print]

PMID: 15935587

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve & db=pubmed & dopt=Abstra\

ct & list_uids=15935587 & query_hl=1

.... CR (40%) was initiated in 4 month-old Brown Norway rats, and continued

through

age 34 months. Serum testosterone concentration in the ad libitum (AL)-fed

controls

was reduced by 30% from 5 to 13 months, by another 67% through 25 months, and

then

was sustained through 34 months. For the CR rats, the serum testosterone level

was

reduced to 45% of AL controls by 5 months, only 6 weeks after the initiation of

the

CR regimen. There was no further reduction through 25 months, at which time

serum

testosterone concentration in CR animals was significantly higher than in AL

controls. By age 28-34 months, there was no significant difference between the

two

diets. The weights of prostate and seminal vesicle, two biomarkers of serum

androgen

levels, were consistent with the changes in serum testosterone concentration in

both

AL and CR animals. The ability of isolated Leydig cells to produce testosterone

in

vitro also paralleled the age- and CR-related changes in serum testosterone

concentration. CR resulted in a rapid, 36% reduction in testosterone production

from

control by age 5 months. In contrast to cells from the AL rats, there were no

further decreases in testosterone production through age 25 months. Indeed,

Leydig

cells from the 25 month-old CR rats produced significantly greater amounts of

testosterone than cells from the 25 month-old AL rats. These results indicate

that

short-term CR results in the suppression of Leydig cell function and in

reduction in

serum testosterone levels. The significantly higher concentrations of serum

testosterone concentration, and increased Leydig cell testosterone production,

elicited by CR in 25 month-old rats compared to AL controls suggest that

long-term

CR can transiently suppress the reductions in steroidogenesis that are

characteristic of aging.

Al Pater, PhD; email: old542000@...

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