Distinct effects of testosterone on plasma and cerebrospinal fluid amyloid-beta levels.
The effect of testosterone on the levels of the Alzheimer's disease amyloid-beta peptide (Abeta) was investigated in guinea pigs. Castrated guinea pigs (GPX) were administered testosterone at two different dosages, following which plasma and cerebrospinal fluid (CSF) Abeta_{40} levels were measured. Plasma Abeta_{40} levels were reduced in GPX in the early stages of low-dose testosterone treatment, whereas CSF Abeta_{40} levels were only reduced by the time circulating testosterone had returned to untreated GPX levels. The supraphysiological testosterone dose did not reduce CSF Abeta_{40} levels significantly until circulating testosterone was back to uncastrated levels, whereas plasma Abeta_{40} levels significantly increased over time in these animals. These results indicate that the extent of testosterone-induced changes to Abeta_{40} levels and their response rates depend on both the tissue examined and testosterone dosage.
Wahjoepramono
Eka J
EJ
Centre of Excellence for Alzheimer's Disease Research and Care, School of Exercise, Biomedical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia.
Wijaya
Linda K
LK
Taddei
Kevin
K
Martins
Georgia
G
Howard
Matthew
M
de Ruyck
Karl
K
Bates
Kristyn
K
Dhaliwal
Satvinder S
SS
Verdile
Giuseppe
G
Carruthers
Malcolm
M
Martins
Ralph N
RN
D000544:Alzheimer Disease / Q000097:blood* / Q000134:cerebrospinal fluid*; D016564:Amyloid beta-Protein Precursor / Q000097:blood / Q000134:cerebrospinal fluid / Q000187:drug effects; D000818:Animals; D002369:Castration; D006168:Guinea Pigs; D008297:Male; D013739:Testosterone / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D013997:Time Factors
D016564:Amyloid beta-Protein Precursor; D013739:Testosterone