Serum S100B protein is increased in fasting rats.
BACKGROUND
S100B is a calcium-binding protein expressed and secreted by astrocytes; serum and cerebrospinal fluid (CSF) S100B elevation has been proposed as an index of brain damage. However, other tissues are shown to produce this protein and the clinical significance of serum S100B elevation has been discussed.


METHODS
We investigated the levels of serum and CSF S100B in fasting Wistar rats. Animals were divided into two groups, control and fasting for 48 h, and S100B levels in serum and CSF were determined by ELISA. S100B secretion in dissociated epididymal fat cells was investigated in the presence of epinephrine.


RESULTS
We observed a significant >2-fold increase of S100B levels in serum of fasting rats, without changes in its CSF content. Moreover, we demonstrated in vitro epinephrine stimulated S100B release from fat cells.


CONCLUSIONS
Present results reinforce that extracerebral sources of S100B, particularly adipocytes, contribute to its serum levels and support the idea that caution is needed when interpreting serum S100B increase as a clinical marker of brain damage.
Netto
Cristina B O
CB
Dept. Bioquímica, Instituto de Ciências Básicas da Saúde, UFRGS, Porto Alegre, Brazil.
Conte
Sabrina
S
Leite
Marina C
MC
Pires
Caroline
C
Martins
Tiago L
TL
Vidal
Penélope
P
Benfato
Mara S
MS
Giugliani
Roberto
R
Gonçalves
Carlos-Alberto
CA
D000818:Animals; D015415:Biomarkers / Q000097:blood / Q000134:cerebrospinal fluid; D001930:Brain Injuries / Q000097:blood; D002478:Cells, Cultured; D030501:Epididymal Secretory Proteins / Q000032:analysis*; D004822:Epididymis / Q000166:cytology / Q000378:metabolism; D004837:Epinephrine / Q000494:pharmacology; D005215:Fasting / Q000097:blood* / Q000134:cerebrospinal fluid*; D008297:Male; D009414:Nerve Growth Factors / Q000097:blood* / Q000134:cerebrospinal fluid*; D051381:Rats; D017208:Rats, Wistar; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins / Q000097:blood* / Q000134:cerebrospinal fluid*; D013997:Time Factors; D014662:Vasoconstrictor Agents / Q000494:pharmacology
D015415:Biomarkers; D030501:Epididymal Secretory Proteins; D009414:Nerve Growth Factors; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; C579158:S100b protein, rat; D014662:Vasoconstrictor Agents; D004837:Epinephrine