Vol. 281, Issue 1, E138-E146, July 2001
Differential regulation of IGFBP-2 and IGFBP-5 gene expression
by vitamin A status in Japanese quail
Zhengwei
Fu,
Tadashi
Noguchi, and
Hisanori
Kato
Laboratory of Nutritional Biochemistry, Department of Applied
Biological Chemistry, Graduate School of Agricultural and Life
Sciences, University of Tokyo, Tokyo 113 - 8657, Japan
To investigate the
involvement of the insulin-like growth factor (IGF) system in vitamin A
(VA)-supported growth, we examined the effects of VA status on IGF
binding protein (IGFBP)-2 and -5 gene expression in Japanese quail. VA
deficiency caused a reduction in IGFBP-2 mRNA only in lung, without
effect in other tissues. However, the expression of IGFBP-5 mRNA was
more sensitive to the change of VA status. IGFBP-5 mRNA levels were
significantly reduced by VA depletion in a tissue-specific manner,
which preceded the decrease in body weight. A single injection of
retinoic acid or retinol to VA-deficient quail did not affect the
levels of IGFBP-2 mRNA, but it rapidly induced the expression of
IGFBP-5 mRNAs in some tissues. These results are the first to show that gene expression of some IGFBPs in vivo are under the control of VA
status and suggest a possible involvement of the IGF system in
mediating the physiological actions of VA in the growth of Japanese quail.
insulin-like growth factor binding proteins-2 and -5; vitamin A
deficiency; vitamin A repletion
