Age-dependent reversal of the lobular distribution of androgen-inducible alpha 2u globulin and androgen-repressible SMP-2 in rat liver.
Hepatocytes situated at pericentral and periportal zones of the liver lobule show differences in the expression of several liver-specific genes, such as androgen-inducible alpha 2u globulin and androgen-repressible senescence marker protein-2 (SMP-2). A marked temporal difference in the expression of these two androgen-regulated genes has also been observed. The liver of the pre-pubertal male rat is insensitive to androgen, and during this period hepatocytes synthesize only SMP-2. During young adult life (greater than 40 days), the liver becomes androgen sensitive and concomitant synthesis of alpha 2u globulin and repression of SMP-2 occur. In the senescent male rat (greater than 750 days), the liver again becomes androgen insensitive when the decline in alpha 2u globulin is accompanied by an increase in SMP-2 synthesis. In this article we present results to show a correlation between the temporal and spatial (intralobular) changes in the expression of the androgen-inducible alpha 2u globulin and the androgen-repressible SMP-2 in rat hepatocytes. Results indicate that the temporal changes in hepatic androgen sensitivity are dictated by the intralobular location of the hepatocytes. Hepatocytes located around the central vein (pericentral/perivenous) may benefit from a paracrine advantage for the expression of a subset of genes, including the gene for the androgen receptor.
Mancini
M A
MA
Department of Cellular and Structural Biology, University of Texas Health Sciences Centre, San Antonio 78284.
Chatterjee
B
B
Roy
A K
AK
D000375:Aging / Q000378:metabolism*; D000510:Alpha-Globulins / Q000032:analysis / Q000378:metabolism*; D000728:Androgens / Q000494:pharmacology*; D000818:Animals; D015153:Blotting, Western; D002135:Calcium-Binding Proteins; D005260:Female; D007150:Immunohistochemistry / Q000379:methods; D008099:Liver / Q000737:chemistry / Q000166:cytology / Q000378:metabolism*; D008297:Male; D011506:Proteins / Q000032:analysis / Q000378:metabolism*; D051381:Rats; D011916:Rats, Inbred F344; D015238:Sulfotransferases
D000510:Alpha-Globulins; D000728:Androgens; D002135:Calcium-Binding Proteins; D011506:Proteins; C013803:alpha 2u globulin; D015238:Sulfotransferases; C028152:alcohol sulfotransferase