Distribution of albumin, alpha 1-inhibitor 3 and their respective mRNAs in periportal and perivenous rat hepatocytes isolated by the digitonin-collagenase technique.
The expression of albumin and alpha 1-inhibitor 3 genes was investigated in rat cell suspensions enriched in periportal (n = 10) and perivenous (n = 10) hepatocytes obtained by the digitonin-collagenase technique. The degree of enrichment of the cell suspensions was assessed: (1) by enzymic assays for the periportal marker alanine aminotransferase and for the perivenous marker glutamine synthetase; and (2) by their content of mRNAs for the periportal marker hepatic glutaminase and for glutamine synthetase. The existence of an antegrade intra-lobular gradient for albumin and alpha 1-inhibitor 3 mRNAs was demonstrated, with periportal:perivenous ratios of 2.33 and 3.80, respectively. However, no gradient was demonstrated for the respective protein contents with corresponding ratios of 0.98 and 1.21. A certain degree of overlap existed between periportal and perivenous suspensions for their content in albumin and alpha 1-inhibitor 3 mRNAs. A morphometrical analysis of the surface of digitonin-permeabilized hepatic tissue revealed that this overlap could be explained by a variable extent of permeabilization of the mediolobular zone from one rat to another and from one lobule to another in a given animal. These results suggest that while the digitonin-collagenase technique is well suited for studies in vitro of proteins expressed in sharp intra-lobular gradients or restricted to an intra-lobular compartment, it is not completely reliable for proteins distributed in continuous moderate intra-lobular gradients, such as albumin and alpha 1-inhibitor 3.
Racine
L
L
Laboratoire de Biologie Cellulaire, Unité INSERM 327, Faculté de Médecine Xavier Bichat, Paris, France.
Scoazec
J Y
JY
Moreau
A
A
Chassagne
P
P
Bernuau
D
D
Feldmann
G
G
D000209:Acute-Phase Proteins; D000818:Animals; D017364:Collagenases; D004072:Digitonin; D005069:Evaluation Studies as Topic; D015870:Gene Expression; D007206:Individuality; D008099:Liver / Q000098:blood supply / Q000737:chemistry* / Q000166:cytology; D008297:Male; D010477:Perfusion; D011480:Protease Inhibitors / Q000032:analysis* / Q000737:chemistry* / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis* / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D012709:Serum Albumin / Q000032:analysis* / Q000096:biosynthesis / Q000235:genetics*
D000209:Acute-Phase Proteins; D011480:Protease Inhibitors; D012333:RNA, Messenger; D012709:Serum Albumin; C017894:alpha 1-inhibitor 3; D017364:Collagenases; D004072:Digitonin