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Early pregnancy factor in liver regeneration after partial hepatectomy in rats: Relationship with chaperonin 10
Author(s) -
Quinn Kathryn A.,
Cavanagh Alice C.,
Hillyard Narelle C.,
McKay Dorothy A.,
Morton Halle
Publication year - 1994
Publication title -
hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.488
H-Index - 361
eISSN - 1527-3350
pISSN - 0270-9139
DOI - 10.1002/hep.1840200529
Subject(s) - chaperonin , pregnancy , medicine , biology , endocrinology , autocrine signalling , liver regeneration , fetus , andrology , microbiology and biotechnology , biochemistry , regeneration (biology) , receptor , genetics , protein folding
Abstract Early pregnancy factor is not only a product of dividing embryonic and neoplastic cells, as demonstrated previously, but also of normal proliferating cells. Eight hours after partial hepatectomy in rats, early pregnancy factor was detected in serum. It rose to a peak by 48 hr. Neutralization of early pregnancy factor in vivo by passive immunization with specific antibodies, 18 hr after partial hepatectomy, resulted in a significant decrease in the uptake of [H]thymidine by the liver remnant, measured 4 to 6 hr later. These results suggest that during liver regeneration, early pregnancy factor is essential to the sequence of events that culminates in DNA synthesis and cell division. Recently we purified early pregnancy factor from human platelets and determined by mass spectrometry a precise molecular mass of 10,843 Da. Amino acid sequencing (˜72% of the molecule) demonstrated that early pregnancy factor is highly homologous with chaperonin 10, a stress‐inducible mitochondrial protein, and that platelet‐derived early pregnancy factor and rat chaperonin 10 share similar biochemical and immunological properties. In this study we show that early pregnancy factor, purified from regenerating rat liver and from serum taken 24 hr after hepatectomy, shares these properties. In addition, antibodies to early pregnancy factor, effective in passive immunization studies, recognize chaperonin 10, whereas chaperonin 10 antibodies bind to early pregnancy factor from regenerating liver and posthepatectomy serum. We propose that early pregnancy factor/chaperonin 10 is selectively released from proliferating cells and, in an autocrine or paracrine mode (or both) is involved in DNA synthesis. (Hepatology 1994;20:1294–1302).