| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
( John Collins Warren Laboratories, Collis P. Huntington Memorial Hospital of Harvard University, Massachusetts General Hospital, Boston, Massachusetts)
Weanling, young adult, and older rats were partially hepatectomized and given injections intravenously of thymidine-2-C14 at intervals up to 50 hours. They were killed exactly 2 hours after the injection, and the specific activity of the hepatic DNA was determined. The rate of DNA synthesis in weanlings followed a biphasic curve with peaks at approximately 20–22 hours and 33–35 hours after the operation. In adults a delayed, single, broad peak appeared, the maximum response lagging behind the weanlings by 3 hours in young adults (4 months old) and by 8–12 hours in older animals (12–15 months).
It is suggested that the biphasic curve in weanlings may be attributable to the closer synchrony among the responding cells plus the superimposition of a regenerative stimulus upon an already rapidly growing liver, so that repetitive divisions may occur earlier and in a larger fraction of the cellular population than in the older animals. As age advances, the delay in initiating DNA synthesis becomes increasingly longer and synchrony correspondingly poorer. The importance of accurate knowledge of the timing of the maximum response is particularly stressed, since this factor is probably responsible for a good deal of the confusion extant in the literature on hepatic regeneration.
* This is publication No. 1147 of the Cancer Commission of Harvard University.
An earlier report of these findings was presented at meetings of the Federation of American Societies for Experimental Biology (4).
This work was supported by grants E-50A and E-279 from the American Cancer Society Inc. and by grant CA-02146-01 from the National Cancer Institute, National Institutes of Health.
Present address: Boston University School of Medicine.
This article has been cited by other articles:
|
|
 |
|
  R. G. SMITH, Y. SUN, H. JIANG, R. ALBARRAN-ZECKLER, and N. TIMCHENKO Ghrelin Receptor (GHS-R1A) Agonists Show Potential as Interventive Agents during Aging Ann. N.Y. Acad. Sci., November 1, 2007; 1119(1): 147 - 164. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. Masumoto, C. Tateno, A. Tachibana, R. Utoh, Y. Morikawa, T. Shimada, H. Momisako, T. Itamoto, T. Asahara, and K. Yoshizato GH enhances proliferation of human hepatocytes grafted into immunodeficient mice with damaged liver J. Endocrinol., September 1, 2007; 194(3): 529 - 537. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. C. Sadler, K. N. Krahn, N. A. Gaur, and C. Ukomadu Liver growth in the embryo and during liver regeneration in zebrafish requires the cell cycle regulator, uhrf1 PNAS, January 30, 2007; 104(5): 1570 - 1575. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G.-L. Wang, X. Shi, E. Salisbury, Y. Sun, J. H. Albrecht, R. G. Smith, and N. A. Timchenko Growth Hormone Corrects Proliferation and Transcription of Phosphoenolpyruvate Carboxykinase in Livers of Old Mice via Elimination of CCAAT/Enhancer-binding Protein {alpha}-Brm Complex J. Biol. Chem., January 12, 2007; 282(2): 1468 - 1478. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Gelfant and J. G. Smith Jr. Aging: Noncycling Cells an Explanation: Cell and tissue aging is the result of transitions from cycling to noncycling cells Science, October 27, 1972; 178(4059): 357 - 361. [PDF]
|
|
|
|
|
|
B. Barbiroli and V. R. Potter DNA Synthesis and Interaction between Controlled Feeding Schedules and Partial Hepatectomy in Rats Science, May 14, 1971; 172(3984): 738 - 741. [Abstract] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Cancer Research | Clinical Cancer Research |
| Cancer Epidemiology Biomarkers & Prevention | Molecular Cancer Therapeutics |
| Molecular Cancer Research | Cancer Prevention Research |
| Cancer Prevention Journals Portal | Cancer Reviews Online |
| Annual Meeting Education Book | Meeting Abstracts Online |
