|
|
|
|||
| Home Help Feedback Subscriptions Archive Search Table of Contents | ||||
Development, Vol 114, Issue 1 185-192, Copyright © 1992 by Company of Biologists
JOURNAL ARTICLES |
M Alexiou and HJ Leese
Department of Biology, University of York, Heslington, UK.
The importance of de novo purine synthesis as opposed to the reutilisation of metabolites by salvage pathways, and the nature of the excretory product(s) of purine degradation, have been examined in cultured preimplantation mouse embryos. In the presence of azaserine and mycophenolic acid, which inhibit de novo purine synthesis, embryo cleavage was blocked prior to compaction, the precise stages at which this occurred depended on whether the cultures were established on day 1 or day 2 after fertilisation, and indicated that salvage pathways were insufficient to fulfil the demand for nucleotides during early preimplantation development. The end-product of purine degradation appeared to be xanthine, which was excreted in very small amounts on days 1, 2 and 3, with a pronounced rise from the early to late blastocyst. Uric acid formation or excretion could not be detected. Exogenous hypoxanthine and adenine, which partially inhibited development, were taken up by the embryos and converted to xanthine, most probably by salvage pathways, since the enzyme xanthine oxidase, which converts hypoxanthine directly to xanthine and then to uric acid, could not be detected. Exogenous guanine had little effect on development and was also converted to xanthine, but in this case, the conversion was probably in a single step, via the enzyme guanase.
This article has been cited by other articles:
![]() |
N. M Orsi and H. J Leese Ammonium exposure and pyruvate affect the amino acid metabolism of bovine blastocysts in vitro Reproduction, January 1, 2004; 127(1): 131 - 140. [Abstract] [Full Text] [PDF] |
||||
![]() |
F. D. Houghton1, J. A. Hawkhead, P. G. Humpherson, J. E. Hogg, A. H. Balen, A. J. Rutherford, and H. J. Leese Non-invasive amino acid turnover predicts human embryo developmental capacity Hum. Reprod., April 1, 2002; 17(4): 999 - 1005. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. Yamaoka, M. Kondo, S. Honda, H. Iwahana, M. Moritani, S. Ii, K. Yoshimoto, and M. Itakura Amidophosphoribosyltransferase Limits the Rate of Cell Growth-linked de Novo Purine Biosynthesis in the Presence of Constant Capacity of Salvage Purine Biosynthesis J. Biol. Chem., July 11, 1997; 272(28): 17719 - 17725. [Abstract] [Full Text] [PDF] |
||||