In mammalian cells, there are three kinds of polyamine:

1. 多氨素及鳥氨酸脫羧脢對未著床小鼠胚胎生長的影響Effects of Polyamines and Ornithine Decarboxylase on the Growth of Preimplanted Mouse Embryo • 在哺乳動物細胞中含有三種多氨素: putrescine, spermidine, 及spermine。在合成多氨素的過程中，Ornithine decarboxylase (ODC)為起始及決定反應速度的酵素。 a-Difluoro-methylornithine (DFMO)為ODC之不可逆性專一抑制劑。許多文獻已證實多氨素對細胞之生長及分化扮演一重要角色，而早期未著床胚胎具快速分裂細胞群，因而多氨素也許也在早期胚胎發育中佔一要席。目前多氨素對哺乳動物胚胎中生長之影響及ODC基因表現仍未被清楚地探討，所以我們觀察了多氨素對胚胎生長的可能影響及在不同階段胚胎ODC-mRNA 及ODC 蛋白質量的變化。將2-cellstage 的胚胎分別在HTF 培養液或含putrescine, spermidine,spermine, MGBG, DFMO 或含DFMO加putrescine的HTF培養液培養來觀察多氨素對胚胎的影響， 結果顯示加入多氨素合成酵素之抑制劑對胚胎生長並無抑制的現象。ODC 蛋白質在2-cell stage 就可利用免疫染色法測得，顯示雖然ODC在胚胎早期就已表現了，但是DFMO卻不能抑制胚胎生長，可能因為胚胎內已含有大量的putrescine及其他多氨素，足夠維持到胚胎的發育至blastocyst而不受抑制劑的影響。另一方面，以RT-PCR的方法來探測著床前胚胎內ODC mRNA 的量，以目前的one step PCR 方法，只能明顯偵測到blastocyst 期胚胎內ODC-mRNA 的存在。在討論中，將述及目前技術上尚未能測得較早期胚胎內ODC-mRNA 量的原因及可能解決的方法。同時也討論為何在4-cell stage以上到孵化的blastocyst 均未能順利以細胞免疫染色法來觀察的可能原因與解決方法。

2. In mammalian cells, there are three kinds of polyamine: • putrescine, spermidine and spermine. Their first and rate • limiting enzyme is ornithine decarboxylase (ODC). a-Difluoro- • methylornithine (DFMO) is an irreversible and specific inhibitor • of ODC. Data from numerous references show that polyamines are • essential for cell growth, proliferation and differentiation. • Because early preimplanted embryos containing fast dividing • cells, polyamines may also play a role in the development of • these early embryos. The functional role of polyamines and the • expression of ODC gene during the development of early mammalian • embryos are not well understood, we have attempted to study the • expression of ODC-mRNA as well as protein, aoliferation study • the effect of polyamines on the embryo at different stages of • embryo development. Groups of cultured 2-cell stage mouse • embryos were exposed to various concentrations of putrescine, • spermidine, spermine, DFMO, or DFMO plus putrescine. DFMO • appeared not to affect the growth of embryos. On the other hand, • ODC protein was detected in the 2-cell stage embryo as revealed • by immunocytochemical study. This shows that ODC was expressed • during early embryo development prior to implantation although • DFMO failed to suppress embryo development. It is thus • speculated that there is abundant putrescine to suppport early • embryo development without de novo synthesis. However, the • immuno-cytochemical study on the embryos after 4-cell stage • suffered technical difficulties. On the other hand, we have also • intend to compare ODC mRNA by RT-PCR in various stages of the • preimplanted embryo. The currently used one step PCR method can • only detect blastocyst and morula stage ODC mRNA. The difference • in hatched and hatch-arrested embryos were compared. The • technical difficulties and possible resolutions for the • immunocytochemical studies from 2-cell to blastocyst stage • embryos and the quantitation of ODC-mRNA before blastocyst stage • embryos will be discussed.