P 67

NALOXONE INHIBITS DEVELOPMENT OF PREIMPLANATATION MOUSE EMBRYOS

73

A.E.KALYUZHNY, O.V.MIRONOVA,E.S.PLATONOV, G.T.SUKHIKH, All-Union Research

Center for Maternal & Child Health Care, Oparin Str. 4, 117815,Moscow, USSR

Recent reports have provide evidence that opioid pepetide ~-endorphin (B-E) is

localized in the area surrounding oocyte and developing embryo in vivo. Thus the

possibility exists that B-E may stimulate embryo growth.We evaluated that opiate

antagonist naloxone (NAL) in concentration 3x10-5M markedly suppressed the pro-

portion of embryos which reached late morula and blastula stages.Suppression was

stage specific with maximal effect after NAL addition to zygotes.No more than

30 min of incubation zygotes with NAL was necessary to recieve the suppression.

When NAL action was partially antagonized by B-E analog, synthetic pepetide DAGO

- percentage of embryos reaching blastocyst stage was 66,8% rather than 7,36

when NAL was added alone.The present data indicate specificity of NAL action and

suggest that B-E may play a role of growth factor, whose action may "protect"

developing embryo from lympho- and monokines of activated leucocytes, which,

like NAL, inhibit embryo development.

opioids, suppression, pre-embryos

P 68

PROPERTIES OF EMBRYO-DERIVED PLATELET ACTIVATING FACTOR

1 2 1 I~.T. Podsiadly, JI_.M. Adamson, R.A. Stirllng, Y.C.2Smart , J. Stanger, & 'T.K. Roberts r I Department of Biological Sciences & Faculty of Medicine,

University of Newcastle, NSW 2308

Mouse embryos release a phospholipld molecule (EPAF) similar to platelet activating factor (PAF). EPAF is an important embryonic signal in the establishment of pregnancy part icularly in the phase of implantation. In molecular terms PAF consists of a family of molecules. These molecules have potent biological properties, are synthesised by many cell types and can be readily inactivated by acetyl hydrolases. PAFs are characterised by the abi l i ty to induce platelet aggregation and activation. EPAF on the other hand, although earlier reported to be PAF-l ike appears to have some different properties in v i t ro and in viva. In viva EPAF was shown to be more closely related to C. .PAF. However, in dose response studies EPAF appeared to be

I¢~ . modulated in its act iv i ty. Enzymic inactivation studies showed that the platelet activating factor-l ike act iv i ty of embryos was resistant to hydrolysis whereas PAF was readily inactivated. However, when the EPAF was extracted from embryo culture medium using chloroform/methanol, the in viva act iv i ty was readily lost on treatment with plasma. In vi tro studies showed that EPAF in culture medium was not able to induce aggregation similar to that induced by PAF, however, upon separation of EPAF by thin layer chromatography an active fraction was obtained. These studies indicate that the mouse embryo releases the potent pharmacological agent PAF complexed to a protective carrier molecule which modulates its biological act iv i ty.

Embryo; PAF; implantation; growth factors.