WHICH PROSTANOID METABOLITES SHOULD BE DETERMINED FOR THE STUDY OF REPRODUCTIVE PROCESSES

The non-enzymatic metabolites of prostacyclin (PGI(2)) and thromboxane A(2) (TXA(2)), 6-keto-prostaglandin F-1 alpha (6-keto-PGF(1 alpha)) a nd thromboxane B-2 (TXB2), and their 2,3-dinor metabolites, 2,3-dinor- 6-keto-PGF(1 alpha) and 2,3-dinor TXB2, were measured in early morning urine samples in 24 in vitro fertilization (IVF) cycles in 24 women a nd in 27 women who became pregnant after IVF and embryo transfer (ET). The sum of the non-enzymatic metabolites and their 2,3-dinor metaboli tes was considered to be a reflection of total PGI(2) and total TXA(2) production in vivo. Both the ratio of 'total' PGI(2)/'total' TXA(2) a nd the ratio of the 2,3-dinor metabolites were calculated. TXB2 concen trations showed virtually no change and the ratios of the non-enzymati c metabolites of PGI(2) and TXA(2) versus their 2,3-dinor metabolites remained relatively constant. As a consequence, the ratio of 2,3-dinor -6-keto-PGF(1 alpha)/2,3-dinor-TXB2 was a close reflection of the rati o of 'total' PGI(2)/'total' TXA(2), although the latter ratio was sign ificantly higher all the time. We conclude that for comparative studie s on the balance between PGI(2) and TXA(2) in IVF cycles and during ge station, the determination of the 2,3-dinor metabolites alone can repl ace the measurement of all four metabolites.