Dehydration of prostaglandins: study by spectroscopic method.

The ultraviolet (UV) and optical rotatory dispersion (ORD) spectra of prostaglandins E(1), A(1), B(1), and their naturally derived 15-epimers are presented. The dehydration sequence E --> A --> B under acidic and basic conditions has been studied by UV and ORD. Conditions for quantitative conversion of PGE(1) to PGA(1) are described. The combination of ORD and UV affords a nondestructive assay which can determine the relative amounts of E-, A-, and B-type prostaglandins with as little as 1-2 micro g of material. The total quantity of prostaglandins can be estimated (+/-15%) in this way or, more accurately, by treatment with alkali of an aliquot (200 ng is sufficient) and determination of the change in absorbance at 278 nm.