1. The effects of prostaglandin (PG) E1, PGE2 and PGF2α on plasma renin substrate concentration in rats and renin substrate production by perfused rat liver were investigated.
2. After bilateral nephrectomy, both plasma renin substrate concentration and renin substrate production were remarkably elevated.
3. The increase in plasma renin substrate level and production of renin substrate by the liver after nephrectomy was markedly suppressed by the treatment with PGE1 or PGE2.
4. In contrast PGF2α had no suppressive effect on renin substrate synthesis.
5. These findings suggest that PGE1 and PGE2 might be inhibitory factors in the regulation of renin substrate synthesis.