Impaired inner medullary production of prostaglandin E2 in the kidney of the myxedematous rat.

Renal cAMP concentration and renal prostaglandin (PG) E2 and PGF2alpha production were determined in control rats and rats with surgically induced myxedema. Slices from the kidneys of each group were incubated in vitro. cAMP concentration of inner medullary slices from the kidneys of myxedematous rats was decreased in comparison to slices from control rats. There was no difference between the two groups when slices from outer medulla and cortex were compared for cAMP level. In myxedema, there was decreased inner medullary production of PGE2, but not PGF2alpha. The difference in PGE2 production between myxedema and control rat kidneys was not corrected by addition of either arachidonic acid (170 micronM) or phospholipase A2 (5 microgram/ml). Arachidonic acid, however, increased inner medullary cAMP concentration in myxedema kidneys to a value not measurably different from control. Thus, there appears to be a decreased PGE2 production in the renal inner medulla of rats with myxedema. In view of the fact that PGE2 has previously been shown to increase inner medullary cAMP content, the reduced inner medullary content of cAMP would appear to be attributable to reduced PGE2 production.