Dexamethasone induces the synthesis of a phospholipase A2-inhibitory protein (PLIP) of molecular weight -55,000 from calf thymus and PLIPs of molecular weights 55,000, 40,000, 28,000, and 15,000 from A/J mouse thymus and from 12-day embryonic B1O.A mouse palates. Sufficient quantities of calf thymus PLIP and of the 15,000 molecular weight mouse thymus and palate PLIPs were prepared and tested as inhibitors of programmed cell death in the medial-edge epithelium of single mouse embryonic palatal shelves in culture. All of the proteins tested prevent the loss of the medial-edge epithelium and, thus, produce the teratogenic effects of glucocorticoids in the palatal culture model. This teratogenic action of both PLIP and glucocorticoids is reversed by arachidonic acid, the precursor of prostaglandins and thromboxanes, suggesting that PLIP mediates the effects of glucocorticoids by inhibiting phospholipase A2.Although glucocorticoids are known to produce cleft palate in various mammals (1-5), little is known about the precise mechanism by which they produce their teratogenic action. The degree of cleft palate produced by glucocorticoids is in direct proportion to their anti-inflammatory activity. The steroids act as a consequence of their binding to cytoplasmic receptor proteins, followed by the translocation of the ligand-receptor complex into the nucleus, which in turn affects transcription of various RNA species (6)(7)(8). It has been demonstrated recently that glucocorticoids induce their anti-inflammatory action by producing a protein that inhibits phospholipase A2, the enzyme that produces arachidonic acid from phospholipids (9-12). Thus, the availability of arachidonic acid, the substrate for prostaglandin and thromboxane biosynthesis, is reduced after exposure to glucocorticoids. The synthesis of this protein is mediated by the glucocorticoid receptor and is blocked by inhibitors of RNA and protein synthesis (12).The clefting action of glucocorticoids involves (i) a delay of the elevation of the embryonic palatal shelves from a vertical position to a horizontal position in vivo (13-16) and (ii) inhibition of palatal shelf medial-edge lysosomal enzyme activity and epithelial breakdown both in vivo (15,16) and in single embryonic palatal shelves in vitro (15,16). Glucocorticoid-induced palatal teratogenicity can be corrected significantly by arachidonic acid in the rat (17) and mouse (18,19) in vivo and in the mouse in vitro (18,19). The corrective effect of arachidonic acid can be prevented by indomethacin, an inhibitor of cyclooxygenase, in vivo and in vitro (17-19). These results indicate that glucocorticoids inhibit the release of arachidonic acid and prevent the subsequent production of prostaglandins or thromboxanes, or both, in the induction of cleft palate, thereby paralleling their anti-inflammatory action. This led us to postulate that the teratogenic action of glucocorticoids may be mediated also by the production of phospholipase A2-inhibitory proteins (PLIPs). In this paper, we report that t...

The diagnosis of 5 alpha-reductase deficiency was proven in two prepubertal patients with male pseudohermaphroditism (MPH). Both had a 46-XY karyotype and were reared as females; one child had been castrated in infancy. Clitoromegaly, urogenital sinus, and short vaginal pouch were present in both; inguinal gonads were palpable in one. The diagnosis was made biochemically by observing characteristic changes in five parameters: 1) abnormally high testosterone to dihydrotestosterone (T:DHT) ratio after hCG stimulation (35 and 53 vs. normal, 11 +/- 3), 2) abnormally high 5 beta-T metabolites in urine (8.1 and 6.0 vs. normal, less than 1),3) deficient conversion of T to DHT during [3H] T infusion (0.3 and 0.4% vs. normal, 5.3 +/- 3), 4) deficient conversion of [14 C] T to 5 alpha-reduced metabolites by nongenital skin fibroblasts (2.2 and 1.9 pmol/microgram DNA/nmol substrate vs. 68.4+/- 7.8 Pmol/microgram DNA/nmol substrate in normal controls), and 5) deficient conversion of [14C]T to DHT in genital skin slices. The fact that this syndrome represents a defect in T metabolism rather in in T binding is demonstrated by the observation that binding of [3H]DHT to cytosol of skin fibroblasts was normal (4.2 dpm/micrograms DNA vs. normal male values of 3.7 +/- 0.64). Thus, the present report suggests that 5 alpha-reductase deficiency can be diagnosed during childhood and even after castration by metabolic studies of nongenital skin fibroblasts and determination of the conversion ratio of [3H]T to [3H]DHT in plasma.

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