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Abstract. Bile acids and their sulphated and glucuronidated derivatives were studied in three children with persistent intrahepatic cholestasis, two children with intrahepatic biliary hypoplasia, and four healthy children. In children with cholestasis, biliary bile acids consisted of 11(±0–3) % 3 β‐hydroxy‐delta‐5‐cholenoic acid, 2‐1(± 0–6) % lithocholic acid, 2‐2(± 11) % deoxy‐cholic acid, 5–8(±2‐2) % ursodeoxycholic acid, 39‐1(± 1 ‐4) % chenodeoxycholic acid, 0–5(± 0 2) % hyo‐cholic acid, and 49‐3(± 3 0) % cholic acid. Of these bile acids 121 (±l 9) % were sulphated and 4–5 (±0 6) % were glucuronidated. In healthy children, biliary bile acids consisted of 0–7 (±0–4) % lithocholic acid, 3–4 (±0 8.) % deoxycholic acid, 0–1 (±0 1) % ursodeoxycholic acid, 32‐7 (±6 9) % chenodeoxycholic acid, and 631 (±7 1) % cholic acid. Of these bile acids, 0–6±0 1 % were sulphated and 0–2 ±0 1% were glucuronidated (mean ± SEM). In the urine of healthy children, 3‐3(±0 6) mg/24 h bile acids (1–5±0 3 mg sulphates and 0–1 ±0 1 mg glucuronides) were excreted, in the urine of children with cholestasis 61‐4 (± 10 2) mg/24 h (30 2 ±7 1 mg sulphates and 5 6 ±1 2 mg glucuronides) were excreted. Thus in children with cholestasis the amounts of sulphated and glucuronidated bile acids are greater than in healthy controls. Substantial amounts of sulphated and glucuronidated bile acids are excreted in bile and urine of these patients. Phenobarbitone treatment in the five children with cholestasis led to a reduction of serum bile acids from 90 4 (± 13 2) μg/ml to 39 3(±3 6) μ//ml, a relative increase of bile acid glucuronides in bile from 45 (±0 6)% to 8 l(±0 6)%, a slight alteration of the bile acid sulphates in bile from 121(±l 9) % to 111 (± 1 2)% and no alteration of the bile acid spectrum. Urinary excretion of bile acids decreased from 61 4 (± 10 2) mg/24 h to 34 7(±3 0) mg/24 h. Phenobarbitone treatment of children with cholestasis thus induced glucuronidation of bile acids but had no significant effect on sulphation or on formation of individual bile acids.

Glucuronides of lithocholate, chenodeoxycholate and cholate were synthesized enzymatically and characterized by thin layer chromatography, column chromatography and specific enzymatic hydrolysis. Bile salt glucuronides were quantitatively analysed in thr urine of patients with intra- and extra- hepatic cholestasis and were found to be present in 19 out of 20 patients studied. Our patients with intrahepatic cholestasis excreted 8.9 mg non-sulphated and non-glucoronidated bile salts, 18.2 mg sulphated bile salts and 7.2 mg glucuronidated bile salts. The patients with extrahepatic cholestasis excreted 14.7 mg non-sulphated and non-glucuronidated bile salts, 20.7 mg sulphated bile salts and 4.7 mg glucuronidated bile salts. These findings indicate that glucuronidation of bile salts occurs in man and represents a metabolic pathway in patients with cholestasis.

8-Aminolevulinic-acid-synthetase induction by drugs depends upon the nutritional state of the animal. I n allylisopropylacetamide-treated animals the enzyme induction is reduced in fed compared with starved rats whereas after phenobarbital treatment an induction of the enzyme seen in starved animals is not observed in fed rats. 8-Aminolevulinic-acid-synthetase induction is studied in relation to the synthesis of cytochrome P450.I n the isolated rat liver perfused with either rat blood or washed bovine erythrocytes and Eagle minimal essential medium, 8-aminolevulinic acid synthetase decreases sharply. This decrease can be prevented by the continuous addition of dexamethasone (9a-fluoro-l6a-methylpregna-1,4-diene-li,9,i7a,2l-triol-3,20-dione) or hydrocortisone (pregn-4-ene-l1,9,17a,21-triol-3,20-dione) but not by testosterone (androst-4-ene-178-01-3-one) or etiocholanolone (5P-androstan3a-ol-17-one). 8-Aminolevulinic acid synthetase cannot be significantly induced by allylisopropylacetamide unless corticoids are added to the perfusion medium. The results indicate that the synthesis of heme and, consequently, hemoproteins is controlled by corticoids or their metabolites in adult rat liver.Our interest in the mechanism(s) of cytochrome P450 induction by phenobarbital led us to the study of 8-aminolevulinic acid synthetase, because this rate limiting enzyme in heme biosynthesis is also induced rapidly and early after phenobarbital treatment [ I]. During hemoprotein formation heme and apoprotein synthesis have to be closely correlated if the intracellular heme pool is ony small. I n addition to phenobarbital, allylisopropylacetamide, the porphyria-producing moiety of the drug Sedormid, was studied as another compound affecting both enzymes-i. e. inducing d-aminolevulinic acid synthetase and, in contrast to phenobarbital, initially decreasing cytochrome P450 [2-41.I n the present study d-aminolevulinic-acid-synthetase regulation was investigated in livers in vivo and in the isolated perfused organ. The conditions for induction of the enzyme by allylisopropylacetamide and phenobarbital were first studied in intact rats.Since it was found that the induction of this enzyme by phenobarbital is a special event not seen in rats fed ad libitum, the studies in the isolated organ focusEnzyme. Tyrosine aminotransferase or L-tyrosine : 2-oxoglutarate aminotransferase (EC 2.6.1.5).Trivial Names. Etiocholanolone, 5B-androstan-3a-01-17-one; testosterone, androst-4-ene-17B-ol-3-one; hydrocortisone, pregn-4-ene-ll~,l7n,21-triol-3,20-dione; dexamethasone, 9a-fluoro-16a-methyl-pregna-1,4-diene-l1~,17a,21-triol-3,20-dione. sed on induction by allylisopropylacetamide. I n this system an induction comparable to that found in vivo could only be achieved after addition of corticoids to the perfusion medium. The dependence of8-aminolevulinic acid synthetase and consequently heme synthesis, upon corticoids will be discussed in relation to the induction of hemoproteins. I n addition, a model for 8-aminolevulinic-acid-synthetase induction by phe...

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