Aroclor 1254 was administered intraperitoneally (25 mg kg body wt-I in 1 ml of arachis oil) at weekly intervals for 4 weeks to trout and carp; arachis oil was used as the control. Activities of the following hepatic microsomal enzymes, aminopyrine demethylase, pnitroreductase, UDP-glucuronyl-transferase and I-leucyl-P-naphthylamide splitting enzyme were measured in both species; cytochrome P460 and microsomal protein contents were also determined.The changes in the levels of androgens, oestrogens and corticoid hormones were measured in the circulating blood of control and treated groups at weekly intervals. The blood was obtained by cardiac puncture.Results indicated (a) a significant increase in the activities of all the enzymes measured except 1-leucyl-P-naphthylamide splitting enzyme, (b) cytochrome P450 and microsomal protein contents were increased in trout, but not in carp, (c) a significant reduction in the plasma levels of androgens, oestrogens and corticoids in the treated groups, particularly at the end of the fourth week and (d) there was a correlation between increased enzyme activities and a decrease in plasma hormone levels.

Sexually mature and 9 rainbow trout (Salmo gairdneri Richardson) and carp (Cyprinus carpio L.) were injected intraperitoneally with Aroclor 1254 (25 mg kg-' body weight in 1 ml of arachis oil) once weekly for four weeks. Arachis oil was used as the control. At the end of the fourth week, samples of the liver, testis and ovary were taken from treated and control fish and examined by light and electron microscopy. The light microscope study indicated that there was general vacuolation of the hepatocytes of trout but not carp; fragmentation of the developing oocytes but no observable changes in the testis. Electron microscopy study showed that there was enlargement of the rough endoplasmic reticulum of the hepatocytes, some damage to spermatozoa and proliferation of the smooth endoplasmic reticulum of the oocytes.

1The activities of some hepatic drug-metabolizing enzymes representative of the four major pathways for the biotransformation of drugs were estimated in diagnostic wedge biopsy specimens obtained from 22 patients with Hodgkin's disease. Twelve patients (nine males and three females) were not on prolonged pre-operative treatment with any known inducing drugs.In this group, hexobarbitone oxidase activity, cytochrome P450 and microsomal protein contents were in the same range as those reported by other workers. 2 Ten patients (five males and five females) were pre-operatively treated with phenobarbitone (90 mg daily) for at least seven days. This resulted in a significant increase of hexobarbitone oxidase activity, cytochrome P450 and microsomal protein contents when the phenobarbitone untreated and treated groups were compared as a whole and provides direct evidence of induction of hepatic mixed function oxidase system. In respect of p-nitroreductase, I-leucyl-f-naphthylamide splitting enzyme and UDP glucuronyl transferase, there was no difference between the treated and untreated groups. 3 When untreated and treated patients were compared, the induction of the hepatic mixed function oxidase system, was associated with a significant increase in urinary D-glucaric acid excretion. In treated patients, however, there was no correlation between any of the indices studied and post-phenobarbitone D-glucaric acid content or the rise in D-glucaric acid excretion. However, the correlation between cytochrome P4so content and post-phenobarbitone D-glucaric acid or the rise in D-glucaric acid excretion was only just below statistical significance (r = 0.696 and 0.690 respectively, 0.10> P> 0.05) whereas in the untreated group there was no correlation (r = 0.231, P > 0.60). 4 In two patients, whose phenobarbitone was discontinued for at least six days prior to surgery, all indices studied had returned to untreated values, except the microsomal protein content which remained significantly elevated.