Effect of oral feeding of 14, 400, 28, 800, 57, 600 and 93, 600 l.u. of retinol respectively daily for 10 days on the adrenal lipids of adult rats has been studied. Feeding of different amounts of retinol enlarged the adrenal glands, and brought about marked elevations in adrenal total lipids, esterified and free cholesterol, triglycerides and all the phospholipids.

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Thiamine and its derivatives, thiamine tetrahydrofurfuryl disulfide (TTFD), thiamine allyl disulfide (TAD), thiamine propyl disulfide (TPD), and methylthiamine propyl disulfide were investigated for the effects on atrial contractions of guinea-pig in relation to those of quinidine and potassium and the following findings were obtained.
1. Atrial contractions arrested by high concentrations of potassium were restored by the addition of TTFD. Strophanthin-G also showed this kind of effect.
2. In a postassium-free Locke's solution atrial contractions were arrested within 30 to 90 minutes, but in the presence of TTFD arrest was delayed. This effect of TTFD was similar to that of quinidine.
3. Atrial contractions arrested by the presence of quinidine were restored by the addition of TTFD.
4. The depressive effect of nicotine in the earlier stage were suppressed by the presence of TTFD.
5. The relation between TTFD and endogenous as well as exogenous catecholamine could not be proved.
6. TAD and TPD also showed effects similar to those of TTFD on quinidine and potassium. The effect of thiamine itself, though similar to that of TTFD, was very weak, but that of methylthiamine propyl disulfide, an antithiamine, was stronger than TTFD against quinidine and potassium.
From these results it is considered that TTFD, TAD, TPD, and methylthiamine propyl disulfide may reduce not only influx but also efflux of potassium at the excitable cell membrane.

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A modified enzyme method for the simultaneous estimation of urinary formiminoglutamic acid (FIGLU) and urocanic acid after a loading with 15g of L-histidine has been applied to 10 normal subjects and 40 patients with various blood disorders. The 24-hour excretion of the two derivatives in normal subjects was within 30mg for each of them and within 60mg for the combined two derivatives. FIGLU in excess was found in 45% of 40 patients, and urocanic acid in excess, in 40% of 25 patients. All of six patients whose hematopoieses were megaloblastic excreted excessive FIGLU or the combined two derivatives. Out of 12 cases in whom the total amount of histidine derivatives exceeded the normal range of 60mg, 11 cases were in excess of FIGLU, and 10 cases, of urocanic acid excretion; 3 cases excreted only FIGLU in excess, and 3 cases, only urocanic acid in excess. Out of these 12 cases, six cases excreted both FIGLU and urocanic acid in excess, and urocanic acid was the predominant constituent in one patient. These results suggested a wide-spread existence of folic acid deficiency in blood disorders, and simultaneously, supported the value of estimating both the histidine derivatives for detecting folate deficiency in humans.

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Urinary excretion of formiminoglutamic acid (FIGLU) and urocanic acid was observed in patients with various neoplastic diseases. Using these histidine derivatives as an index, serial observations have been made mainly on the toxic effect of several dose schedules of methotrexate (MTX) in tumor-bearing patients and normal animals. The dosage schedules of MTX comprised a single large dose, intermittent large doses, and arterial infusion in patients and a single large dose and divided doses in animals.
Of 40 untreated patients with various neoplastic diseases, 19 excreted an abnormal amount of FIGLU, 11 of urocanic acid, and 20 of the combined derivatives in the urine. The serial observations of urinary histidine derivatives under MTX treatment revealed following evidences; (a) the excreted amount of the derivatives in maximum level was well proportional to the size of dose of MTX in single injection, (b) the severity of the clinical signs, the toxicity of MTX, was in parallel with the amount of the derivatives excreted in the urine, and (c) the beginning of increase of the derivatives preceded that of decrease in white blood cell count, if accompanied, in all the cases.

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