Amount Of Creatine Research Articles

Estimating the dosage and feasibility of intranasal administration of creatine.

Creatine dysregulation is present in many psychiatric and neurocognitive conditions, supporting the notion that oral creatine supplementation could constitute a viable treatment for conditions such as dementia, depression, and concussion. We recently proposed an intranasal route of administration (ROA) of creatine as a means of efficiently dosing creatine to achieve absorption across the blood brain barrier while targeting preferential delivery to the brain. Indeed, a subsequent murine study supports that creatine can be absorbed via the nasal ROA. The objective of this project is to refine this ROA and estimate appropriate dosage for research trials. The amount of creatine needed to directly supply the brain is but a small portion of the dose that is administered orally for whole-body saturation. A single dose of creatine is typically 5 g, which results in a calculated blood concentration of 80 mg/dL based upon average adult blood volume. Evidence suggests this is sufficient to raise brain creatine levels. Given the adult brain blood volume of 100‒130 mL, we estimate that a minimum of 80 mg of nasally-administered creatine would need to pass from the nasal cavity across the blood-brain barrier. Even if the nasal columnar epithelium or mucus were to pose a barrier, doubling or tripling the dose would still represent a relatively modest amount of nasally-delivered creatine (e.g., 160‒240 mg) in solution. We predict that the amount of nasally-administered creatine to theoretically raise brain blood concentration to a therapeutic level would be modest and practical.

Supplemented Creatine Induces Changes in Human Metabolism of Thiocompounds and One- and Two-Carbon Units

The administration of creatine (5 g/day for one month) to 11 young active sportsmen affected their urinary excretion of creatine, creatinine, and thiodiglycolic acid (TDGA) as well as blood levels of homocysteine, vitamin B12 and folates. The probands were divided into four groups, according to the amount of creatine found in urine, and of folates and vitamin B12 determined in blood. The changes of folates and vitamin B12 were mutually reciprocal. Each group utilized CR as donor of one- and two-carbon (1C and 2C) units by means of homocysteine (HoCySH), folates, and vitamin B12, in different metabolic pathways. In 10 men the creatine administration was accompanied by an increase of HoCySH level in blood, while in the last man, with accidentally discovered hyperhomocysteinemia, the HoCySH level dropped by 50%. Differences between initial and terminal TDGA levels indicate that creatine affects equilibria of redox processes. Creatinine excretion into urine changed in the dependence on the extent of metabolic disturbances.

A New Method for Isolation of Reticulocytes: Positive Selection of Human Reticulocytes by Immunomagnetic Separation

A method for isolating pure reticulocytes from leukocyte-depleted blood of normal persons is presented. The separation was achieved using an immunomagnetic technique. A monoclonal mouse antibody against human transferrin receptor was bound to magnetic beads conjugated with sheep antimouse antibody. The recovery of reticulocytes from peripheral blood was 15% to 42%. Blood used for isolation of reticulocytes could be stored for 4 days at 22 degrees C without altering the yield of reticulocytes. At 37 degrees C incubation, the reticulocytes matured rapidly and the transferrin receptor was found to have a half-life of 16 hours. The activity of several enzymes and the amount of creatine and hemoglobin A1C were measured both in the reticulocytes and peripheral blood. Of the enzymes, porphobilinogen deaminase had the best discriminatory power with a ratio of 8.8 between reticulocytes and peripheral red blood cells. The ratio for creatine was 16.7. The ability to isolate pure human reticulocytes, released after normal erythropoiesis, will offer new possibilities in the study of these cells.

A new method for isolation of reticulocytes: positive selection of human reticulocytes by immunomagnetic separation

A method for isolating pure reticulocytes from leukocyte-depleted blood of normal persons is presented. The separation was achieved using an immunomagnetic technique. A monoclonal mouse antibody against human transferrin receptor was bound to magnetic beads conjugated with sheep antimouse antibody. The recovery of reticulocytes from peripheral blood was 15% to 42%. Blood used for isolation of reticulocytes could be stored for 4 days at 22 degrees C without altering the yield of reticulocytes. At 37 degrees C incubation, the reticulocytes matured rapidly and the transferrin receptor was found to have a half-life of 16 hours. The activity of several enzymes and the amount of creatine and hemoglobin A1C were measured both in the reticulocytes and peripheral blood. Of the enzymes, porphobilinogen deaminase had the best discriminatory power with a ratio of 8.8 between reticulocytes and peripheral red blood cells. The ratio for creatine was 16.7. The ability to isolate pure human reticulocytes, released after normal erythropoiesis, will offer new possibilities in the study of these cells.

Effect of Thyroparathyroidectomy on Radiation-Induced Creatinuria in Rats

Thyroparathyroidectomized rats and sham-thyroparathyroidectomized rats were exposed to 500 r of whole-body x irradiation. Twenty-four-hour urine samples were collected for three days before exposure to x irradiation. Samples of blood from the tail veins were also collected at various time intervals. The degree of creatinuria was assessed by means of the daily urinary excretion of creatine, The results indicate that the thyroid gland affects radioinduced creatinuria at a whole-body exposure dose of 500 r only slightly but that certain differences, namely the negative correlation between the urinary creatine excretion and the erythrocyte creatine concentration and the depression of creatinine excretion on the first postexposure day, exist in the thyroparathyroidectomized group. The amount of creatine and creatinine excreted daily in both the thyroparathyroidectomized and sham-thyroparathyroidectomized rats is related to the amount of daily urinary volume. (auth)

HYPOTHYROIDISM IN CHILDHOOD. II. SENSITIVITY TO THYROID MEDICATION AS MEASURED BY THE SERUM CHOLESTEROL AND THE CREATINE EXCRETION1

IN THE FIRST PAPER of this series, the writers (i) pointed out the difficulties involved in diagnosing hypothyroidism in the untreated child by a study of the basal metabolic rate, serum cholesterol and ereatine excretion. It was shown that the measurement of the basal caloric requirement was often impossible in children, and that, even when it could be measured accurately, the determination of the deviation from the normal was often an unsatisfactory means of diagnosis. Although the concentration of serum cholesterol was high in many untreated hypothyroid children, in some cases it was within the normal range. The amount of creatine excreted by hypothyroid children was usually small, but the output was just as small in many normal children of the same age. Magnus-Levy (2) first demonstrated that hypothyroid patients show more marked effects from small doses of thyroid than normal individuals. It is generally recognized that doses of desiccated thyroid as small as ½ grain to 2 grains (32 to 128 mg.) daily...

CREATINE-CREATININE METABOLISM AND THE HORMONES II. PROGESTIN AND ANTUITRIN-T11

IN THE first study in this series (I) results were published showing that castration in both sexes of young adult white rats resulted in creatinuria which was more intense in the female than in the male. The injection of anterior pituitary hormones (G, T and S), theelin, follutein, and testosterone propionate, caused increases in muscle creatin and in creatin excretion accorripanied by decreases in creatinine excretion. The injection of all these hormones, with the exception of antuitrin‚S and T and of follutein, caused a more significant increase in the total amount of creatine excreted in the castrated rat than in the same rat before castration. A possible synergistic action of the hormones in the body upon creatine and creatinine metabolism was suggested. In the present study progestin and antuitrin-T, and theelol with antuitrin‚S, were injected into normal and castrated female rats. The experimental procedures were given in our first paper of this series (I).

STUDIES IN DISEASES OF MUSCLE

In a previous report 1 we discussed various factors influencing the ability of patients with progressive muscular dystrophy to retain ingested creatine. In the series of twenty cases investigated the creatine tolerance was impaired so that a large part of an administered dose of creatine was excreted unchanged in the urine. The defect in the ability to retain exogenous creatine varied with the degree of muscular disability. In adult patients in the early stages of the disease as much as 82 per cent of the ingested creatine was retained, whereas in patients showing advanced muscular wasting the creatine tolerance was impaired to the extent that all the ingested dose of creatine was excreted unchanged. The amount of creatine usually administered in performing the creatine tolerance tests in our studies was 1.32 Gm. However, other workers have used widely different amounts. Thus, Boothby and his associates 2 gave 1 Gm.; one

Further studies on muscle creatine

In an earlier communication,1 attention was called to the constancy in the content of muscle creatine for normal animals of a given species, though distinctive for different animals. It was further pointed out that during starvation in the rabbit, the percentage content of muscle creatine may show either an increase or a decrease, the latter depending in considerable part upon the rate and amount of creatine eliminated in the urine.These observations have been extended to rabbits which have been fed for varying periods upon carbohydrate—without fat or protein. Carbohydrate feeding greatly reduces the elimination of creatine in the urine, as previously observed, though the creatine content of the muscle does not materially differ from that found during a similar length of starvation. In other words, it may be markedly decreased during a long period of carbohydrate feeding. It seems probable that the action of the carbohydrate is simply one phase of the sparing action of carbohydrate on protein metabolism, ...