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Biomedical subjects

N Hartmann

Publications and source records attributed to N Hartmann.

29 records · Page 2Linked to original sources
PubMed1977

[Effect of protein content and thyroid hormone on body composition in growing rats].

The effects of an isocaloric control diet of high-protein and low-protein diets (in which protein amounted to 16, 62 and 2% of total calorie content, respectively) with and without simultaneous administration of Thyreotom or methylthiouracil on total body composition have been studied in growing male Wistar rats. In spite of higher average Kcal intake (per day and 100 g of body weight), the rats on the high-protein diet were weighing less than the control animals at the end of the experiment. As compared to the control animals, the rats on the high-protein diet as well as those on the low-protein diet showed a greater relative weight of the thyroid gland. The protein percentage of the body was not significantly increased by an increase in protein supply; likewise, it was not significantly reduced by a decrease in protein supply. The body fat content was by 2/3 lower in the rats on the lowprotein diet than in the control animals. This difference was statistically significant. Thyroid hormones (1 mug liothyronine + 4 mug levothyroxine/100 g body weight, administered orally for 3 weeks) produced a slight increase of body protein in the rats on the high-protein diet; they increased it significantly in the rats on the low-protein diet. Body fat was correspondingly reduced. Methylthiouracil reduces the body fat content in the control animals and in the rats on the high-protein diet; it increased the body fat content in the rats on the low-protein diet. Our results confirm the partial findings of human pathology and demonstrate clearly that nutritional diseases, especially protein deficiency, worsen considerably in case of concomitant disorders of thyroid hormone metabolism.

Animals↗
PubMed1977

[Total body analysis of rats with special regard to fat determination. Possibility of determining fat and proteins by calculation].

The authors present a method for the whole body analysis of rats which combines the animal body preparation according to Mickelsen with the lipid analysis according to Folch; the liquid analysis has been somewhat modified. In this way and by the non-gutting of the animals, the determination of the body fat becomes less laborious. The body fat content can also be calculated from the water content. The body water content was determined gravimetrically. The body protein content was determined according to Kjeldahl; the protein content may also be calculated from the fat and water contents if an error range of +1% is acceptable.

Animals↗
PubMed1977

[Effect of degree of experimentally induced hypothyroidism on changes in serum albumin spectra in rats].

Extreme rat hypothyreosis of identical degree was induced by radiothyroidectomy (group R-HT) and feeding of thyreostatics (groups MTU-HT and MMI-HT). External signs, growth kinetics, serum cholesterol, thyroid weight, and the iodothyrosine pattern of the thyroid glands served as references for the quality of the hypothyreotic state. Determinations of following changes (all changes significant for p less than 0.001): 1. Higher total serum protein levels in hypothyreotic rats 4 and 7 weeks after beginning the experiemnts as compared to the controls (KT). 2. After 4 weeks the relative albumin content was diminished, the relative gamma-globulin content was elevated as compared to the KT. The absolute values of albumines did not change, alpha-1-globuline and gamma-globuline contents were increased in all hypothyreotic groups. 3. After 7 weeks normal albumine values, increase of the relative and absolute alpha-1-globuline content, and decrease of the relative beta-globuline concentrations were measured. Elevated gamma-globulins were found in MMI-HT and R-HT only, and an increased absolute albumine content in MTU-HT alone. The results confirm both hyperproteinemia and dysproteinemia as characteristics of the rat hypothyreotic state. Dynamic changes of absolute and relative contents of different serum protein fractions are demonstrated in relation to the duration of hypothyreosis. This fact can possibly explain contradictory findings on type of dysproteinemia by several authors.

Animals↗
PubMed1976

[In vitro study of deiodination of L-diiodotyrosine and L-thyroxine in liver of dietetically fat rats].

Beginning with the fifth week of life, male Wistar rats were fed a diet containing, respectively, 3 and 50 per cent fat (corresponding to, respectively, 7 and 75 per cent fat of total calories). The differences in body weight between the two groups were 64 per cent for 10-week-old rats, and 71 per cent for 6-month-old rats. For these animals, the extent of the enzymatic deiodination of L-diiodotyrosine and L-thyroxin was determined in liver homogenate supernatants. In the 10-week-old rats as well as in the 6-month-old rats on high-fat diet, the deiodination of L-di-iodotyrosine was significantly lower than in the animals on low-fat diet, whereas the diodination of L-thyroxin was significantly higher. It is concluded that the fat content of the diet exerts an inhibiting effect on the deiodination of L-di-iodotyrosine and an enhancing effect on the deiodination of L-thyroxin.

Age Factors↗
PubMed1976

[Effect of diet on deiodination of L-diiodotyrosine and L-thyroxine in rat liver].

Male Wistar rats of same weight were used to study the effects of diets containing, respectively, 3 and 50 per cent (by weight) fat on the deiodination of L-di-iodotyrosine and L-thyroxin in the liver. For this purpose, liver homogenate supernatants were analysed. The deiodination of L-di-iodotyrosine was significantly lower in the animals on high-fat diet than in those on low-fat diet, whereas the deiodination of L-thyroxin was significantly higher. It is concluded that not the body weight, but the diet influences the extent of deiodination.

Age Factors↗
PubMed1975

[Deiodase activity in hypothyroid rats].

In rats hypothyroidized with methylthiouracil (MTU), methimazol (MMI), or radiothyroidectomy, the extent of deiodination for L-diiodotyrosine (L-DIT) and L-thyroxine (L-T4) was investigated in homogenate supernatants of liver and kidney. Deiodination in liver and kidney for DIT is twice as high as for T4, but the kidney allows only 25% of the liver deiodination activity both for DIT and T4. In the livers of all hypothyroid animals, iodide splitting both from DIT and T4 is highly significantly reduced by one-half compared with controls. In the kidney of all hypothyroid animals, the DIT deiodination is highly significantly lowered in comparison with controls; the T4 deiodination is significantly reduced only in animals treated with MTU and MMI, and is not significantly enhanced in radiothyroidectomized rats. Thus, there is no difference between MTU and MMI in the extent of deiodination for DIT and T4 in the homogenate supernatants of rat liver or kidney.

Animals↗
PubMed1975

[Deiodination in the kidney and thyroid function)].

In homogenate supernatants of kidneys of male rats the extent of deiodination of L-diiodotyrosine (L-DJT) and L-thyroxine (L-T4) was investigated in dependence on the thyroid function (hypo- and hyperthyroidized) and also in dependence on age. In rats hypothyroidized by loading with Methylthiouracil (MTU) or Methimazol (MMI) the deiodination for L-DJT and L-T4 was significantly reduced, in rats loaded with 40 mug T4 sc. for 10 days, the deiodination was significantly enhanced compared with untreated control animals. With advancing age (6 weeks, 3 or 12 month) the deiodination activity is highly significantly reduced. The results underline relations between thyroid gland function and deiodination activity in kidney.

Age Factors↗
PubMed1975

[Deiodase activity in rats following an overdose of thyroid hormone].

The L-DIT and L-T4 deiodinating activity in supernatants from liver or kidney homogenates of normal rats or rats loaded with T4, T3 or TSH, was investigated. Deiodination of L-DIT occurs in liver supernatants twice as much as in liver, referring to mg of protein of g of tissue, while the deiodination of L-T4 seems rather equal. The over all rate of deiodination, however, reaches in liver for L-DIT the threefold, for L-T4 the fivefold value, as compared with kidney. Short periods of loading do not alter deiodination of L-DIT in liver or kidney at all; but lead to significant elevation of L-T4-deiodination in liver tissue. Higher doses or longer periods of loading cause a significant rise of L-DIT-deiodination in liver and kidney, while the L-T4-deiodination in liver is significantly decreased and in kidney significantly elevated.

Animals↗