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Biomedical subjects

H P Roth

Publications and source records attributed to H P Roth.

At least 73 records · Page 4Linked to original sources
PubMed1975

Carbonic anhydrase activity and erythrocyte count in the blood of zinc-deficient rats.

Eighteen male Sprague Dawley rats were divided into three groups. They were offered a semisynthetic casein diet containing either 1.2 mg Zn/kg dry matter (depletion group) or 100 mg Zn/kg dry matter (ad libitum and pair-fed control groups). At the beginning and on the 5th and 24th day of the experiment, blood was removed from a tail vein by incision to determine erythrocyte count and carbonic anhydrase activity. The zinc-depleted animals displayed a great increase in erythrocytes during the course of the experiment as compared to the ad libitum control animals. The erythrocyte counts of the pair-fed animals were also increased after 24 days on experiment, but remained significantly lower than those of the depleted animals. The activity of the carbonic anhydrase per ml blood was the same in all groups at the end of the experiment. When, however, the carbonic anhydrase activity was expressed per unit of erythrocytes, the zinc-deficient animals had a significantly lower enzyme activity than both the ad libitum and the pair-fed control rats.

Animals↗
PubMed1975

[Effect of zinc deficiency on glucose tolerance].

18 male rats (Sprague Dawley) were divided into 3 groups each receiving the following amounts of dietary zinc: 2 mg/kg in the depletion group and 100 mg/kg in both the ad libitum-fed control group and in the pair-fed control group. After 34 days of experiment the rats were fasted for 12 hrs and then received 50 mg of glucose per 60 g of body weight injected into the femoral muscle. With equal intial glucose concentrations Zn-depleted rats exhibited a significantly reduce glucose tolerance compared with that of the ad libitum-fed control animals. The reduced glucose tolerance in the Zn-deficient animals does, in this case, not arise as a result of the reduced food intake and the resulting weakened condition of the animals. This was shown by results obtained with the pair-fed animals exhibiting a significantly more stable glucose tolerance than the Zn-depleted rats, which was even more rigid than that of the ad libitum-fed controls.

Animal Feed↗
PubMed1975

[Determination of metabolic availability of zinc and estimation of zinc requirements through changes in the activity of metallo-zinc enzymes].

Data on the zinc requirements of animals vary widely with the type of diet or kind of zinc compound considered, as they are dependent on the kind of definition and estimation of mineral requirements used which, in turn, are based on the analytical content of the mineral in the diet. Actually, requirements for a particular trace element are the same for any diet provided differences in the rate of absorption and metabolic availability of the element are taken into consideration. A suggestion is made in the present paper to utilize changes in the activity of different metallo-zinc enzymes as a method for determining the degree of metabolic availability of zinc. Within the framework of a repletion trial young male rats were fed a semisynthetic casein diet containing 1.2 ppm of zinc for a 14-day period of zinc depletion followed by a 15-day repletion period during which the rats received a diet containing 4.5 ppm or 12 ppm of zinc. In this trial the pattern of activity of the alkaline phosphatase in serum and in the femoral bones was studied and the level of pancreatic carboxypeptidase A and B was estimated. The data thus obtained were compared with those of pair-fed control animals and control animals fed a libitum. (96 ppm of dietary zinc). The results of the present trial show the metabolic availability of zinc can be determined by measuring the level of activity of these metallo-zinc enzymes. A suitable model was established. Moreover, attempts have been made to show in which way the zinc demands of growing, full-grown, pregnant and lactating animals may be estimated by measuring changes in the degree of activity of these metallo-zinc enzymes. A definition is, in this case, given by that amount of zinc which allows for an optimum activity of the different metallo-zinc enzymes. Such data are applicable only to a particular diet or are valid only for a particular zinc compound. Principally, it is much better to relate the Zn requirements of the animal to the level of absorbable and metabolically available zinc. The present model has been suggested to provide a possibility for measuring the metabolic availability of zinc in the body.

Alkaline Phosphatase↗
PubMed1975

[Serum and plasma insulin levels in zinc-deficient rats following glucose stimulation].

In three experiments male Sprague-Dawley rats depleted in zinc (2 ppm dietary zinc) for 30 to 35 days had greatly reduced serum insulin levels when compared to ad libitum-fed control animals (100 ppm dietary zinc) but in only one of the experiments when compared to pair-fed control animals (100 ppm dietary zinc) which also had reduced insulin levels. Similarly, in a following study the plasma insulin levels of zinc-deficient animals depleted for 20 days were not different from those of pair-weight control animals (100 ppm dietary zinc). Fifteen minutes after one i.m. glucose injection and 15 minutes after two glucose injections, two hours apart, the zinc-deficient rats showed a higher blood glucose level than the pair-weight controls. The plasma insulin contents also increased after the glucose stimulation but were not significantly different between the zinc-deficient and the zinc-supplemented groups. It is assumed that zinc deficiency lowers the physiological potency of insulin and thereby effects a reduced glucose homeostasis of zinc-deficient rats. This could also be demonstrated by additional studies with zinc-deficient rats which secreted 76 per cent more insulin after a Rastinon injection than control animals though they showed about the same bloodglucose levels.

Animals↗
PubMed1975

[Activity of the alkaline phosphatase in the serum and bones of zinc-deficient and zinc-replenished cows].

In a study with five lactating dairy cows fed a semisynthetic diet, the changes in the activity of the alkaline phosphatase in the serum, bones and milk were investigated in response to dietary depletion and repletion of zinc. During a six-week depletion period (6 mg Zn/kg dry matter) the alkaline phosphatase in the serum decreased to only 82% of its initial level which, however, was reduced already due to a low zinc intake before the start of the study. After 19 weeks of depletion the activity had decreased to 43% of its initial level. Additions of zinc during the repletion increased the activity very clearly and to much higher values than the ones at the start of the study. Thus this effect of repletion was as large as that for the zinc content in serum and milk. The serum alkaline phosphatase indicated a dependence on the performance and represents a sensitive indicator of the zinc status. The activity of the alkaline phosphatase in the bones (Tuber coxae) decreased to 68% of its initial level after six weeks of zinc depletion. The alkaline phosphatase in the milk was not influenced by the zinc supply.

Alkaline Phosphatase↗