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Biomedical subjects

J Blahos

Publications and source records attributed to J Blahos.

At least 73 records · Page 4Linked to original sources
PubMed1981

Effect of calcium on adrenocortical secretion.

The authors investigated the effect of calcium on the basal cortisol secretion and on the adrenocortical secretory reserve, the indicator of which is the so-called ACTH stimulation test. They revealed that during acute hypercalcaemia there is a significant increase of the basal cortisol secretion. The adrenocortical secretory reserve is significantly reduced during hypercalcaemia, this being manifested by a smaller rise of cortisolaemia after ACTH. The Synacthen test repeated after a 48-hour interval is fully reproducible under normocalcaemia. The basal values and the response to Synacthen do not differ from the control examination. The stimulatory action of calcium can be explained indirectly via other humoral factors, the production of which is enhanced by calcium but also the function of calcium which acts as the so-called "second messenger" in steroidogenesis. Calcium has, however, probably also a direct corticotropic effect, resembling that of ACTH.

Adrenal Cortex↗
PubMed1981

Hypercalcemia influences TRH-stimulated TSH and T3 response.

The influence of acute hypercalcemia induced by i.v. infusion of calcium gluconate on basal TSH and T3 levels in plasma and on their response to TRH stimulation (TRH test) was investigated in 10 healthy subjects. TRH test under normal conditions without hypercalcemia was carried out in the same subjects. Under acute hypercalcemia the basal T3 levels were evaluated markedly up to levels occurring after TRH stimulation. However, the relative increase of T3 following TRH challenge was of the same degree as in normocalcemia. Basal TSH levels did not differ from those found under normocalcemia, but the response to TRH was decreased. The results suggest that hypercalcemia affects the mechanisms regulating the levels of the thyroid hormones and TSH.

Adult↗
PubMed1981

Alternate-day betamethasone treatment does not affect intestinal absorption of calcium and phosphate and growth rate of chicks.

The effect of oral administration of betamethasone in single daily doses (25 microgram kg-1 d-1) and in single alternate-day doses (50 microgram kg-1 every other day) on the duodenal absorption of calcium, on the jejunal absorption of phosphate and on weight gain has been studied in chicks using the in vivo ligated loop technique. The daily administration of betamethasone for three weeks markedly reduced the absorption of calcium and phosphate as well as the growth rate. Alternate-day treatment lacked all these adverse effects of betamethasone and the results did not differ significantly from those in the control chicks.

Animals↗
PubMed1981

Influence of 25-hydroxyvitamin D3 on thyrotropin and triiodothyronine plasma levels in man.

The influence of three-day oral administration of 100 microgram 25-hydroxycholecalciferol (25-HCC) on thyrotropin (TSH), triiodothyronine (T3), calcium and phosphorus plasma levels was investigated along with changes of Qet and Qat intervals on the electrocardiographic tracing. It was found that 25-HCC in an acute trial significantly elevates the TSH level and causes a slight decline of the T3 level. Changes in the calcium and phosphorus levels were not significant. No changes of the electrocardiographic tracing were found. The results suggest that 25-HCC interferes with the process of secretion (or metabolization) of TSH (and perhaps also T3), probably via changes of the calcium ion concentration in cytosol of secretory cells.

Adult↗