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Biomedical subjects

T Pribyl

Publications and source records attributed to T Pribyl.

At least 37 records · Page 2Linked to original sources
PubMed1982

Acute and chronic vitamin C deficiency in guinea-pigs: its effect on ceruloplasmin and cytochrome P 450 and b5 levels.

Serum and liver ceruloplasmin levels rose markedly in guinea pigs with acute scurvy and with chronic latent scurvy. Their increase in the former condition can be attributed to the general stress reaction, but the increase in ceruloplasmin levels in concentration may have a stimulant effect on the ceruloplasmin, when the oxidation of Fe2+ to Fe3+ is potentiated, may obstruct the binding of iron to protoporphyrin and prevent formation of the haeme of cytochrome P 450 and b5.

Animals↗
PubMed1982

Aminoglutethimide, an inhibitor of adrenal steroidogenesis, blocks heart growth after ligation of the abdominal aorta and in hyperthyroidism in rats.

With reference to the indirect evidence showing that heart growth in the presence of a cardiac overload is modulated by the adrenal cortex, we studied heart reactions to overloading (ligation of the abdominal aorta or hyperthyroidism) with simultaneous administration of aminoglutethimide, an inhibitor of steroidogenesis. Aminoglutethimide (Elipten CIBA, 0.5% in the diet) markedly inhibited the growth reaction of the heart 14 days after ligation of the abdominal aorta (reducing the aortal blood flow to about 40%) or after the administration of dried thyroid (Thyreoidin SPOFA, 0.2% in the diet). The effect of aminoglutethimide is evidently not due to its simultaneous antithyroid action, because methylthiouracil (Alkiron SPOFA, 0.2% in the diet) did not limit heart growth after ligation of the abdominal aorta, despite its having a stronger goitrogenic effect than aminoglutethimide. The results are a further contribution to the series of indirect evidence of the modulating effect of the adrenal cortex on heart growth.

Aminoglutethimide↗
PubMed1981

Correlations between adrenal weight and heart weight in rats with a cardiac overload.

A significant positive correlation between heart weight and adrenal weight was found in rats with myocardial hypertrophy induced by experimental hyperthyroidism or ligation of the abdominal aorta. The simultaneous administration of digitoxin partly inhibited myocardial hypertrophy after ligation of the abdominal aorta, but not after experimental hyperthyroidism. Digitoxin also inhibited adrenal hypertrophy after ligature of the abdominal aorta but, again, not after experimental hyperthyroidism. The possible existence of an endogenous cardiotropic hormone participating in the development of cardiac hypertrophy from overloading is discussed.

Adrenal Glands↗
PubMed1981

Digitalis-like biological activity and immunoreactivity in chromatographic fractions of rabbit adrenal extract.

Dichloromethane extract of rabbit adrenals was subjected to thin-layer chromatography (Kieselgel 60F-254, MERCK) and digoxin immunoreactivity and digitalis glycoside-like biological activity were determined in the fractions by homogeneous enzymoimmunoassay and by inhibition of 86Rb uptake by red blood cells in vitro, respectively. Both the immunoreactivity and the biological activity maximum were present in two fractions which moved (in chromatography) between the corticosterone and deoxycorticosterone and showed a different RF from the deoxycorticosterone and aldosterone. In association with previous findings on digoxin-like immunoreactivity in the serum of animals with a cardiac overload, the possible existence of a cardiotropic steroid of adrenocortical origin is suggested.

Adrenal Glands↗
PubMed1980

Correlations between adenohypophyseal weight, serum polyphenol oxidase activity (ceruloplasmin) and hypothalamic ascorbic acid after estrogen treatment in rats.

Serum polyphenol oxidase activity (ceruloplasmin) and the hypothalamic ascorbic acid concentration were determined in control rats and rats given estradiol for 2-6 months. A significant positive correlation (r = 0.5948, p less than 0.001) was found between adenohypophyseal weight and the ceruloplasmin level and a negative correlation between adenohypophyseal weight and the ascorbic acid concentration in the hypothalamus (r = -0.5728, p less than 0.01) and between the hypothalamus ascorbic acid concentration and the ceruloplasmin level (r = -0.7059, p less than 0.01). The ways in which an increase in serum polyphenol oxidase activity might modulate the adenohypophyseal reaction to estradiol are discussed.

Animals↗
PubMed1980

Reactions of hypothalamic ascorbic acid, serum ceruloplasmin and the adenohypophysis to oestradiol: inhibition by L-thyroxine.

Four weeks' administration of oestradiol benzoate to male and female rats in doses of 1 mg twice a week leads to adenohypophyseal hyperplasia and to an increase in the thyroxine-binding capacity of the adenohypophyseal proteins in vitro. At the same time, serum polyphenol oxidase (ceruloplasmin) activity rises and the hypothalamic ascorbic acid concentration falls. The simultaneous administration of L-thyroxine (0.1 mg/rat/per day) or dried thyroid (but not D-thyroxine) significantly inhibits these changes (adenohypophysis, ceruloplasmin) or completely suppresses them (hypothalamic ascorbic acid). L-thyroxine evidently blocks the action of oestradiol in the adenohypophysis, the liver and the hypothalamus; the significance of this inhibition is discussed in relation to dopaminergic modulation of the adenohypophyseal reaction to oestradiol.

Adrenal Glands↗
PubMed1980

Dopaminergic modulation of the adenohypophyseal reaction to oestradiol: interaction of perphenazine with the thyroid hormones.

In male and female rats, oestradiol raises adenohypophyseal weight, the thyroxine-binding capacity of the adenohypophyseal proteins and the blood ceruloplasmin (polyphenol oxidase) level and reduces the ascorbic acid concentration in the hypothalamus. Simultaneous administration of the thyroid hormones inhibits all these reactions. The simultaneous administration of perphenazine (a dopaminergic neurone inhibitor) potentiates the adenohypophyseal and ceruloplasmin reaction, but does not modify the hypothalamic ascorbic acid reaction. Perphenazine combined with the thyroid hormones blocks the latters' inhibitory effect on the adenohypophyseal, ceruloplasmin and hypothalamic ascorbic acid reaction to oestradiol. The possible mechanisms by which perphenazine blocks the inhibitory effect of the thyroid hormones are discussed.

Animals↗