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Biomedical subjects

R Claus

Publications and source records attributed to R Claus.

At least 109 records · Page 6Linked to original sources
PubMed1982

Relationships between fat and plasma androstenone and plasma testosterone in fatty and lean young boars during growth and after hCG stimulation.

The effect of weight of fatty tissue on fat and plasma androstenone and on plasma testosterone relationships in the young boar was studied. For this purpose, hCG stimulation of steroid testicular production was performed in 12 boars and fat androstenone concentration subsequently measured. In addition plasma androstenone and testosterone were determined in 8 of them, previously cannulated. The results show that: 1) although plasma testosterone response to hCG stimulation was similar in all boars, fat and plasma androstenone responses were very variable between boars, 2) weight of fatty tissue appeared to have little influence, if any, on androstenone exchanges between plasma and fatty tissue and 3) plasma androstenone/testosterone ratio appeared to be less variable within boars than between boars. The data show that there is probably some between-boars-variability in the respective rates of elimination of testosterone and androstenone.

Adipose Tissue↗
PubMed1982

Relationships between fat and plasma androstenone and plasma testosterone in fatty and lean young boars following castration.

The effect of weight of fatty tissue on fat and plasma androstenone and on plasma testosterone relationships was studied in the young boar following castration. For this purpose, 9 boars were castrated at 175 days of age, plasma steroid levels were determined daily up to 10 days after orchidectomy and fat androstenone concentration was measured 1, 3, 6, 10 and 15 days after castration. The results show that the apparent half-life of stored androstenone is very variable between boars (range: 4 to 14 days) and do not depend on the weight of fatty tissue. The rate of elimination of plasma androstenone is also very variable between boars. The rate of disappearance of fat androstenone following castration does not depend on the rate of androstenone release from fatty tissue to peripheral plasma but is more likely dependent on the intensity of plasma androstenone catabolism and elimination. Therefore, fat androstenone concentration in the intact boar is almost only depending on the equilibrium between the respective rates of testicular production and elimination.

Adipose Tissue↗
PubMed1982

The in vitro effect of horse anti-human lymphocyte globulin on the electrophoretic mobility of human lymphocytes and platelets.

In accordance with earlier results the electrophoretic mobility of lymphocytes is decreased by horse anti-human lymphocyte globulin (AHLG), which correlates with the results of the rosette inhibition test. Under the influence of AHLG, the distribution of the electrophoretic mobilities of lymphocytes shows a characteristic change. In some of the AHLG samples, the antilymphocyte action is accompanied by an antithrombocyte effect. The resulting decrease in the electrophoretic mobility of platelets correlates with the thrombocytopenic effect in vivo. The variation of pH or ionic strength leads to changes of the AHLG effects. The in vivo influence of AHLG on the distribution of the electrophoretic mobility of peripheral blood lymphocytes and platelets is discussed.

Animals↗
PubMed1981

Histochemical and spectrophotometric demonstration of hydroxysteroid dehydrogenase activity in the presumed steroid producing cells of the brook lamprey (Lampetra planeri Bloch) during metamorphosis.

Pronephric, opisthonephric, ovarian, and testicular tissue rich in presumed steroid producing cells taken from the brook lamprey during metamorphosis was investigated by histochemical and spectrophotometric methods. Histochemical results seemed to provide evidence for hydroxysteroid dehydrogenase activity using pregnenolone as substrate. Spectrophotometric evidence for hydroxysteroid dehydrogenase activity was obtained from presumed adrenocortical tissue, ovarian and testicular homogenates using pregnenolone, dehydroepiandrosterone, androsterone, and 3 beta, 17 beta-dihydroxy-5 alpha-androstane as substrates.

Animals↗
PubMed1980

Influence of growth phase and carbon source on the content of rubredoxin in Acinetobacter calcoaceticus.

The rubredoxin content of Acinetobacter calcoaceticus in dependence on the carbon source (acetate, n-alkanes, succinate, L-malate) and on the growth phase was studied by means of a radioimmunoassay. The method used was specific for rubredoxin and Acinetobacter calcoaceticus. The formation of rubredoxin increased with time up to the end of the logarithmic phase when n-alkanes were the sole carbon source. After growth of Acinetobacter calcoaceticus on non-hydrocarbon substrates, rubredoxin was not detected.

Acinetobacter↗
PubMed1980

Oestrogens, compared to other steroids of testicular origin, in blood plasma of boars.

Oestrogens, testosterone, and 5 alpha-androstenone ('boar taint steroid') were determined in peripheral and spermatic vein blood plasma of boars. Oestrone was the predominant steroid in both the conjugated and the unconjugated fractions of total oestrogens. Concentrations of conjugated oestrogens in peripheral plasma generally are in the range of several nanograms/ml, which is similar to the range of 5 alpha-androstenone and testosterone. Unconjugated total oestrogens are in the lower nanogram-range. These concentrations, however, are still higher than those during the oestrus in sows. Stimulation with hCG led to increased concentrations of peripheral plasma oestrogens, demonstrating their testicular origin. Comparative measurements in spermatic vein plasma and peripheral plasma show that in general the testis has to secrete different amounts of the individual steroid to maintain the appropriate peripheral level. A highly correlated course of all the steroids measured was apparent. This was shown for the diurnal rhythm, the age-related changes and for the increase after application of hCG.

Age Factors↗
PubMed1978

Relationships between short-term variations of LH, FSH, prolactin and testosterone in peripheral plasma of prepubertal bulls.

In 2 prepubertal bulls 10-min blood samples collected during a 24-h period showed that gonadotrophin and testosterone peaks occurred regularly at intervals of 6h in one animal and 8h in the other. There was a clear relationship between the LH, FSH and testosterone peaks. The increase of gonadotrophin levels was followed 20 +/- 6 (s.d.) min later by an increase of testosterone; the interval between the peak values was 61 +/- 9 (s.d.) min. The pattern of prolactin concentration differed; there were two prolonged elevations rather than regular peaks.

Animals↗