Plasma levels of androstenedione, epitestosterone, testosterone and oestrogens in cows at parturition.

The concentration of total unconjugated oestrogens in the peripheral plasma of cows increased from 2.00 +/- 0.20 (S.E.M.) ng/ml 7 days before to 3.87 +/- 0.50 ng/ml 1 day before parturition and declined to values below 0.30 ng/ml on day 2 post partum. The concentrations of androstenedione, epitestosterone and testosterone remained approximately constant at 0.90 +/- 0.10, 0.92 +/- 0.08 and 0.40 +/- 0.20 ng/ml respectively during the last week of pregnancy. After parturition the concentration of the three androgens declined rapidly. Similar to data obtained in goats we did not find a marked increase in androgen levels in the peripheral blood of cows before parturition.

[Specific incorporation of labelled tissue homogenates into the homologous organs of the rat (author's transl)]. / Spezifische Einlagerung markierter Gewebshomogenate in die homologen Organe der Ratte

The time course of the incorporation of radioactivity into the liver, kidney, heart, spleen, lung, adrenal glands, and testes following subcutaneous application of L-histidine-2,5-T-labelled homogenates of liver, kidney and heart has been measured in 105 male Sprague-Dawley rats aged 3 months (weight: x = 350 g). The homogenates had been prepared from organs of rats of the same age, sex and weight, each labelled with 400 muCi L-histidine-2,5-T. The maximal incorporation of activity from the homogenates into the organs investigated has been found 24 h after injection. In the kidney, however, an additional peak appeared already 5 h post applicationen. The comparison of the activities of the liver, kidney and heart, taking into account the differences in organ metabolism, revealed a significantly higher incorporation into the homologous than in the non-homologous organs. This specific incorporation appeared 2 h after the injection and could be found until about 24 h. The type of labelling, the method of sample preparation and the time of absorption allowed to conclude that the specific affinity to the homologous organs might have been due to a relatively small amount of short peptides. The functional significance especially for the regeneration of impaired organs has been discussed taking into account earlier results.