G. B. Gerber

Plasma hormone levels in normal and lead-treated pregnant mice

Dietary lead (0.5%) was given to mice which, after mating, exhibited a vaginal plug. Estradiol, progesterone and prostaglandins E and F 2α were determined in, the plasma by radioimmuno assay at different times thereafter. The increase in estradiol and decrease in prostaglandins prior implantation are not greatly altered by lead treatment, whereas the subsequent increase in progesterone and later in estradiol is abolished. It is concluded that the lower number of pregnancies seen in lead-treated mothers is due to a maternal hormonal imbalance caused by lead.

Embryonic death in mouse due to lead exposure.

Female mice which displayed a vaginal plug after mating were given a diet containing 0, 0.125, 0.250, 0.500% of lead as lead acetate and were dissected 16 to 18 days later. Lead treatment was found to reduce significantly the incidence of pregnancies and to increase the postimplantation loss in the pregnant females.

Increased ALA dehydratase activity and spleen weight in lead-intoxicated rats. A consequence of increased blood cell destruction.

Lead was given in the diet (1%) to rats from birth and at different times the animals were studied for delta amino levulinic acid dehydratase (ALAD) activity, spleen weight,59Fe incorporation in erythrocytes and51Cr-labeled erythrocytes survival. The increased ALAD and spleen weight found after lead treatment is explained as a consequence of a shortened survival, which results in a younger age of circulating erythrocytes with higher ALAD activity.

Studies on Detoxication in the Isolated Perfused Liver

SummaryConjugation and excretion of bile acids and metabolism of taurine 35S were studied in the isolated perfused liver from normal and x-irradiated rats. More bile acids are present and more were synthesized after irradiation. Taurine was removed more rapidly by the irradiated liver if no bile acids were added. No difference existed between normal and irradiated liver with respect to conversion of deoxycholate to cholate, conjugation of bile acids and the general excretion pattern of bile steroids and phospholipids.

Nucleoside aminohydrolase, an enzyme involved in the degradation of deoxycytidine

Hohe Nukleosidaminohydrolase-Aktivitäten finden sich in Niere, Leber und Darm von Hamstern. Bei Mäusen hängt die Aktivität vom Tierstamm ab und steht in Beziehung zur Deoxycytidinausscheidung.

Synthesis of NAD and catabolism of nicotinic acid in the isolated perfused liver of normal and X-irradiated rat.

SummaryThe synthesis of NAD and the formation of catabolites from nicotinic acid 14C was studied in isolated perfused liver from normal and x-irradiated rats. Large amounts of nicotinic acid and nicotinamide increase NAD content of perfused liver as they do in vivo. Synthesis of NAD is slightly diminished after irradiation, particularly under loading conditions whereas its catabolism is enhanced. Data for the rates of reactions are given for different pathways involved in NAD metabolism.

Renin-angiotensin and Aldosterone in the Gastro-intestinal Syndrome after Whole-body Irradiation

;but our earlier data (Gits and Gerber 1973) indicate that sodium loss per se is not sufficient to explain the rapid death after comparable short periods of diarrhoea. Changes in vascular-extravascular space, in renal excretion, in bloodflow and blood-pressure precede by several hours the onset of diarrhoea (Gerber and Watters 1974, Watters and Gerber, unpublished data). Of the various factors in the gastro-intestinal syndrome, we have now studied the changes in renin and aldosterone intervening after supra-lethal and sub-lethal whole-body irradiation .

Fate of DNA-labelled bone-marrow cells from different mouse strains injected into syngeneic irradiated recipients

Knochenmarkszellen, durch Injektion von3H-Thymidin in syngenischen Spendern markiert, wurden in bestrahlte Empfänger von AKR-, C57 Bloder BALB/c-Mäuse injiziert, wobei grösste Aktivität in der Milz, dann im Knochenmark und im Thymus gefunden wurde. Aktivitätsverlust war während der 6tägigen Beobachtungsperiode in Milz und Knochenmark am stärksten. Auch die Regeneration und die Veränderungen der spezifischen Aktivität der DNA dieser Organe waren bei C 57 Bl- und BALB/c-Mäusen am ausgeprägtesten. Die markierten Spenderzellen im Thymus scheinen nicht von Zellen zu stammen, die über das Knochenmark dorthin transportiert wurden, sondern wurden unmittelbar vom Thymus aufgenommen.

STUDIES ON DETOXICATION BY THE PERFUSED LIVER. II. BILIRUBIN CONJUGATION AND EXCRETION AFTER IRRADIATION

SummaryFormation of conjugated bilirubin and its excretion into the bile has been studied in the isolated perfused liver of normal and x-irradiated rats. Bilirubin is removed rapidly from the blood and is excreted, after a lag-period, to about 70–85 per cent as conjugated bilirubin into the bile. Conjugation occurs mainly with glucuronic acid but also with other compounds.Removal of bilirubin from the blood and excretion of conjugated bilirubin in the bile are delayed in the perfused liver of x-irradiated rats.

Metabolism of NAD after whole-body irradiation. IV. Incorporation of nicotinamide by isolated perfused liver and by intact rats.

SummaryThe metabolism of nicotinamide was investigated in organs of normal and x-irradiated intact rats (24 h after 1000 R whole-body irradiation) and in isolated perfused rat liver. Rates of reactions were calculated from the data on liver perfusion. At low substrate levels, incorporation of nicotinamide seems to involve pathways via nicotinamide mononucleotide, whereas at high substrate levels the Preiss-Handler pathway via nicotinic acid may play a role. The changes after irradiation are explained as the result of an increased catabolism of NAD which cannot be entirely compensated for by re-synthesis.