Vitamin D and reproduction in Wistar rats]

Females have received from weaning a semi-synthetic diet (0,35% Ca; 0,32% P; 0,03% Mg), with or without vitamin D (+/- D). Fertility of these females was not changed. At weaning, the young from mothers--D had lower weight, calcemia and phosphatemia, but the ash content of the femur was the same as for young from mothers + D. Young rats from mothers +/- D were given the diet with or without vitamin D. 19 days after weaning, the diet of the mother (+/- D) appears to be the principal factor for growth, calcemia and the ash content of the femur; the diet of the young (+/- D) produced only slight differences between ash contents.     

Vitamin A consumption in pregnant and non pregnant rats, and in castrated rats receiving or not receiving estradiol or pregnenolone; relation to tocopherol and cytochrome P-450]

Consumption of vitamin A and cytochrome P 450 by pregnant Rat is more important than in non pregnant and ovariectomised Rat. Estradiol implant in ovariectomised female has some, but slighter, influence only on retinol. These physiological situations have no action on the hepatic levels of tocopherols (total and alpha). These results are discussed.     

Possible influence of prolactin on intestinal hypertrophy in pregnant and lactating rats

Summary The increase in intestinal weights during lactation, and to a lesser extent during pregnancy, is inhibited by bromocriptin. This suggests that increased prolactin secretion might be responsible for gut hypertrophy during lactation.This work was supported by N.I.H. grant Ca-05388 and a Rockefeller Foundation Fellowship.The author is very grateful to Professor H.A. Bern for his useful suggestions. Professor E. Flückiger, Sandoz Ltd, kindly supplied the bromocriptin used in this study.     

Vitamin D,example and challenge

Zusammenfassung Vitamin D ist eine in verschiedener Hinsicht interessante Verbindung, deren Untersuchung zu neuen Erkenntnissen auf dem Gebiete der Stereochemie, der Photochemie und der Reaktionsspezifität beigetragen hat. Insbesondere die damals intrigierende Entstehungsweise unter dem Einfluss von Ultraviolettstrahlung (antirachitische Wirkung des Sonnenlichtes) hat frühzeitig die Aufmerksamkeit von Chemikern und Physikern erregt. Es sind dann die sehr spezifisch verlaufenden thermischen und photochemischen Isomerisierungen gewesen, die zum Verständnis des Reaktionsmechanismus und zu den dem Reaktionsverlauf zu grunde liegenden Gesetzmässigkeiten geführt haben. Auch bieten die Moleküle der unterschiedlichen Vitamin-D-Isomeren mit deren Chiralitätszentren und dem polyzyklischen Aufbau nach wie vor ein fruchtbares Gebiet zur Prüfung der Reichweite der modernen Konformationsanalyse und von chiroptischen Betrachtungen.Es wird eine Übersicht über die verschiedenen experimentellen Ergebnisse und die daraus entwickelten theoretischen Spekulationen gegeben. Als Grundlage wird immer wieder die genaue Kenntnis der molekularen Geometrie und der Bindungsverhältnisse angestrebt. Diese lässt sich heutzutage mittels Konformationsanalyse, Valence Force Field-Kalkulationen und insbesondere auch Röntgenanalyse in konsistenter Weise gewinnen. Bei der weiteren Diskussion der (photo)chemischen Prozesse zeigen sich 3 Faktoren zum Verständnis und zur Voraussicht des Ablaufs wichtig. Es ist die schon längst bekannte sterische Hinderung und zwei weitere, beim Studium der Reaktionen im Vitamin-D-Gebiet zuerst formulierte Faktoren: der Einfluss der Orbitalsymmetrie und (für Photoreaktionen) die Lage des Konformationsgleichgewichtes im Grundzustand. Insbesondere das letztgenannte Prinzip hat sich bei der Auffindung von bisher unbekannten Photoprodukten des Vitamins D als sehr wichtig erwiesen.Auch in der Zukunft werden die von der Natur sorgfältig selektionierten Moleküle von Vitamin D und dessen Isomeren ein anregendes Beispiel und Untersuchungsobjekt beim Studium der detaillierten Mechanismen von Photoisomerisierungen und bei der Konformationsanalyse von Molekülen in aktiviertem Zustand darbieten.

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14th Paul Karrer Lecture, presented 20 June 1973, in the Aula of the University of Zurich.     

Effect of hypophysectomy or hysterectomy on the luteal 20α-hydroxysteroid dehydrogenase in pregnant rats

Riassunto Sono stati studiati con metodi enzimoistochimici alcuni meccanismi che controllano la comparsa della 20-idrossi-steroide-deidrogenasi (20-HSD) in ratte gravide o pseudogravide dopo ipofisectomia o isterectomia. I risultati dimostrano che nel primo periodo della gravidanza e in pseudogravidanza, l'ipofisi è necessaria per mantenere i corpi lutei privi di attività 20-HSD.     

Effect of cortisone or triiodothyronine administration to pregnant rats on lysosomal hydrolases in fetal forebrain and cerebellum

Triiodothyronine injected daily to pregnant rats for the last week of gestation (50 microgram/100 g b.wt) increased the specific activities of 5 acid glycosidases in the fetal forebrain and cerebellum. Cortisone (50 mg/100 g b.wt) administered in the same period had no effect on cerebellum acid hydrolases, but decreased their activity in the forebrain.     

Effect of cortisone or triiodothyronine administration to pregnant rats on lysosomal hydrolases in fetal forebrain and cerebellum

Summary Triiodothyronine injected daily to pregnant rats for the last week of gestation (50 g/100 g b.wt) increased the specific activities of 5 acid glycosidases in the fetal forebrain and cerebellum. Cortisone (50 mg/100 g b.wt) administered in the same period had no effect on cerebellum acid hydrolases, but decreased their activity in the forebrain.Supported by grant No. HD 08536 from the National Institutes of Health, Bethesda, Maryland.     

Reduction of isoprenaline induced tachycardia in pregnant rats. Role of a serum factor]

The in vivo isoprenaline (50 microgram/kg) induced tachycardia (beta 1 adrenergic stimulant effect) was decreased in pregnant (20th day) Rats compared to non pregnant Rats. The in vitro positive chronotropic effect of isoprenaline (10 ng/ml) on cultured Rat heart cells was abolished by pregnant Rat serum whereas progesterone (0.10 to 5 microgram/ml) or oestradiol (0.1 to 25 microgram/ml) were ineffective. The decreased beta 1 adrenergic responsiveness in pregnant Rats could be related to a seric factor, different from these two hormones.     

Tissue distribution and nucleic acid binding of chlorambuci-3H in tumor-bearing rats

Summary In tumour and normal rat tissues prolonged alkylation of DNA and RNA by chlorambucil-³H occurs over periods of 24 h. It is suggested that this may indicate the slow release of an alkylating moiety from an intracellular drugmacromolecule complex.     

Vitamin A-deficiency and cartilage in healing skull fractures of rats

Zusammenfassung Die Heilungsvorgänge bei experimentell erzeugten Defekten der Parietalknochen junger Ratten wurden untersucht: Knorpel entwickelt sich im Kallus nach 9-28 Tagen bei Tieren mit einem Vitamin-A-Defizit, jedoch nur in einem von 19 Kontrolltieren, welche Vitamin A zusätzlich erhalten haben.     

Asymmetric distribution of male and female foetuses in the pregnant rabbit uterus

Summary The sex distribution of foetuses in the uterine horn of the pregnant rabbit was found to be asymmetrical, with more males being present in the left uterine horn and more females in the right (p<0.05).     

The role of maternal parathyroids and vitamin D3 metabolites in fetal growth and the deposition of glycogen reserves in the maternal and fetal liver in rats]

Thyro-parathyroidectomy of pregnant Rats at 12.5 days of gestation decreased maternal liver glycogen on 21.5 days of gestation and fetal weight as well as fetal liver glycogen stores. The graft of one parathyroid gland or the injection of 1 alpha-hydroxycholecalciferol in these thyro-parathyroidectomized mothers increased their liver glycogen stores at 21.5 days of gestation. These treatments also markedly increased both fetal weight and fetal liver glycogen stores. It was concluded that maternal 1,25-dihydorxycholecalciferol, which is synthesized under the control of parathyroid hormone secretion, controls fetal growth and liver glycogen stores. The mechanism of these effects (direct or indirect) requires further investigations.     

Demonstration and evolution of chorionic gonadotropin in ewes]

Occurrence of ovine Chorionic Gonadotropin (oCG) is demonstrated in placenta and amniotic fluid with the use of a radioreceptor assay (corpus luteum membranes) in ewes. Identification of oCG is possible as early as 15th day of pregnancy. It should be secreted at a constant rate, and its maximum concentration is recorded on the 130th day. This hormonal factor might be one of the major components accountable for high progesteronemia observed during the 100 last days of pregnancy.     

Activation of the pituitary-adrenal axis by nipple suction in the lactating rat]

The response of the pituitary-adrenal axis to suckling in lactating Rats is dependent on two factors: 1. a psychic factor, which is identical by its effects to the psychological stress of the strange environment (transitory increase of plasma corticosterone and no significant modification of the content of ACTH in the two lobes of the pituitary); 2. a specific factor namely the stimulation of the nipples, which is distinguishable from the psychic factor by a longer release of corticosterone by the adrenals and a durable and significant decrease of the content of ACTH in the pars distalis.     

Placental and fetal contraindications of dexamethasone administration to pregnant rats

Summary Dexamethasone (DEXA) given to pregnant rats for either the last 3 or 6 days of gestation lowered placental, fetal body and adrenal weights. Histologically, DEXA-treated placentas appeared smaller than controls and showed signs of necrosis and pyknosis. Treated animals that were permitted to carry their litters to term did not deliver naturally, and most of their fetuses were dead when excised 1 day postmaturely.