Rapid effects of insulin on cyclic GMP location in an intact protozoan.

We studied rapid changes in location of cyclic GMP in Tetrahymena pyriformis. Insulin caused cGMP localization in cilia and near the plasma membrane (0.5-1 min). Later (1-5 min) cGMP localization was diffuse in cytoplasm with perinuclear accentuation. Inactive insulin analogs did not elicit these changes.     

Converting enzyme content of different tissues of the rat

Résumé On a dosé l'enzyme de conversion dans différents tissus du rat au moyen d'une méthode chimique mesurant la libération d'histidyl-leucine à partir du substrat synthétique Z-phe-his-leu. Le poumon contient au moins 8 fois plus d'enzyme que tous les autres tissus étudiés. Il en contient notamment plus de 100 fois plus que le foie.     

Substances régulatrices de la croissance végétale

Zusammenfassung Durch Einwirkung von Simazin wird bei Elodea die Photosynthese gehemmt, der Sauerstoffverbrauch durch Atmung erhöht und keine Zerstörung der Zellbestandteile beobachtet. In Gegenwart von Simazin bleiben die Deshydrasesysteme der Zelle aktiv.

---

---

5^e communication (voir les travaux précédents deA. Gast etB. Exer).     

Rnx deficiency results in congenital central hypoventilation

The genes Tlx1 (Hox11), Enx (Hox11L2, Tlx-2) and Rnx (Hox11L2, Tlx-3) constitute a family of orphan homeobox genes. In situ hybridization has revealed considerable overlap in their expression within the nervous system, but Rnx is singularly expressed in the developing dorsal and ventral region of the medulla oblongata. Tlx1-deficient and Enx-deficient mice display phenotypes in tissues where the mutated gene is singularly expressed, resulting in asplenogenesis and hyperganglionic megacolon, respectively. To determine the developmental role of Rnx, we disrupted the locus in mouse embryonic stem (ES) cells. Rnx deficient mice developed to term, but all died within 24 hours after birth from a central respiratory failure. The electromyographic activity of intercostal muscles coupled with the C4 ventral root activity assessed in a medulla-spinal cord preparation revealed a high respiratory rate with short inspiratory duration and frequent apnea. Furthermore, a coordinate pattern existed between the abnormal activity of inspiratory neurons in the ventrolateral medulla and C4 motorneuron output, indicating a central respiratory defect in Rnx mice. Thus, Rnx is critical for the development of the ventral medullary respiratory centre and its deficiency results in a syndrome resembling congenital central hypoventilation.     

Acceleration of the rate limiting step in norepinephrine biosynthesis by potassium

Zusammenfassung Kalium erhöht die Bildung von markiertem Noradrenalin aus markiertem Tyrosin im isolierten Vas deferens. Es wird angenommen, dass dieser Effekt auf eine Steigerung der Tyrosin-Hydroxylase zurückzuführen ist.