Structure and expression of a human oxytocin receptor.

Just before the onset of labour, uterine myometrium becomes extremely sensitive to oxytocin, for which it is a primary target tissue, because of a dramatic increase in the number of oxytocin receptors. We report here the structure and expression of the human oxytocin receptor complementary DNA isolated by expression cloning. The encoded receptor is a 388-amino-acid polypeptide with 7 transmembrane domains typical of G protein-coupled receptors. The oxytocin receptor, expressed in Xenopus oocytes, specifically responds to oxytocin and induces an inward membrane current. Messenger RNAs for the receptor are of two sizes, 3.6 kilobases in breast, and 4.4 kilobases in ovary, uterine endometrium and myometrium. The mRNA level in the myometrium is very high at term. We conclude that the increase in receptor number in the myometrium at labour is, at least in part, due to the increase in mRNA.     

The joining of V and J gene segments creates antibody diversity

The variable regions of mouse kappa (kappa) chains are coded for by multiple variable (V) gene segments and multiple joining (J) gene segments. The V kappa gene segments code for residues 1 to 95; the J kappa gene segments code for residues 96 to 108 (refs 1-3). This gene organisation is similar to that encoding the V lambda regions. Diversity in V kappa regions arises from several sources: (1) there are multiple germ-line V kappa gene segments and J kappa gene segments; (2) combinatorial joining of V kappa gene segments with different germline J kappa gene segments; and possibly, (3) somatic point mutation, as postulated for V lambda gene segments. Also, from a comparison of the number of germ-line J kappa gene segments and amino acid sequences, it has been suggested that J kappa region sequences may be determined by the way V kappa and J kappa gene segments are joined. This report supports this model by directly associating various J kappa sequences with given J kappa gene segments.     

Follicles development in the foetal human ovary.

In the foetal human ovary, diameters of oocyte and follicle, as well as those of oocyte and nucleus, are found to be positively and linearly correlated with each other. Follicle diameter and number of granulosa cells also show a positive and linear relationship. Finally, in all ovaries examined, from 5 months after conception onwards, small antral follicles were assessed.     

Effects ofs-triazines on protein synthesis in leaves of peas (Pisum sativum L.) and sweet corn (Zea mays L.) and on the ultrastructure of pea cotyledons

Zusammenfassung Nachweis, dass die Blattbehandlung mit subletaler Konzentration von Simazin, Propazin, Igran und Prometon die Protein-Synthese bei Erbse und Mais vermehrt. Die Blattbehandlung mit Simazin zerstörte die Ultrastruktur des Samenlappens bei der Erbse.

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This study was supported by the Agriculture Research Service, USDA, Grant No. 12-14-100-9903, administered by the Human Nutrition Division, Beltsville, Maryland.