The sequence of the nucleotides at the alpha-sarcin cleavage site in rat 28 S ribosomal ribonucleic acid

The sequence of the 521 nucleotides at the 3' end of a rat 28 S rRNA gene was determined. The region encompasses the site of cleavage of 28 S rRNA by the cytotoxin alpha-sarcin. The toxin hydrolyzes a phosphodiester bond on the 3' side of a guanine residue 393 nucleotides from the 3' end. The alpha-sarcin domain is composed of a purine-rich sequence of 14 highly conserved nucleotides.     

Release of LH after administration of an analog of synthetic LH-RH in cattle

The $\text{in vivo}$ effect of an analog of LH-RH, (Des-Gly-NH₂¹⁰, Proethylamide⁹)-LH-RH, on LH release, was studied in one bull with azooapermia, and one cow with cystic follicle. The single intravenous injection of 100 μg LH-RH analog caused abrupt and marked increase in serum LH and the high levels of LH were maintained for 3 hours. The highest levels of serum LH were 48 and 114 times as high as the pre-treatment levels in a bull and a cow, respectively. Further studies are being undertaken to evaluate this compound for improving reproductive function in cattle.     

Effects of non-24-hour days on reproductive efficacy and embryonic development in mice

ICR female mice were exposed to either 22 (L11, D11) or 26 hour day (L13, D13) light/dark cycles for at least 2 weeks before mating and/or during pregnancy. The mating rates of these animals decreased considerably. When pregnant females were examined at gestation days 12.0 or 17.5, resorption rates were increased, the embryos weighed less, and development was retarded in the experimental groups with preconceptional exposure to non-24-hour days. We speculate that in mice maternal and paternal pre- and periconceptional environment of daily light/dark cycles is important for normal reproductive efficacy and normal embryonic development during pregnancy.