Concentrations of adrenal corticoids in plasma were determined by a competitive protein-binding technique using jugular blood samples taken three times daily and more frequently during labor from 21 cows before and after parturition. The prepartum value was 6 ng/ml with a sharp rise during the last 16 h before calving. The average value at the time of calving was 19.2 ng/ml with a significant drop 1 h after calving to 11.2 ng/ml and a return to basal concentrations by 3 days postpartum. Evidence that labor is responsible for the increased corticoid is given. Maternal cortisol at calving was correlated with the time taken to calve .23, calf cortisol .04, cow:calf weight ratio -.07, and calf weight .14.

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A repetitive element in C.elegans has been found that bears high homology to the element mariner of Drosophila mauritiana (EMBL accession number X77804). This element is present in about 20 copies in the N2 strain of C.elegans, and appears in roughly equal copy numbers in the related strain BO and in the hybrid strains RW7097 and TR679. There is only one copy of this MLE in three related species of Caenorhabditis. A cDNA of this mariner-like element (MLE) codes for a protein with 58% homology to the Drosophila transposase. The mariner-like element is not mobile in N2. This class of elements has now been described in insects, planaria and nematodes (GenBank accession number M98552 and this report).

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