A redox system for brain targeted estrogen delivery causes chronic body weight decrease in rats

The effects of 2 redox based carriers for brain directed delivery of estradiol (CDS-E2) and ethinyl estradiol (CDS-EE) on body weight were examined in rats. A single dose of CDS-E2 (3 mg/kg) decreased weight gain in castrate rats for at least 24 days. The dose response of weight gain and LH suppression were compared 12 days and 12 to 25 after CDS-E2 and CDS-EE, respectively, in ovariectomized (OVX) rats. Weight decrease was detected at a lower dose and was significant for longer after drug treatment than LH decrease. Both compounds were more potent than equimolar estradiol or estradiol valerate in reducing weight gain. Intact rats also showed decreased weight gain but were less sensitive to CDS-E2 compared to OVX rats. The effects appeared to be estrogen specific as carrier-linked testosterone had no effect on weight. The mechanisms of sustained and potent drug effects on weight are being explored.     

Phenotypic variation in susceptibility of honey bees,Apis mellifera,to infestation by tracheal mites,Acarapis woodi

A laboratory bioassay was used to study phenotypic differences in susceptibility of honey bees,Apis mellifera L., to tracheal mites,Acarapis woodi Rennie. Significantly different infestation frequencies were found in bees from 23 colonies containing queens that were instrumentally inseminated with single drones. Queens and drones originated from a closed population composed of commercial stock from various areas of the United States.Mites were randomly distributed with respect to right and left prothoracic tracheae. Tracheae containing mites were no more or less attractive to migrating mites than non-infested tracheae. The same quantity of progeny per female was produced in tracheae containing 1–3 mites. Female mites apparently do not migrate a second time after egg laying begins.The degree of phenotypic variation suggests that selection of honey bees for tracheal mite resistance is feasible.