“Aims: Postpartum blues is thought to be related to hormonal events accompanying delivery. We investigated whether blues-like symptoms depend on the rate of the decline of hormones, by comparing the behavioral consequences of an abrupt versus a gradual decline of gonadal hormones in an animal model.\n\nMethods: Female rats were treated with estrogen and progesterone for 23 days, administered either by injections or by subcutaneously implanted tubes filled
with hormones. A gradual hormone GS-9973 decline was achieved by discontinuation of the injections: and rapid decline by removal of the tubes. Control groups received either a continued treatment or no hormones. In the period following the decline the stress-reactivity was tested with an acoustic startle test on 3 consecutive days, and anxiety behavior with an open-field test on the 2nd day. Selleck Screening Library The Hypothalamus-, Pituitary-, Adrenal-axis (HPA-axis) response to stress was measured by assessing the corticosterone levels and hypothalamic c-fos expression stress-response at the 4th day.\n\nKey findings: The rapid decline of hormones induced an increased startle response
lasting for two days, and increased anxiety-like behavior in the open field. This was not found in the gradual-decline and control groups. The HPA-axis response to stress was decreased in all hormone-treated animals.\n\nSignificance: This animal Study suggests that: 1) abrupt rather than gradual hormonal changes induce increased stress-reactivity and anxiety-like behavior: 2) postpartum blues may result from
differences in the capacity to adapt to the changes of gonadal hormones; 3) Recovery of pregnancy-induced diminished HPA-axis response is independent of the postpartum hormone kinetics. (C) 2008 Elsevier Inc. All rights reserved.”
“Rhynchophorus ferrugineus (Coleoptera, PFTα nmr Curculionidae) is the most threatening pest of palms worldwide. The potential of gamma-irradiated males to spread a pathogenic strain of the entomopathogenic fungus Beauveria bassiana (Ascomycota: Clavicipitaceae) to control this pest was studied. First, the effects of gamma irradiation (15 and 25 Gy) on the mating success and performance of adult males irradiated at age one day were studied in the laboratory. Although male longevity decreased after irradiation (118.6 vs. 244.7 days for irradiated and control males, respectively) and their testes suffered from the treatment, fecundity of mated females did not depend on the irradiation status of the male (86.8 +/- 5.5 eggs in 15 days).