STP1364

    Pesticide Effects on Prolactin Release from the Rostral Pars Distalis In Vitro and Their Effects on Growth In Vivo in the Tilapia (Oreochromis mossambicus)

    Published: Jan 1999


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    Abstract

    Prolactin release from prolactin-cell-containing tissue, the rostral pars distalis (RPD) of the tilapia pituitary, is sensitive to estrogens. This study was undertaken to evaluate the effect of two estrogenic pesticides, p,p'-DDT and o,p'-DDD, on the release of both tilapia prolactins (PRL177 and PRL188) from the RPD in static incubation, and to examine the effect of exposing tilapia fry to o,p' -DDD on growth and development. We found thatp,p' -DDT stimulated the release of both PRL177 and PRL188, and that o,p'-DDD inhibited the release of PRL188 at the concentrations employed. We also found that 8 months after exposing fry to o,p'-DDD for 28 days, the body weight and liver weight of males and females were significantly different from those of untreated control animals (P<0.01). Gonad weight and pituitary weight were not affected. We also found that 8 months after exposing fry to the estrogen ethynylestradiol (EE2), the body weight of males was significantly lower (P<0.01) and the body weight of females was significantly higher (P<0.01) than that of the respective untreated controls. Treatment with EE2 also significantly lowered (P<0.05) the liver weight of males and significantly increased (P<0.01) the gonad and pituitary weights of females compared with their respective controls. The lowest dose of o,p' -DDD used in the in vivo study induced a significant increase in the number of males, an effect opposite to that of EE2.

    Keywords:

    tilapia, prolactin, p,p, '-DDT, o,p, '-DDD, ethynylestradiol, growth, development, bioassay, Oreochromis mossambicus


    Author Information:

    Meredith, HO
    Graduate Research Assistant, University of Hawaii, Honolulu, HI

    Richman, NH
    Junior Researcher, Laboratory Assistant and Research Associate, Hawaii Institute of Marine Biology, University of Hawaii, Honolulu, HI

    Collier, JT
    Graduate Research Assistant, University of Hawaii, Honolulu, HI

    Seale, AP
    Graduate Research Assistant, University of Hawaii, Honolulu, HI

    Riley, LG
    Graduate Research Assistant, University of Hawaii, Honolulu, HI

    Ball, CH
    Junior Researcher, Laboratory Assistant and Research Associate, Hawaii Institute of Marine Biology, University of Hawaii, Honolulu, HI

    Shimoda, SK
    Junior Researcher, Laboratory Assistant and Research Associate, Hawaii Institute of Marine Biology, University of Hawaii, Honolulu, HI

    Stetson, MH
    Professor, University of Delaware, Newark, DE

    Grau, EG
    Professor, University of Hawaii, Honolulu, HI


    Paper ID: STP15806S

    Committee/Subcommittee: E47.04

    DOI: 10.1520/STP15806S


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