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Cell Biology International (2001) 25, 885–892 (Printed in Great Britain)
THYROID-STIMULATING HORMONE AND GROWTH HORMONE RELEASE ALTERATIONS INDUCED BY MOSQUITO LARVAE PROTEINS ON PITUITARY CELLS
Federico Bolognaniab, Rodolfo Gustavo Goyaab and Jorge Rafael Ronderosa,f1
aCátedra de Histologia y Embriologı́a ‘B’, FCM—Cátedra de Histologia y Embriologia Animal, FCNyM—Universidad Nacional de La Plata, Calle 60 y 120 (1900), La Plata, Argentina
bINIBIOLP, UNLP-CONICET, Calle 60 y 120 (1900), La Plata, Argentina


Abstract

Mosquito larvae crude extract has shown to modulate cell proliferation of different mouse epithelial as well as human mononuclear cell populations in vivo and in vitro. A soluble fraction of the extract, with a molecular weight ranging from 12 to 80kD, also showed an inhibitory effect on the proliferation of mouse hepatocytes. This effect disappeared after heating the extract at 90°C for 60min, suggesting that some proteinaceous molecule is involved. We report the effect of dialysed extract (MW >12kD) on the concentration of both thyroid-stimulating hormone (TSH) and growth hormone (GH) in an incubation medium of pituitary cells from normal and oestrogenised rats. Time- and dose-dependent response of both hormones resulted in increasing TSH levels. Concentrations of GH were lower in the treated than in control pituitary cells. The time elapsed until the finding of differences suggests the presence in the mosquito extract of some protein binding the hormone. The differences were not due to lethal toxic effects since the Trypan blue viability test showed no differences between control and treated cells. Furthermore, the effect disappeared when the extract had previously been heated at 90°C for 60min. Finally, our results suggest the presence of some proteins in the mosquito Culex pipiens L. larvae, which would act as a pituitary hormone regulator.


Key words: insect, mosquito, growth factors, pituitary, thyroid stimulating hormone (TSH), growth hormone (GH).

f1To whom all correspondence should be addressed: Dr Jorge R. Ronderos, Cátedra de Histologı́a y Embriologı́a ‘B’, Fac. de Cs. Médicas-Universidad Nacional de La Plata, Calle 60 y 120 (1900) La Plata, Argentina. Fax: 054-0221-4258988; E-mail:jrondero@museo. fcnym.unlp.edu.ar


Received 11 July 2000; accepted 5 January 2001

doi:10.1006/cbir.2001.0716


ISSN Print: 1065-6995
ISSN Electronic: 1095-8355
Published by Portland Press Limited on behalf of the International Federation for Cell Biology (IFCB)