Relation between the reproductive status and somatolactin cell activity in the pituitary of pejerrey, Odontesthes bonariensis (Atheriniformes).

VISSIO, PAULA; ANDREONE, L; PAZ, D; MAGGESE, M. CRISTINA; SOMOZA, GM; STRUSSMANN

JOURNAL OF EXPERIMENTAL ZOOLOGY

WILEY-LISS, DIV JOHN WILEY & SONS INC

Lugar: New York; Año: 2002 vol. 293 p. 492 - 499

0022-104X

The aim of this study was to analyze the relationship between somatolactin (SL) expressing cells and the reproductive status in a multiple spawning fish, the pejerrey Odontesthes bonariensis. Somatolactin cells were identified in adults of both sexes by immunocytochemistry using a heterologous piscine antiserum. The area of the cells that showed immunoreactivity to SL (ir-SL) was compared in specimens with different degrees of reproductive activity as inferred from histological examination of the gonads and calculation of the gonadosomatic index (GSI %). The results showed a significant difference between the area of ir-SL cells of resting/regressing (62.9 7 2.1 mm2) and sexually active/vitellogenic (76.8 7 2.3 mm2) females and a significant positive correlation between the ir-SL cellular area and the GSI % (P o 0.01 in both cases). In males, the correlation between the area of ir-SL cells and the GSI % was not statistically significant. However, in those animals with the highest GSI % values, the ir-SL cells appeared more numerous and showed an increase in the immunostained area when compared to individuals with lower GSI % values. The present morphological observations are in accordance with biochemical data obtained from other species and support the assumption that SL might be involved in the regulation of reproduction in fish.