THE DYNAMICS OF VITELLOGENIN SEQUESTRATION INTO VITELLOGENIC OVARIAN FOLLICLES OF THE RAINBOW-TROUT, SALMO-GAIRDNERI

This study provides quantitative data on the dynamics of protein sequestration into vitellogenic follicles of the rainbow trout, Salmo gairdneri. The ovarian uptake of both radiolabelled vitellogenin (VTG) and bovine serum albumin (BSA) were investigated in a homogenous population of maturing vitellogenic females. Ten fish were injected with 3H. VTG directly into the bloodstream. Concomitantly, five of these fish received an equal amount of 14C.BSA. Twenty two hours after injection, of the tissues sampled, the greatest proportions of 3H. VTG were present in the blood (into which the radio labels were administered) and in the ovary (up to 28% and 46% of that originally present in the blood, respectively). VTG uptake was both selective, rates of uptake far exceeding that of the 14C.BSA, and rapid. 3H. VTG was sequestered at rates of between 35 to 390 ng.mm2 follicle surface-1.h-1 in the different fish. The rates of VTG uptake into similarly sized follicles varied both between different sites within the ovary (by up to 30%) and also between the ovaries (by up to 38%) of an individual fish. © 1990 Kugler Publications.