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PARENT SESSION

PT03 Persistent Organic Pollutants (POPs)
Exhibit Hall
8:00 AM - Tuesday

(PT011) Cytochrome P4501A1 (CYP1A1) expression in bottlenose dolphins (Tursiops truncatus) from the Northwest Atlantic: evidence for integument stratification.

Montie, E1, 2, Fair, P3, Bossart, G4, Hohn, A5, Mitchum, G3, McFee, W3, Moore, M1, Hahn, M1, 1 Woods Hole Oceanographic Institution, Woods Hole, MA, USA2 Massachusetts Institute of Technology, Cambridge, MA, USA3 NOAA, National Ocean Service, Charleston, SC, USA4 Harbor Branch Oceanographic Institution, Ft. Pierce, FL, USA5 NOAA, National Marine Fisheries Service, Beaufort, NC, USA

ABSTRACT- Biochemical and histological evidence suggests that blubber is stratified in cetaceans. Halogenated aromatic hydrocarbons (HAHs) bioaccumulate in blubber to a greater degree than in other tissues. Therefore, it is important to understand the structure and dynamics of blubber layers and how these characteristics affect the dynamics of HAHs and subsequent biochemical responses. Of particular interest is the response of cytochrome P4501A1 (CYP1A1) to planar HAHs (e.g. non-ortho and mono-ortho PCBs) in the blubber. We used established histological and immunohistochemical methods to understand the structure of blubber and to assess the expression of CYP1A1 in skin-blubber biopsies of bottlenose dolphins (Tursiops truncatus) captured in the waters of Cape May, NJ (n=4), Charleston, SC (n=38), and Indian River Lagoon, FL (n=36). Histological analysis of blubber revealed stratification of the blubber into three layers: a superficial layer (very high density of structural fibers and few adipocytes), a middle layer (more and larger adipocytes, and fewer structural fibers), and a deep layer (increased structural fiber densities and smaller adipocytes). Preliminary histological analysis also revealed differences in structural fiber densities, adipocyte numbers, and adipocyte sizes among dolphins sampled at the three sites; NJ dolphins have more and larger adipocytes and lower densities of structural fibers than CHS and IRL dolphins. CYP1A1 expression was strongest and most frequent in capillary endothelial cells within the blubber. CYP1A1 expression in integument (skin and underlying blubber) was greater in Charleston versus Indian River Lagoon and Cape May bottlenose dolphins. CYP1A1 expression differed among the blubber layers: deep blubber layer > middle blubber layer > superficial blubber layer. It is hypothesized that during blubber lipid mobilization, planar HAHs associated with lipid in adipocytes from the deep and middle blubber layers may be transported into the circulatory system, possibly inducing CYP1A1 in vascular endothelial cells. [Supported by NOAA]

Key words: cytochrome p4501a1, bottlenose dolphin, tursiops truncatus, blubber


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