The effects of polychlorinated biphenyls on plasma steroid levels and hepatic microsomal enzymes in fish

Abstract

Aroclor 1254 was administered intraperitoneally (25 mg kg body wt-I in 1 ml of arachis oil) at weekly intervals for 4 weeks to trout and carp; arachis oil was used as the control. Activities of the following hepatic microsomal enzymes, aminopyrine demethylase, pnitroreductase, UDP-glucuronyl-transferase and I-leucyl-P-naphthylamide splitting enzyme were measured in both species; cytochrome P460 and microsomal protein contents were also determined.The changes in the levels of androgens, oestrogens and corticoid hormones were measured in the circulating blood of control and treated groups at weekly intervals. The blood was obtained by cardiac puncture.Results indicated (a) a significant increase in the activities of all the enzymes measured except 1-leucyl-P-naphthylamide splitting enzyme, (b) cytochrome P450 and microsomal protein contents were increased in trout, but not in carp, (c) a significant reduction in the plasma levels of androgens, oestrogens and corticoids in the treated groups, particularly at the end of the fourth week and (d) there was a correlation between increased enzyme activities and a decrease in plasma hormone levels.

Polychlorinated biphenyls, mercury, and potential endocrine disruption in fish from the Hudson River, New York, USA

“…Median concentrations of E2 in male and female carp were inversely correlated with sediment PCB residues in Woods Pond, Massachusetts (Smith et al, 2002). Antiandrogenic and PCBs, HG, and endocrine disruption in Hudson fish antiestrogenic effects were observed in carp after four weeks of intraperitoneal injections of Aroclor 1254; concentrations of estrogens and androgens in blood of female and male were significantly reduced (Sivarajah et al, 1978a); developing oocytes became fragmented and spermatozoa were damaged (Sivarajah et al, 1978b).…”

Development of a sediment bioassay to determine bioavailability of PAHs to fish

“…These changes in reproductive steroid hormones have not been directly linked to MFO induction, but seem to be related to multiple breaks in the hypothalamo-pituitary-gonadal axis controlling reproduction . Despite the inability to directly correlate MFO induction with steroid depression (Munkittrick et al, 1994a), additional recent work has shown that depressions in steroid hormone production or reproductive performance can occur after exposure to a variety of other compounds associated with MFO induction, including some pesticides (Munkittrick et al, 1994b), PCBs (Freeman & Idler, 1975;Sivarajah et al, 1978;Thomas, 1988Thomas, , 1990Greeley et al, 1993;Kidd et al, 1993) and PAHs (Truscott et al, 1983;Thomas, 1988Thomas, , 1990McMaster et al, 1995b).…”

The biliary accumulation of corticosteroids in rainbow trout,Oncorhynchus mykiss, during acute and chronic stress

“…We have observed this biphasic cortisol response to chronic stress previously (Pottinger, Prunet and Pickering, unpublished) but had ascribed the phenomenon to interrenal exhaustion. In trout and carp subject to treatment with an organic compound, Aroclor 1254, UDP-glucuronyltransferase (UDPGT) levels increased, and concomitant with the increased activity of the conjugating enzymes a decrease in plasma steroid levels, including corticosteroids, was noted (Sivarajah et al 1978). Similarly, increased accumulation of [ 3 H]estradiol was observed in the bile of rainbow trout in which UDPGT levels had been elevated by treatment with -naphthoflavone (Forlin and Haux 1985).…”