Fish full life‐cycle testing for the weak estrogen 4‐tert‐pentylphenol on medaka (Oryzias latipes)

Abstract

We studied the chronic effects of 4-tert-pentylphenol (4-PP) on reproductive status of medaka (Oryzias latipes) over two generations under continuous exposure, with the goal of verifying the applicability of the fish full life-cycle test (FFLC) for this weak estrogen with this species. The exposure of parental (F0) medaka to 4-PP was begun on embryos within 12 h after fertilization and continued for up to 101 d, with monitoring of embryological development, hatching, posthatch survival, growth, sexual differentiation, reproduction, and hepatic vitellogenin (VTG) levels under flow-through exposure to 4-PP at mean measured concentrations of 51.1, 100, 224, 402, and 931 microg/L. Eggs (F1) spawned from the F0 fish at 99, 100, and 101 d after hatch also were examined for hatchability, survival after hatching, growth, sexual differentiation, and hepatic VTG levels, until 61 d after hatch. In the FFLC with the F0 medaka, the lowest-observed-effect concentration (LOEC) of 4-PP for lethal and sublethal toxicity (as shown by growth inhibition) was 931 microg/L. The LOECs for estrogenic effects (as shown by abnormal sexual differentiation and VTG induction) were 224 and < or = 51.1 microg/L, respectively, and the LOEC for reproductive impairment was 224 microg/L. Therefore, the effective concentrations of 4-PP for abnormal sexual differentiation and reproductive impairment were about four times lower than those for lethal and sublethal toxicity. In the F1 medaka, the LOECs for sublethal toxicity and estrogenic effects were 224 and < or = 51.1 microg/L, respectively. This finding suggests that the continuous exposure to 4-PP over two generations induced these adverse effects at lower concentrations in the F1 generation than those in the F0 generation. Thus, 4-PP has estrogenic effects that reduce the reproductive potential of medaka. The results indicate that the FFLC with medaka is applicable to the evaluation of weak estrogens.

Exposure of three generations of the estuarine sheepshead minnow (Cyprinodon variegatus) to the androgen, 17β‐trenbolone: Effects on survival, development, and reproduction

“…Exposures of freshwater fish to EDCs that include an entire life cycle have demonstrated increased sensitivity of subsequent generations measured by fecundity and survival of zebrafish [30], and changes of hepatic vitellogenin and incidence of testisova in medaka [11,31,32]. Multiple-generation exposures of sheepshead minnow to Tb in the present study and to 17b-estradiol [4,5] have demonstrated that in some cases, short-term adult exposures may not effectively predict the impacts on continuously exposed populations.…”

Multigenerational exposure of the estuarine sheepshead minnow (Cyprinodon variegatus) to 17β‐estradiol. I. Organism‐level effects over three generations

“…28,2009 accurately determine fish sex. In contrast, GSI and fecundity were unaffected, but fertility was significantly decreased, in female medaka exposed to 4-tert-pentylphenol at 224 mg/L [29]. In general, gross developmental changes in sheepshead minnows, as measured by length and somatic indices, were insensitive and poor indicators of exposure to E2.…”

“…Studies have included tributyltin exposures initiated with sheepshead minnow embryos through 30 dph of F1 fish [26], exposure of adult F0 zebrafish (Danio rerio) through 41 dph of the F1 generation to E2 and tamoxifen [27], and exposure of F0 medaka eggs through F1 maturation to the weak xenoestrogens 4-nonylphenol and 4-tert-pentylphenol [28,29]. Studies have included tributyltin exposures initiated with sheepshead minnow embryos through 30 dph of F1 fish [26], exposure of adult F0 zebrafish (Danio rerio) through 41 dph of the F1 generation to E2 and tamoxifen [27], and exposure of F0 medaka eggs through F1 maturation to the weak xenoestrogens 4-nonylphenol and 4-tert-pentylphenol [28,29].…”

Bisphenol A Incorporated into Eggs from Parent Fish Persists for Several Days

“…As experimental methods to observe long-term effects, partial life cycle and full life cycle tests have been conducted in order to clarify the effects of chemical compounds over several generations. 11,13,14) It is known that the influence of chemical exposure appears more significantly in juveniles and embryos during developmental stages than in mature parents; thus, several methods, such as exposing fry just after hatching 7,8,[15][16][17] and exposing fertilized eggs, 6,10,11,[16][17][18][19][20] as well as microinjection into fertilized eggs, 21,22) are also utilized. In a special case, artificially inseminated eggs were exposed.…”