Altered steroid metabolism in several teleost species exposed to endocrine disrupting substances in refuse dump leachate

Endocrine disruption associated with reproductive failure has been reported previously in female perch (Perca fluviatilis) and roach (Rutilus rutilus) from Lake Molnbyggen in Sweden and in female brook trout (Salvelinus fontinalis) from Vadbäcken, a stream emptying into Molnbyggen. Both Molnbyggen and Vadbäcken have been contaminated by toxic leachate from a municipal refuse dump. In this study, female perch were caught in Molnbyggen and the reference lake, Lake Djursjön, to further investigate the endocrine mechanism behind the significant numbers of sexually immature (SIM) female perch in Molnbyggen. Blood plasma analysis of progesterone (P), 17alpha-hydroxyprogesterone (17alpha-OHP), testosterone (T), and 17beta-oestradiol (E2), as well as analysis of brain aromatase activity (P450arom), were carried out. The exceptional high numbers of SIM female perch in Molnbyggen was confirmed in February 1999. In July 1999, at an early stage of oogenesis, perch from Molnbyggen showed significantly decreased gonadosomatic index (GSI) and aromatase activity. The presence of aromatase inhibiting substances in lake sediments were therefore tested in vitro. The aromatase activity was dose-dependently inhibited by clotrimazole, reaching 50% inhibition at a concentration of 0.9 microM. Aromatase inhibiting substances were found both in Molnbyggen and reference sediment extracts, indicating that they were naturally occurring substances and not of anthrophogenic origin. The similar decrease in levels of circulating steroids (P, 17alpha-OHP, T, and E2), aromatase, and GSI therefore suggest that the low aromatase activity is due to down-regulation rather than inhibition. To further investigate the steroidogenesis prior to T, P, and 17alpha-OHP were analysed in perch caught in 1997 and 1998 in Lakes Molnbyggen, Kvarntjärn (downstream), Yxen (upstream), and Djursjön, in female roach caught in Molnbyggen and Djursjön in 1997, and in brook trout caught in Vadbäcken and the reference stream Björntjärnsbäcken in 1998. The absence of differences in P and 17alpha-OHP levels, combined with a significantly lower T level in female perch and roach from Molnbyggen in 1997, could be the result of either increased metabolism and excretion of T, or a disruption downstream of 17alpha-OHP formation. The unaffected P levels and significantly lower 17alpha-OHP levels, together with significantly decreased T and E2 levels, found in adult (>45g) female brook trout from Vadbäcken, further indicated that an altered steroidogenesis downstream of P is one possible mechanism underlying the low T levels and thus the high number of SIM female fish, since too low T levels might be insufficient to activate the brain-pituitary-gonadal axis

Evidence for endocrine disruption in perch (Perca fluviatilis) and roach (Rutilus rutilus) in a remote Swedish lake in the vicinity of a public refuse dump

A two-year study on perch (Perca fluviatilis) in Lake Molnbyggen, Sweden, located in a pristine area but with a public refuse dump in the vicinity, has been conducted. The mechanistic approach through a set of biomarkers during the first year included age, condition, somatic growth, liver, gonad, and spleen weights, and a number of other physiological variables, in addition to ethoxyresorufin O-deethylase, glutathione-S-transferase, glutathione reductase, catalase, and the formation of DNA adducts in the liver. Perch from the uncontaminated Lake Djursjön, located in a neighboring drainage area, were used as reference fish. The most pronounced effect was a 80␛eduction in the gonadosomatic index (GSI) for females and a corresponding 36␛eduction in males. Fin erosion and shallow open sores were also frequently observed. Biomarkers and later chemical analysis employed indicated that exposure to well-known environmental pollutants was low, suggesting that less well-known antrophogenic substances are responsible for the effects observed in perch from Lake Molnbyggen. During the second year, roach (Rutilus rutilus) of both sexes were also included in this study. In addition, aromatase (P450arom) activity in the brain and testosterone and 17β-estradiol levels in blood plasma were analyzed. Only one-fourth of the female perch were found to be sexually mature, which was associated with decreased GSI, lower P450arom activity, and reduced circulating levels of steroids. The reproductive disorders observed indicates disturbed endocrine function(s), arresting the majority of the female perch in a sexually nonreproducible immature stage. This novel study is the first to report evidence for endocrine disruption in wild populations of fish living in a lake exposed to leakage water from a public refuse dum

Endocrine disruption in brook trout (Salvelinus fontinalis) exposed to leachate from a public refuse dump

Lake Molnbyggen was previously found to harbour a large number of sexually immature female perch (Perca fluviatilis) suffering from endocrine disruption. In an attempt to pin-point the source of the endocrine-disrupting substance(s) (EDSs), brook trout (Salvelinus fontinalis) from Vadbacken, a stream contaminated by leachate from a public refuse dump and which empties into Lake Molnbyggen, were investigated. In addition, female perch from Lakes Yxen and Kvarntjarn, located up-stream and down-stream of Lake Molnbyggen, were investigated. Only 16.7% of the adult female brook trout in Vadbacken were sexually mature, associated with decreased gonadosomatic index, lower brain aromatase activity, and lower circulating levels of testosterone and 17beta-oestradiol, in comparison to female brook trout from the reference stream Bjorntjarnsbacken. Male brook trout showed decreased gonadosomatic index, in addition to bile duct hyperplasia in the liver, which was also found in female brook trout livers from Vadbacken. In Lake Molnbyggen, 57.6% of the female perch were found to be sexually immature with high frequencies of skin lesions, such as sores and fin erosion, significantly decreased gonadosomatic index, lower aromatase activity, and lower levels of testosterone and 17beta-oestradiol. No signs of reproductive disorders or endocrine disruption were seen in female perch from Lakes Yxen and Kvarntjarn compared to female perch from the reference lake, Lake Djursjon. Since brook trout of both sexes from Vadbacken displayed the same kind of serious adverse impairment of gonad development and endocrine disruption as perch from Lake Molnbyggen, very strong evidence are provided that the refuse dump is the source for the responsible EDS(s), since both Vadbacken and Lake Molnbyggen are known to be contaminated by leachate from that dump. The low levels of PAHs and PCBs in the surface sediments of Lake Molnbyggen suggest that these pollutants are not the responsible EDS(s)

The Fabrications and Travels of a Knowledge-Policy Instrument

This article sets forth the main elements of the conceptual framework for the overall approach to the Programme for International Student Assessment (PISA) taken in this special issue. PISA is here examined as a (knowledge for policy) regulatory instrument made by intertwined cognitive and social practices, and involving multidirectional flows of knowledge and policy elements. Additionally – and using materials from a study on the fabrication of PISA – the article gives closer attention to the process of gathering and coordinating the social worlds involved in the making of the instrument, to the plasticity of knowledge for policy and to the fictions – which the instrument carries – regarding education and its governing practices. As a whole, the article relates to the ubiquity of PISA – that is, its conspicuous albeit not similar presence in various geopolitical territories and discursive spaces. Fabricated under the auspices of the Organisation for Economic Cooperation and Development, by bringing together individuals and organisations from various social spaces, its materials and texts generated often reach national and local policy and knowledge contexts, where different social groups have interests in them and are using them differently, though attached to PISA’s dicta on regulatory processes

Aspectos reprodutivos e perfil hormonal dos esteróides sexuais do pirarucu, Arapaima gigas (SCHINZ,1822), em condições de cativeiro Reproductive aspects and sexual steroids hormonal profiles of pirarucu, Arapaima gigas (SCHINZ,1822), in captivity conditions

Esta pesquisa teve como objetivo caracterizar a reprodução e o perfil hormonal dos esteróides sexuais do pirarucu, Arapaima gigas, além de validar um aspecto do dimorfismo sexual secundário. O experimento foi realizado na Fazenda Santo Antônio II, em Presidente Figueredo-AM, no período de fevereiro de 2004 a fevereiro de 2005. Foram selecionados 24 exemplares e divididos em três grupos de oito peixes (grupo "A", "B" e "C" com pirarucus de mais de quatro anos de idade, com três anos e dois anos, respectivamente). Os pirarucus foram estocados em três tanques de 400m², um para cada grupo. Aspectos comportamentais, como o interesse por alimento, brigas, formação de casais e presença de ninhos, foram observados ao longo de todo o experimento. Amostras de sangue foram coletadas mensalmente, de todos os peixes, observou-se a presença de uma mancha alaranjada no macho como uma característica sexual secundária. Foram mensurados os níveis de testosterona (T), 17beta-estradiol (E2) e 17alfa-hidroxi-progesterona (17aOHP) através de radioimunoensaio (RIA) de fase sólida. Todos os machos dos grupos "A" e "B" puderam ser identificados pela mancha alaranjada na região inferior da cabeça, corroborada pela concentração de testosterona, comprovando o conhecimento empírico dos ribeirinhos. Os níveis de T e E2 nos peixes do grupo "A" e "B" tiveram maiores picos no início do período de chuva, enquanto que o 17aOHP teve oscilações constantes e pequenos picos no final do período chuvoso, os peixes do grupo "C" acompanharam essa tendência em concentrações menores.<br>The purpose of this study was to characterize the growth, reproduction and hormonal profile of pirarucu, Arapaima gigas, and validate one sexual dimorphism characteristic. The experiment was carried in the fish farm Santo Antonio II, Presidente Figueredo city in the state of Amazonas Brazil, from February 2004 to February 2005. In the experiment, 24 fishes were selected and divided in three groups, with eight fish in each one. The pirarucus from "A" group were older than four years. In "B" group the fishes were three years old and in "C" group these were two years old. The pirarucus were stocked in 400 m² excavated ponds, one pond for each group. Reproductive behavior like feeding interest, fights, pair formation and presence of nest were observed. Blood samples were taken monthly from all fishes during the experiment period, the sexual dimorphism characteristic was observed. Testosterone (T), 17b-estradiol (E2) and 17ahidroxi-progesterona (17aOHP) levels were measured by radioimunoassay (RIA) in solid phase. All males of group "A" and "B" could be identified by an orange mark under the head, and the levels of T validated this data, proving the empirical knowledge of river men. T and E2 levels of group "A" and "B" picked in the beginning of raining period and the 17áOHP levels were higher in the end of raining period. The levels of these hormones in "C" group fishes followed the tendency of "A" and "B" group hormonal levels, but in lower concentration

Roach (Rutilus rutilus) reproductive cycle: a study of biochemical and histological parameters in a low contaminated site

Fish reproduction is subjected to worrying trends in many aquatic environments. In this study, we report the absence of histological and biochemical alterations in fish sampled in a low contaminated site (characterised by the absence of detectable oestrogenic activity and mutagenicity in sediment extracts). A total of 474 roach (Rutilus rutilus) were monthly sampled during 18 months, and no intersex fish were recorded after careful histological examination, thus indicating that the incidence of this phenomenon may be very low under natural conditions. Furthermore, mean male plasma vitellogenin concentration was 24 ng ml(-1) and was only slightly elevated during the spawning period (up to 120 ng ml(-1)) indicating that these low values may be characteristic of a low contaminated site. Of the male roach, 45.3% were sampled, a sex-ratio that did not significantly deviated from the expected 1:1 ratio between male and female. Results also showed that natural conditions can greatly affect the reproductive cycle of roach. Gametogenesis showed a biphasic pattern with first gonad maturation between September and December and a final maturation occurring at the end of winter/early spring. Under decreasing temperatures, particularly below 6A degrees C, gametogenesis was stopped or even regressed with secondary oocytes becoming rare under histological observation. Conversely, elevated temperatures during the winter lead to an earlier gonad maturation