Spontaneous and induced metamorphosis in the American brook lamprey, Lampetra appendix

Abstract

Abstract:We described the seven stages of spontaneous metamorphosis in the American brook lamprey (Lampetra appendix) and assessed the importance of size as a determinant of spontaneous and induced metamorphosis. Serum concentrations of the thyroid hormones (TH) thyroxine (T 4 ) and triiodothyronine (T 3 ) were measured in metamorphosing and nonmetamorphosing L. appendix. The sequence of stages in metamorphosis and changes in the relative lengths of most body regions were consistent with data reported for other lamprey species. However, premetamorphic and metamorphosing L. appendix in the early stages of metamorphosis (1-3) were much larger in size (at least 155 mm and 5.40 g) than has been observed for other lamprey species. Serum concentrations of T 4 and T 3 were high by the end of the larval period and declined significantly by stage 2 of metamorphosis. Larvae ≥130 mm in length were treated with either potassium perchlorate (KClO 4 ; 0.01 and 0.05%) or 10 mg/L propylthiouracil (PTU; 0.0001%) for 117 days from September to January to determine if metamorphosis could be induced by these goitrogens. Both concentrations of KClO 4 successfully induced metamorphosis in L. appendix, but the incidence of metamorphosis (62%) was much lower than reported in sea lampreys (98%) of comparable size. Serum concentrations of T 4 and T 3 declined by 64-76 and 93-96% relative to control values, respectively, in metamorphosing and nonmetamorphosing L. appendix treated with KClO 4 . PTU elicited declines of 55% for T 4 and 80% for T 3 , but only one animal metamorphosed. Based on these data, we conclude that a decline in serum TH levels is necessary for metamorphosis in L. appendix, but not sufficient by itself to trigger the process.Résumé : On trouvera ici la description des sept stades de métamorphose spontanée chez la lamproie (Lampetra appendix); nous avons évalué l'importance de la taille comme facteur déterminant de la métamorphose spontanée et de la métamorphose provoquée. Les concentrations sériques des hormones thyroïdiennes (TH) thyroxine (T 4 ) et triiodothyronine (T 3 ) ont été mesurées chez des lamproies en métamorphose et chez d'autres lamproies non en métamorphose. La séquence des stades de métamorphose et les modifications de la longueur relative de la plupart des zones du corps correspondent aux données signalées pour d'autres espèces. Cependant, chez cette espèce, les lamproies prémétamorphiques et les lamproies en métamorphose au cours des premiers stades (1-3) sont de taille bien supérieure (au moins 155 mm et 5,40 g) à celle mesurée chez d'autres espèces. Les concentrations sériques de T 4 et de T 3 sont élevées à la fin de la période larvaire et diminuent considérablement jusqu'au stade 2 de la métamorphose. Nous avons administré du perchlorate de potassium (KClO 4 ; 0,01 et 0,05%) ou 10 mg/L de propylthiouracil (PTU; 0,0001%) à des larves de longueur ≥130 mm durant 117 jours, de septembre à janvier, afin de vérifier si ces goitrogènes peuvent provoquer la métamorphose chez les poissons. Les deux concentr...

KClO4 inhibits thyroidal activity in the larval lamprey endostyle in vitro

“…More recent studies have focused on the ability of goitrogens to lower serum TH concentrations and induce precocious metamorphosis in lampreys (Hoheisel and Sterba, 1963;Holmes and Youson, 1993;Holmes et al, 1999;Leatherland et al, 1990;Manzon et al, 2001;Suzuki, 1986Suzuki, , 1987Youson et al, 1995). These studies support the view that spontaneous metamorphosis is linked to a decline in serum TH concentrations (Lintlop and Youson, 1983;Wright and Youson, 1977).…”

“…American brook lampreys greater than 130 mm in length were collected in the fall from Duffins Creek in Ajax, Ontario, and housed as described above. It has been shown that KClO, also depresses serum TH concentrations and induces metamorphosis in L. appendix (Holmes et al, 1999).…”

Development of freshwater water-quality criteria for perchlorate

“…A number of studies containing acute and chronic toxicity data for the species Daphnia magna [28], P. promelas [24–26], the coelenterate Hydra attenuata [29], the Argentine toad B. arenarum [17], the African clawed frog X. laevis [18,30], the lampreys L. appendix [16], and Petromyzon marinus [15] did not meet the U.S. EPA's minimum requirements for use in developing water‐quality criteria because of the use of non‐native species, unacceptable dilution waters, differences in the length of exposure, excessive mortality among the control population, and probable toxicity from the ammonium, sodium, or potassium perchlorate counterion. Also, plant tests with the algae Chlorococcales [31], Scenedesmus quadricauda [32], and Microcystis aeruginosa [32] did not meet requirements for use in criteria development, because the tests did not include a control, exposures were not of sufficient duration, and supporting information was not available.…”

“…The chronic value is the geometric mean of the lowest-observable-effect concentration (LOEC) and the no-observable-effect concentration (NOEC). EA also measured an acute perchlorate LC50 of 490 mg/L for the cladoceran crustacean Daphnia magna [24], an acute LC50 exceeding 1,000 mg/L (the highest tested concentration) for the amphipod Hyalella azteca [25], and an acute LC50 of 1,655 mg/L [24] and chronic value exceeding 490 mg/L [25] with the fathead minnow (Pimephales promelas) ( A number of studies containing acute and chronic toxicity data for the species Daphnia magna [28], P. promelas [24][25][26], the coelenterate Hydra attenuata [29], the Argentine toad B. arenarum [17], the African clawed frog X. laevis [18,30], the lampreys L. appendix [16], and Petromyzon marinus [15] did not meet the U.S. EPA's minimum requirements for use in developing water-quality criteria because of the use of non-1444 Environ. Toxicol.…”

Effect of Somatostatins and Insulin on Blood Glucose Levels of Larvae and Metamorphosing Landlocked Sea Lamprey, Petromyzon marinus

“…It has been suggested that thyroid hormones (TH; thyroxine, T 4 , and triiodothyronine, T 3 ) are important factors in the metamorphic development of lampreys (Youson, 1997). This notion is supported by the observation that TH deficiency, caused by treatment with goitrogens, induces precocious metamorphosis of four Northern Hemisphere lamprey species, Lampetra planeri (Hoheisel and Sterba, 1963), L. reissneri (Suzuki, 1986), P. marinus (Youson et al ., 1995), and L. appendix (Holmes et al ., 1999). In addition, TH treatment completely blocked KClO 4 -induced metamorphosis (Manzon et al ., 1998) and inhibited KClO 4 -induced changes in lipid metabolism that are similar to those observed during spontaneous metamorphosis (Kao et al ., 1999a).…”