Photoreception and circadian rhythms in the eye, pineal and brain of Japanese quail

s45

Symposium 31: Environmental endocrine disruptors and their impact on growth and development. Chair: G. Van der Kraak (Canada)

s30-5

Lighting

environment

arylalkylamine Mizusawa

regulates

mRNA level of

N-acetyltransferase

s31-1

in trout retina.

K’, Iigo MZ and Aida K’

‘Department

of Aquatic

Bioscience,

Graduate

School of

Agricultural

and Life Sciences, The University

of Tokyo,

Tokyo, Japan 113-8657 ‘Department

of Anatomy,

St. Marianna

of Medicine,

Kawasaki,

Japan 216-8511

Melatonin

production

controlled

by both a circadian

environment

However, darkness

clock and lightning activity

(AANAT)

is absent or very weak in

trout. In this study, effects

on AANAT

of light and

levels in the retina were

mRNA

tested. Under light-dark

of arylalkylamine

in most vertebrates.

the clock regulation

the rainbow

School

in the pineal organ and retina is

via the oscillating

N-acetyltransferase

University

cycles,

AANAT

mRNA

levels

were higher during the dark phase than during the light phase. Under constant did not exhibit low levels,

darkness

significant

respectively.

or light, AANAT

tluctuations

Thus, transcription

of the AANAT

gene in the trout retina lacks the regulation clock but is regulated

by lightning

mRNA

and kept high and by a circadian

environment.

Effects of xenobiotics on adrenal steroidogenesls and growth in fish. Hontela' A., Leblond’V., S herwood*G and Rasmussen*JB 1-Dept. Sci. Biologiques, Univ. du Qu6bec g Montreal; 2Dept. of Biology, McGill University, MontrBal, Canada H3C 3P8 Metals activate the hypothalamo-pituitary-interrenal axis and elevate plasma cortisol in teleost fish. We have demonstrated, using a bioassay for adrenal steroidogenesis, that acute in vitro exposures to metals such as Cd, disrupt the capacity to respond to ACTH or dbcAMP at doses of metals that do not induce cell mortality. We have also used functional tests in viva and in vitro, to show that the capacity to generate the cortisol stress response, an adaptive homeostatic res ponse, is normal in fish exposed for 30 days to Cd in viva in the laboratory, However, the capacity to respond to ACTH is disrupted in fish chronically exposed to metals in the field. Cortisol secretion in response to ACTH and dbcAMP of the interrenals from fish sampled in conta minated lakes is lower than in fish from a reference lake. Growth efficiency (conversion of ration to body mass) of contaminated fish is also lower, blood glucose levels in response to acute confinement stress are lower and liver glycogen reserves are higher, compared to reference fish. Our data suggest that adrenal steroidogenesis is impaired when specific tissue burdens of metals are reached and that this endocrine disruption has adverse effects on the metabolic status and growth of fish.

S30-6 Photoreception

and

circadian

pineal and brain of Japanese

Oishi,

rhythms

in

the

eye,

The effects of endocrine disrupters on sea water adaptability, growth and survival of salmon smolts.

quail.

Yamao M., Moriyasu N., Kondo C., Haida Y. and

Tamotsu S Department of Biological Sciences, University, Nara, Nary, Japan 630-8506

Nara

Women’s

Photoreceptors and circadian oscillators are closely related in their location and function.

In birds, the eye, pineal

and deep brain have been known to have fimction circadian

oscillators

as well as photoreceptors.

as

Firstly,

we studied the role of the eye, pineal and deep brain in the multi-oscillator for circadian behavioral (locomotor activity and feeding/drinking) rhythms. Secondly, a developmental study was performed on the appearance of visual pigments and melatonin rhythms in the eye and pineal of quail embryos. Thirdly, we investigated circadian

retinal melatonin

rhythms and cornea1 mitotic

rhythms and found that there are independent for each of the retinal and cornea1 rhythms. investigated distribution and morphology of immunoreactive neurons in the paraventricular relation to VIP-immunoreactive

neurons.

S31-2

oscillators Lastly, we serotoninnucleus in

Brown SB’ Fairchild WL2 Haya K3 Burridge LE3 Swansburg E02 Arsenault JT2 Sherry J’ Bennie D’ and Eales JG4 ‘Environment Canada, National Water Research Institute, Burlington, Ontario, Canada, 2Fisheries & Oceans Canada, Gulf Fisheries Centre, Moncton, New Brunswick, Canada; 3Fisheries & Oceans Canada, St. Andrew’s Biological Station, St. Andrew’s, New Brunswick, Canada; 4Department of Zoology, University of Manitoba, Winnipeg, Manitoba, Canada We investigated the hypothesis that environmental estrogens, like p-nonylphenol(4-NP) and 17D-estradiol (E2), may disrupt Parr-smolt transformation in Atlantic salmon (Sulmo sah). Atlantic salmon smolts were exposed to environmentally relevant, pulse doses of water-borne 4-NP (20 &L) and more sustained doses of E2 (100 rig/L))during the latter stages of smoltification. The capability of smolts to withstand sea water and their subsequent growth were evaluated.. There were no treatment related increases in mortality during a sea water challenge immediately after exposure. However, subsequent growth and survival in sea water was impaired in up to 30% of fish from the various treatment groups. These findings suggest that estrogenic activity stemming from current effluent sources (e.g., domestic sewage, agricultural wastes or phytoestrogens from pulp mills) may influence the long-term sea water adaptability and survival of salmon smolts.