Heikki Hyvärinen

Contamination of pike and sediment from the Kymijoki River by PCDEs, PCDDs, and PCDFs : contents and patterns compared to pike and sediment from the Bothnian Bay and seals from Lake Saimaa

Sediment and pike from Kymijoki River and Bothnian Bay were analyzed for contents of polychlorinated diphenyl ethers (PCDE), 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF), and non-ortho-substituted polychlorinated biphenyls (coplanar PCBs). Both sites are located in the vicinity of pulp mills. The same compounds were measured in a chlorophenol formulation Ky-5, which used to be used as a wood preservative, and in four ringed seals from Lake Saimaa and in one seal from Lake Baikal. Results of this preliminary study indicated that spills from the manufacture of Ky-5 in the past have contaminated Kymijoki River sediments with PCDEs, PCDDs, and PCDFs. The same PCDE congeners that dominated in these sediments were abundant in Ky-5, pikes from Kymijoki River, and seals from Lake Saimaa. The TEQs of PCDD/PCDFs in the Kymijoki River sediments varied from 0.04 to 59 ng/g dry weight. The contents of PCDE, PCDD, and PCDF compounds were low in sediments and pikes from the Bothnian Bay.

SITE-SPECIFIC FATTY ACID COMPOSITION IN ADIPOSE TISSUES OF SEVERAL NORTHERN AQUATIC AND TERRESTRIAL MAMMALS

Abstract Site-specific differences in fatty acid compositions (by gas-liquid chromatography) were compared in aquatic, semiaquatic and terrestrial mammals: the ringed seals ( Phoca hispida hispida and P. h. botnica ), otter ( Lutra lutra ), raccoon dog ( Nyctereutes procyonoides ), brown bear ( Ursus arctos ) and grey wolf ( Canis lupus ). In addition, we briefly discuss our earlier results for the Canadian beaver ( Castor canadensis ) and muskrat ( Ondatra zibethicus ). In both aquatic and terrestrial species, large amounts of Δ9-monounsaturated fatty acids (MUFAs) and small amounts of saturated fatty acids and exogenous long-chain MUFAs were found in the cold tissues of the extremities. In seals, the poikilothermic outer blubber had these characteristics and differed from the inner blubber. On the other hand, the subcutaneous and inner fat depots of the coated semiaquatic and terrestrial mammals were uniform. In the bare extremities, however, these mammals also had an excess of A9-MUFAs. The degree of Δ9-desaturation in the outer blubber of the seals was significantly correlated with age. The excess of Δ9-MUFAs in the bare extremities of land mammals increased the overall double bond content of these tissues compared with the inner depots. In contrast, due to the large amounts of dietary polyunsaturated fatty acids, this was not found in the aquatic and semiaquatic species. The observed site-specific differences are discussed as possible inherited evolutionary adaptations to low temperature of the tissues.

Seasonal Weight Regulation of the Raccoon Dog (Nyctereutes procyonoides): Interactions between Melatonin, Leptin, Ghrelin, and Growth Hormone

The raccoon dog (Nyctereutes procyonoides, Canidae, Carnivora) is a middle-sized omnivore with excessive autumnal fattening and winter sleep. We studied seasonal weight regulation of the species by following the plasma leptin, ghrelin, and growth hormone (GH) levels of farm-bred raccoon dogs (n = 32) for 6 months. In August, half of the raccoon dogs received continuous-release melatonin implants, and in November, half of the animals of both the sham-operated and melatonin-treated groups were fasted for 2 months. In the autumn, the plasma leptin and GH levels were low, but the ghrelin levels were relatively high and correlated positively with energy intake. This represents the period of energy storage. Leptin and GH levels peaked simultaneously in late October, and melatonin advanced the peaks by 1 week. Thereafter, the levels rapidly declined, representing the transition period from autumnal anabolism to wintertime catabolism. In the winter, the leptin and GH levels rose to high levels, but the ghrelin-leptin ratio was very low. This is the period of winter sleep, with fat accumulated in the autumn as the principal metabolic fuel. In the winter, leptin, ghrelin, and GH may work in synergy to increase lipolysis. GH may also induce winter sleep to the raccoon dog. Fasting had no effect on the hormone levels, unlike in humans and rodents. Instead of the amount of fat in the body, the main regulators of the levels of these hormones in the raccoon dog are presumably seasonal rhythms entrained bymelatonin.

Stratification, Composition, and Function of Marine Mammal Blubber: The Ecology of Fatty Acids in Marine Mammals

This study of vertical fatty acid profiles, based on analysis of 58 fatty acids sampled at 3‐mm intervals throughout the blubber column of a model marine mammal, the ringed seal (Pusa hispida), revealed three chemically distinct layers. The average depths of the outer and inner layers were quite consistent (∼1.5 and ∼1 cm, respectively). Consequently, the middle layer varied greatly in thickness, from being virtually absent in the thinnest animals to 2.5 cm thick in the fattest. The relative consistencies of the thickness and composition of the layers as well as the nature of the fatty acids making up each layer support the generally assumed function of the various layers: (1) the outer layer is primarily structural and thermoregulatory, (2) the inner layer is metabolically active with a fatty acid composition that is strongly affected by recent/ongoing lipid mobilization/deposition, and (3) the middle layer is a storage site that contracts and expands with food availability/consumption. The remarkable dynamics of the middle layer along with the discrete pattern of stratification found in the vertical fatty acid profiles have important implications for methodological sampling design for studies of foraging ecology and toxicology based on analyses of blubber of marine mammals.

Fasting Reduces Plasma Leptin- and Ghrelin-Immunoreactive Peptide Concentrations of the Burbot (Lota lota) at 2°C But Not at 10°C

Abstract The effects of fasting at two water temperatures (2 and 10°C) on plasma leptin- and ghrelinimmunoreactive peptide concentrations and energy metabolism were investigated in the burbot (Lota lota), a freshwater gadoid, which lives in cold waters and tolerates long periods of fasting. Burbot were assigned to fed and fasted groups at 2 and 10°C. Leptin- and ghrelin-immunoreactive peptides were identified in burbot plasma. Fasting at 2°C reduced the plasma leptin- and ghrelin-immunoreactive peptide concentrations and reduced the relative liver weights and the liver and muscle glycogen concentrations. The concentrations of the leptin- and ghrelin-immunoreactivities correlated positively with each other. At 10°C there were decreased plasma thyroxine levels in both sexes, and slightly lower plasma testosterone concentrations in males. The results support previous studies in stating that immunoreactivities resembling mammalian leptin and ghrelin can be detected in burbot plasma and liver, but the specific functions of these peptides will have to be determined in future studies.

Preliminary evidence that pharmacologic melatonin treatment decreases rat ghrelin levels.

Ghrelin is a signal peptide isolated from rat stomach antagonistic to actions of leptin. Ghrelin stimulates the secretion of growth hormone (GH) and increases food intake, body mass, and adiposity in rodents. Photoperiod and melatonin regulate leptin secretion of mammals. The aim of the study was to investigate possible melatonin-ghrelin interactions in weight regulation by studying the effects of continuous pharmacologic melatonin treatment and constant light on plasma ghrelin, leptin, and GH levels in rats. Plasma ghrelin concentrations were significantly reduced by exogenous melatonin. Ghrelin levels correlated negatively with plasma leptin levels in control rats kept in 12 h of light/12 h of dark but not in the melatonin-treated animals. The inverse ghrelin-leptin relationship was also disrupted by constant illumination. The circulating ghrelin and GH levels may not be interrelated in all metabolic situations. The results suggest new interplay between the pineal gland and energy metabolism as well as reenforce the hypothesis that ghrelin is antagonistic to leptin.

Fatty acid composition in liver and blubber of the saimaa ringed seal (Phoca hispida saimensis) compared with that of the ringed seal (Phoca hispida botnica) and grey seal (Halichoerus grypus) from the baltic

1. The main differences in fatty acid composition of blubber between the Saimaa seal (Phoca hispida saimensis) and the Baltic seals (Phoca hispida botnica and Halichoerus grypus) were, that in fresh water the proportions of polyunsaturated C18 acids and arachidonic acid (20:4 omega 6) were high. 2. The trend became more evident when data on ringed seals from northern oceans were compared with the present data. 3. The proportions of exogenous 20:1 and 22:1 were extremely low in ringed seals from Lake Saimaa and in Baltic seals compared with seals living in oceans.

Heavy metals and high pup mortality in the Saimaa ringed seal population in Eastern Finland

Abstract Hair nickel, mercury, cadmium, lead and chromium concentrations were measured from still-born ringed seal pups and from other ringed seal groups from Lake Saimaa in Finland. Nickel concentration was significantly higher in the hair samples of still-born pups as compared to live-born pups and to adult seals. There was assumed to be some connection between the stillbirth of the pups and nickel concentration of the hair. Mercury concentration of the natal hair of pups was significantly higher than the mercury concentration of the first adult hair but no clear connection between stillbirth and mercury pollution was observed. No differences were observed in cadmium, lead and chromium concentrations of the hair of still-born and other ringed seal groups.

Toxic effects of mining effluents on fish gills in a subarctic lake system in NW Russia

The mining company Karelian Pellet in northwestern Russia extracts iron ore and processes it locally into pellets. The production operations affect the environment in the form of air pollution and wastewater emissions to lakes downstream from the factory. The toxic effects of the mining effluents on gills of perch (Perca fluviatilis) and roach (Rutilus rutilus) were studied. In lakes close to the factory, heavy metal concentrations in gills were not high, even though the metal content in sediment was elevated. In fish gills the relative proportion of phosphatidylcholine was elevated and cholesterol reduced, while the histological structure of the gills was changed. The number of mucus cells, as well as the sizes and the lengths of open areas in the chloride cells, had increased in spring and summer. The hypertrophy of chloride cells is possibly caused by the increased ambient concentrations of K+ and Li+. Changes in gill cholesterol and phospholipid proportions increase the fluidity of membranes and possibly strengthen their protective qualities, counterbalancing the adverse changes in chloride cell structure. The bioavailability and toxic effects of metals on fish are reduced by the hardness and high pH of water discharged by the mining plant.

Effects of nickel chloride on reproduction of the rat and possible antagonistic role of selenium

Nickel (10-100 ppm added as NiCl2) was studied to determine its effects on reproduction of Wistar rats. In nine experimental groups, females, males or both were exposed to nickel in drinking water. In one female group and one male group, the drinking water was also supplemented with 0.3 ppm selenium (added as Na2SeO3). Breeding success and the growth and viability of pups were recorded. Nickel, copper and zinc concentrations in kidneys, liver and skin (with fur) of the females, males and pups were determined with an atomic absorption spectrophotometer. In addition, histology of the male testes (from control and nickel-exposed groups) was studied. The female exposures started 14, 28 or 100 days before copulation and continued during pregnancy and lactation. When the males were exposed (for 28 or 42 days before copulation), NiCl2 reduced both the number of pregnancies and the number of pups born. In the testes, NiCl2 induced shrinkage of the seminiferous tubules, which seemed to close some of the tubules. In the tubules, NiCl2 decreased the number of basal spermatogonia. When the females or both parents were exposed to NiCl2, pup mortality during lactation was high. However, when the females were drinking NiCl2 supplemented with selenium, all the pups survived and development of the total mass of the litters was even better than in the control group. In the same way, in males, selenium supplementation of the drinking water protected those pups that were born; but fertility was lower than with the control treatment. In the tissues studied, nickel accumulated most in the kidneys and then in the liver and skin. In each type of organ, there was a clear dose response relationship. In the pups, in particular, selenium (given to the females) increased the amount of nickel in tissues compared with corresponding administration of nickel without selenium. In summary, selenium seemed to counteract the deleterious effects of NiCl2 on the reproduction of rats.