Paul M. Mehrle

The effect of early and midday prolactin injection on the lipid content of fundulus kansae held on a constant photoperiod

Abstract 1. 1. Ovine prolactin caused different effects upon the lipid content of the euryhaline teleost, Fundulus kansae, depending upon the time of injection. 2. 2. Prolactin administered in the early hours of a 16-hr photoperiod caused a 19 per cent decrease in total body lipid, when administered during the middle of the photoperiod, total body lipid increased 22 per cent. 3. 3. The affected lipids were primarily even-numbered, long-chain fatty acids in the C-14 to C-24 range. 4. 4. Results with hypophysectomized animals were similar, with a 13 per cent decrease in lipid noted after prolactin injections given early in the photoperiod, and a 13 per cent increase in lipid after midday injections.

Ammonia detoxifying mechanisms of rainbow trout altered by dietary dieldrin.

Abstract Dietary dieldrin dosages of 14, 43, 143 and 430 μg/kg body weight per day for 240 days altered ammonia detoxifying mechanisms and brain amino acid metabolism of rainbow trout. These dosages corresponded to 0.36, 1.08, 3.6, and 10.8 μg dieldrin/g food, respectively. Whole-body dieldrin residues in fish from the lowest 3 dosage groups were comparable to those found in fish from the aquatic environment. The brain concentrations of amino acids associated with ammonia detoxifying mechanisms, aspartate, glutamate and alanine, were significantly altered, as were the enzymes related to their metabolism. Brain glutamate dehydrogenase (GDH) activity was decreased by all doses of dieldrin, whereas liver GDH and brain glutamine synthetase activities were stimulated by all treatment doses. Brain ammonia concentrations increased in the groups given the 2 highest dosages. Mitochondrial morphology in liver cells was significantly altered by dieldrin treatment as determined by electron microscopy. Since GDH is an intramitochondrial enzyme, examination by electron microscopy gave further evidence that dieldrin significantly altered mitochondrial metabolism. A possible mode of action of dieldrin was proposed which suggests that dieldrin inhibits or decreases brain GDH activity followed by ammonia intoxication after liver GDH and brain glutamine synthetase activities are exceeded. The ammonia detoxifying mechanisms of fish seemed to be very sensitive to dieldrin; the “no-effect” dosage was below 14 μg/kg body weight per day (0.36 μg/g food).

Serum characteristics of spawning (Polyodon spathula)

Abstract 1. 1. Parallel estimates of thirteen serum parameters were made in four female and eight male paddlefish taken at spawning. 2. 2. Sexual “dimorphism” was found in serum non-protein nitrogen, cholestrol, and cortisol. 3. 3. Although paddlefish appeared to regulate the major electrolyte, Na, K and Cl, similar to other freshwater teleost, both sexes had lower serum Ca, NPN, protein and glucose concetrations. 4. 4. Low serum Ca levels in paddlefish suggest physiological hypocalcemia and, in this respect, paddlefish show phylogeneitc affinity to the other chondrostei, the sturgeons.

Serum amino acids in rainbow trout (Salmo gairdneri) as affected by DDT and dieldrin

Abstract 1. 1. Serum amino acid concentrations of rainbow trout ( Salmo gairdneri ) were determined by gas-liquid chromatography. 2. 2. Total serum amino acid concentrations were significantly increased by chronic exposures of DDT and dieldrin administered in the diet for 140 days. 3. 3. DDT altered the concentrations of 9 amino acids, and dieldrin altered the concentrations of 11. 4. 4. In untreated fish subjected to forced swimming for 6 hr and 24 hr, concentrations of all amino acids decreased except for arginine and alanine 5. 5. There was a significant interaction between pesticide treatment and forced swimming in regard to total serum amino acid concentration, and the concentrations of 11 amino acids.

Phenylalanine determination in fish serum: Adaptation of a mammalian method to fish

Biochemical methods originally designed for mammalian tissues are not, in all instances, directly adaptable to tissues from other species, such as fish. Consideration must be given to the biochemical profile of the research animal to which an analytical method is to be applied. In particular, when adapting a method for an amino acid such as phenylalanine from mammalian serum to fish serum, one must be aware of the relative concentration of the amino acid and also the total amino acid concentration in each species. Chance (1) reported that the total amino acid concentration of salmon plasma was two to three greater than that of swine. The level of each essential amino acid was three to six times higher in salmon than in pigs. We herein report a fluorimetric assay adapted from a mammalian method for the quantitat,ive determination of phcnylalaninc in fish serum. The fluorimetric method is based on the interaction of phcnylalanine with ninhydrin and the peptide leucyl-alanine. The greater concentration of amino acids in fish serum necessitates adding more of the ninhydrin-peptide reagent to the reaction to obtain quantitative results. McCaman and Robins (2) reported a quantitative fluorimetric method for phenylalanine in mammalian serum. The reproducibility [(SF/X) X 1001 was one to t.hree percent, and the accuracy (recovery from spiked sample) was 97%. This fluorimetric assay was based on the observation of Lowe et al. (3) that the fluorescence resulting from the reaction of phcnylalanine and ninhydrin was increased by the addit’ion of the peptide glycyl-m-phenylalanine. However, this fluorrsccnt reaction was not specific for phenylalanine, whereas McCaman and Robins found that using the peptide L-leucyl-L-alanine gave a specific, sensitive reaction for phenplalanine. This procedure involved adding 0.3 M succinate buffer (pH 5.8)) 30 nlM ninhydrin, and 5 mM L-leucyl-L-alanine in a volume ratio of 10:4:2, respectively, to deproteinized serum filtrate. After incubation of this mixture for 2 hr at, 6O”C, a copper solution was added and the resulting fluorescence measured at 392 nm excitation and 492 nm fluorescence. A modification of this method was outlined in Sigma Tentative Technical Bulletin No. 60-F1 (4) in which 0.6 M succinate buffer (pH