Theodore H. Kerstetter

Changes in the fatty acid composition of steelhead trout, Salmo gairdnerii Richardson, associated with parr-smolt transformation.

Fatty acids from the several lipid classes of selected steelhead trout (Salmo gairdnerii) parr and smolt tissues, previously separated by thin-layer chromatography, were analyzed by gas-liquid chromatography. The fatty acid composition of the parr was markedly different from that of the smolt; the former being characterized by relatively low amounts of polyunsaturated fatty acids and relatively high amounts of linoleic acid, much like the typical freshwater lipid pattern. The fatty acid composition of the smolt was characterized by large proportions of long-chain polyunsaturated fatty acids. Generally, the fatty acid composition of the smolt resembled the typical seawater lipid pattern. The change in fatty acid composition of the smolt is anticipatory to seawater entry and is independent of diet and water temperature. These alterations suggest that the assumption of a polyunsaturated lipid pattern during parr-smolt transformation (smoltification) is preadaptive to seawater entry.

HCO3−-Dependent ATPase activity in the gills of rainbow trout Salmo gairdneri

Abstract 1. 1. A HCO3− activated ATPase is present in both fresh water and sea water adapted rainbow trout gills. The apparent Km for HCO3− is 0·016 M. 2. 2. Both the ATPase and active Cl− uptake by intact gills are inhibited by SCN−, but by apparently independent mechanisms. 3. 3.Cl− is not required for activation of the ATPase; at [Cl−] greater than 0·010 M, enzyme activity is inhibited 4. 4. The intracellular location of the HCO3− ATPase is unclear, but preliminary evidence suggests it is both mitochondrial and microsomal.

Changes in intestinal water absorption in coho salmon during short-term seawater adaptation: a developmental study

Abstract Intestinal water absorption of juvenile coho salmon smolts, pre-smolts, and post-smolts as a function of seawater adaptation was investigated. Net water absorption (Jv) of mid and posterior gut sections in vitro did not change markedly from the freshwater state through 7 days of salt water exposure, although long-term seawater residents had a higher Jv in posterior gut segments, and post-smolts had lower Jvs in both segments than smolts. Rectal fluid [Na+] and pH, and liver [K+], changed in distinctive ways during the first 7 days in seawater, and the changes are compared between developmental stages. Ion analysis of intestinal fluid from different segments of the gastrointestinal tract of seawater-and freshwater-adapted coho indicates that ingested seawater is slightly diluted in the stomach, that 95% or more of the water absorption in seawater-adapted fish occurs in the anterior intestine and pyloric caecae, and that the mid and posterior intestine may be important in water absorption only in the initial stages of seawater adaptation.

Intracellular electrolyte regulation in freshwater- and seawater-adapted coho salmon

Abstract Concentrations of sodium and potassium were analyzed in liver tissue taken from freshwater- and seawater-adapted coho salmon smolts, and from seawater stunts. Total potassium, related to dry weight, was significantly higher in the stunts than in either the freshwater or seawater smolts. Tissue slices incubated in Ringer solution under 100% oxygen showed a similar trend, although statistical significance was only marginal. Tissue sodium was not significantly different among the three groups of fish.

Changes in plasma somatostatin associated with seawater adaptation and stunting of coho salmon, Oncorhynchus kisutch

Abstract Somatostatins (SSs) are a family of peptide hormones made up of different molecular forms that have been found to modulate various aspects of growth, development, and metabolism of vertebrates. In this study, coho salmon ( Oncorhynchus kisutch ) were used to evaluate the role of SSs in seawater (SW) adaptation. In experiment 1, pre-smolt and smolt coho salmon (age=1–1.5 years) were transferred to SW and sampled at zero, one, two, and seven days later. For both pre-smolts and smolts, plasma SS-25 concentrations rose following SW exposure and reached peak levels two days after transfer; thereafter, levels gradually declined. Interestingly, SS-25 levels were higher in pre-smolts than those in smolts, a difference that was similar to that noted for rectal [Na + ] and indicating a greater state of SW readiness for the smolt group. In experiment 2, pre-smolt coho salmon were transferred to SW and sampled eight weeks later. Pre-smolt SW exposure resulted in significant growth retardation (stunting). Plasma levels of both SS-25 and SS-14 were significantly higher in stunts than those in their normal (SW smolt) counterparts. These results indicate that changes in SSs accompany SW adaptation and that SSs may be involved with stunting associated with premature SW transfer.

Increase in Ocean Survival of Freely Migrating Steelheads Vaccinated Against Vibrio anguillarum

Abstract Steelheads (Salmo gairdneri) were vaccinated as juveniles against two serotypes of Vibrio anguillarum, marked, and allowed to migrate freely to the sea. A statistically significant (P ⩽ 0.01) 19.3% increase in return rate of adults to the hatchery occurred among the vaccinated group compared to the nonvaccinated control group. No difference between groups was found in the size or sex ratio of returning fish.

Reduced prolactin response to exercise in amenorrheic athletes

Abstract Plasma prolactin (PRL), 17‐s estradiol (E2) and progesterone of eight college‐age amenorrheic (AM) and 21 endurance athletes with regular menses were determined by radioimmunoassay from blood samples taken just before and immediately following a 45 min training run. Baseline PRL was 14.4 ± 1.4 (s.E.M.)ng ml‐1 for the AM group and 16.4 ± 2.1 ng ml‐1 for the controls. Post‐exercise PRL was 17.3 ± 1.8 ng ml‐1 for the AM athletes and 46.8 ± 7.3 ng ml‐1 for controls, a difference which was statistically significant (P <0.05). Mean levels of E2 of AM subjects increased from 40 ± 13 to 60 ± 18 pg ml‐1 following exercise, and from 118 ± 23 to 182 ± 35 pg ml‐1 in controls. Pre‐exercise and post‐exercise E2 differences between AM and control athletes were statistically significant (P <0.05), as were the exercise‐associated increases (P < 0.05 for AM and P < 0.005 for controls). Plasma progesterone was unaffected by exercise. The AM athletes weighed less and ran more miles weekly but were similar to the con...