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The effects of steroids (17 alpha-methyltestosterone (MT), 17 beta-oestradiol (E2)), and of sex reversal (XX male) on intestinal absorption and accumulation of L-[14C]leucine (5 mM), were investigated in unanaesthetized rainbow trout (Salmo gairdneri), using an in vivo gut perfusion technique. Each steroid was luminally perfused through the gut at a concentration of 50 micrograms/ml perfusate, during five separate perfusions carried out on the same fish at 30-min intervals (perfusion periods 1 to 5), for a total of 120 min at 14 degrees. Experiments were also conducted on masculinized, genetically female trout (XX male) with steroid-free perfusate. MT treatment significantly increased the intestinal absorption of radioleucine during periods 1 and 2, whilst E2 was without effect. Neither MT nor E2 influenced intestinal accumulation (mid- and hindgut) of radioleucine, and accumulation of 14C-solutes in skeletal muscle. Sex reversal, however, whilst having no effect on leucine absorption, nevertheless significantly increased intestinal accumulation of radioleucine, and accumulation of 14C-solutes in skeletal muscle. The effects observed in the present study are in agreement with previous work in trout using everted gut sac preparations. It is suggested that the growth-promoting effects of anabolic-androgenic steroids in fish may be partly explained by their action on gastrointestinal function.

The in vivo dynamics of bolus-injected, unlabelled bovine insulin in eels (Anguilla anguilla L.), analysed by compartmental and noncompartmental methods, were found to be significantly influenced by acclimation temperature and insulin dose level. At 12 degrees, plasma clearance of insulin was essentially monoexponential, whereas at 22 degrees, the disappearance curves could be resolved into two exponential components. Metabolic clearance rate (MCR) and apparent distribution volume (Vdist) of insulin were significantly higher at 22 degrees than 12 degrees, and irrespective of temperature, MCR was more rapid at a lower (130 mU/kg) than a higher (260 mU/kg) dose, while Vdist was more variable in this respect. These results indicate that the dynamics of insulin in eels are temperature-sensitive, and that over the dose range employed, routes of insulin elimination are saturable. Of particular significance were the inordinately high values for derived Vdist indicating that following bolus injection, substantial loss of the hormone occurred.

The effects of D-glucose on the differential secretion of glucagon-like (GLI) and somatostatin-like (SLI) immunoreactivity have been studied using the perfused eel pancreas. During control perfusions with 2.7 mM glucose, basal secretion of GLI and SLI remained essentially stable for a period of 46 min, with an overall mean rate of 381 +/- 20 and 268 +/- 23 pg/min/100 mg dry wt of pancrease, respectively. An acute increase in perfusate glucose to 8.3, 16.7, and 33.3 mM resulted in a monophasic, dose-dependent decline in GLI secretion over 30 min. However, acute return of control glucose concentrations (2.7 mM) from 16.7 or 33.3 mM did not result in return of GLI to control levels, whereas from 8.3 mM glucose this was achieved slowly. By contrast, 8.3 mM glucose was without effect on SLI secretion, but at 16.7 and 33.3 mM a dose-dependent, biphasic pattern of release was evident, with a rapid return to control SLI levels during the terminal perfusion period with 2.7 mM glucose. The results suggest that the A and D cells of teleosts are sensitive to changes in glucose concentration, and, in terms of secretory profiles, release of GLI, and SLI, are qualitatively similar to those of mammals.

The Rotalex test, a commercial latex agglutination test for rotavirus, was compared with direct electron microscopy (EM) and the Rotazyme test I, a commercial enzyme immunoassay, for detection of rotavirus in stools of children and neonates. For initial stool specimens from 265 children (less than 3 years old) with diarrhea, the Rotalex test had a sensitivity of 81.7% and specificity of 99.5% compared with EM results. Positive and negative predictive values were 98 and 94.9%, respectively. The Rotalex test was slightly more sensitive and specific than the Rotazyme test. When daily stool specimens from patients with rotavirus gastroenteritis were examined, the sensitivity of the Rotalex test varied depending on the time of stool collection relative to the onset of symptoms. Sensitivity was 100 (20/20), 96 (23/24), and 54% (7/13) during 1 to 4, 5 to 7, and 8 to 18 days, respectively, after the onset of symptoms. The sensitivity of the Rotazyme test varied similarly with days from onset. We also examined 214 EM-negative stool specimens from asymptomatic newborns. False positivity by the Rotalex test was only 3.3% (7/214) compared with 4.2% (9/215) for the Rotazyme test. The Rotalex test was as sensitive and specific as EM for detection of rotavirus during the acute stage of illness and much faster and cheaper than EM or the Rotazyme test. The test appears to be suitable for routine use in small hospitals, emergency wards, or even the physician's office for rapid diagnosis of rotavirus gastroenteritis.