SUMMARY Previous studies indicated that 36Cl-labelled perchlorate is concentrated by rat and rabbit thyroid gland. However, the extent of concentration of radioactive perchlorate in the gland was much less than that of iodide. Since perchlorate itself has a marked effect on anion transport in the thyroid and the specific activity of available [36C]perchlorate is very low, the stable anion as a carrier present in the injected radioactive perchlorate solution may affect the uptake of this radioactive compound by the gland. In this study, radioactive solutions of perchlorate and iodide containing different amounts of stable perchlorate or iodide (dosages ranged from 0·005 to 5 m-equiv./kg. body weight) were injected into groups of rats and guineapigs, and the thyroid: plasma concentration ratios of radioactive perchlorate and iodide were calculated and compared. These experiments were also repeated in animals pretreated with thyroid-stimulating hormone (TSH), after chronic administration of propylthiouracil (PTU), as well as in hypophysectomized animals. At the same dose levels of perchlorate, there was no difference in thyroid: plasma concentration ratios of radioactive perchlorate and iodide in control rats and guinea-pigs or in treated ones.

Reports from this laboratory (1, 2) and others (3)(4)(5)(6)(7) have demonstrated that the mammalian intestine provides a useful experimental model for studies on the transport mechanisms for electrolytes and nonelectrolytes. The animals used in these studies were mainly rats, rabbits, hamsters, and guinea pigs. The use of mouse intestine as a model system for such studies has not been previously explored.It is generally agreed that the measured ion fluxes and short-circuit current across the mammalian intestine vary greatly with the thickness of the intestine, presumably because of the presence of several layers in addition to the mucosal membrane. Therefore, data obtained with stripped intestinal mucosal membrane is preferable to that obtained with an intact intestine (4, 6 , 7). Since mouse intestine is much thinner than that of mammals previously studied, one wonders would the ion fluxes across the thin intact mouse intestine correspond closely to those observed in the stripped mammalian intestinal mucosa. If so, the mouse intestine could provide a useful and simple tool in future studies on drug effects on intestinal transport systems.Methods. Albino S wiss-Webster mice, weighing an average of 30-40 g were used. They were kept in a constant-temperature room with food and water ad lib. for 7 days or longer after purchase. The mice were killed by decapitation, and the ab-. 3To whom reprint requests should be sent.domen was opened. A section of jejunumileum was removed and opened along the line of mesenteric attachment, rinsed with Ringer solution and mounted in a lucite Ussing chamber having an aperture area of 1.3 cm2. Mammalian Ringer or other isotonic solution was used as bathing fluid. Seven milliliters of bathing solution was pipetted into each of the two chambers separated by the intestinal membrane. The bathing solution was continuously stirred and oxygenated by bubbling with 95% 0,-5% CO, gas. The chamber was kept in a 37°C incubator throughout the experiment. The composition of each bathivg solution is given in Table I. Calomel electrodes were placed close to each side of the membrane for potential difference (PD) measurement. Current was sent through two PbS04 electrodes to zero out the PD and recorded in an Esterline-Angus recorder. The design of the Ussing chamber and the details of the electrical measurements have been described previously (8, 9). Radioactive 22Na and 36Cl were used to measure the sodium and chloride fluxes across the short-circuited intestine. Bathing solutions from both sides were sampled at half-hour intervals and were counted in duplicate in automatic well-scintillation and liquid scintillation counters. Standard 22Na and 36Cl were counted simultaneously with the samples. The ratios of counting of these standard solutions by the two counters were then used to determine the amount of 22Na and 3sCl in the collected samples. Electrolyte fluxes and short-circuit current (Zsc) are expressed in microequivalents (pEq) per square centimeter per hour.Results. Electrical properties of mo...

This study investigated the effects of dietary Ferula supplementation on productive performance, egg quality, follicular development, serum levels of reproductive hormones, and reproductive gene expression in aged laying hens. A total of 300 Dawu pink laying hens (65 weeks old) were assigned to four treatments with six replicates per treatment and 10 hens per replicate. The birds were individually housed in wire cages and fed a corn-soybean meal-based diet with added Ferula at doses of 0, 50, 100, and 200 mg/kg for 12 weeks. The results showed that the laying rate in the 100 mg/kg Ferula-supplemented group was higher than in birds of the control group during weeks 1 to 12 (p<0.05). The average egg weight in the 100 mg/kg Ferula-supplemented group was significantly higher than in the other groups (p<0.01), while the feedto-egg ratio was significantly lower than in other groups (p<0.01). The numbers of small yellow follicle, middle white follicle, and small white follicle were higher in the 100 mg/kg Ferula-supplemented birds than in the other groups (p<0.01). On weeks 69, the serum levels of estradiol, follicle-stimulating hormone, and luteinizing hormone were significantly higher in the 100 mg/kg Ferula-supplemented group than in the other groups (p<0.05). Additionally, expressions of ERα, FSHR, and LHR in the ovarian tissue were up-regulated by Ferula supplementation, especially in the 100 mg/kg group (p<0.01). These results indicate that the Ferula supplementation can significantly improve productive performance, egg quality, reproduction of hormonal profile, and reproductive gene expression of aged laying hens.

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