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The appropriate period of antithyroid drug (ATD) discontinuation before radioiodine therapy is the most critical problem in Graves' disease patients under going treatment with ATD. To determine the optimal period that does not alter the outcome of radioiodine therapy or exacerbate hyperthyroidism, we compared serum FT4 levels at radioiodine uptake (RAIU) and therapy outcomes between a 2-day withdrawal group and 7-day withdrawal group. We prospectively recruited 43 patients for the 2-day withdrawal protocol and retrospectively reviewed 49 patients treated with radioiodine following the protocol of 7-day withdrawal. There was no significant difference in RAIU between the 2 groups. The mean serum FT4 level measured on the first day of 24-h RAIU of the 7-day group was significantly higher than that in the 2-day group. There were no significant differences in the outcomes at each point (6 months, 1 year, and 2 years after therapy) between the 2 groups. Our results indicated that withdrawal of ATD for 2 days is superior to 7 days in that 2 days discontinuation did not exacerbate hyperthyroidism. In order to prevent serum thyroid hormone increase after ATD withdrawal and radioiodine therapy, a 2-day ATD withdrawal period before radioiodine therapy may be useful for high-risk patients such as the elderly and patients with cardiac complications. We believe that the 2-day ATD withdrawal method may be useful for patients undergoing treatment with ATD who are to undergo radioiodine therapy.

After intracerebroventricular administration, both interleukin-1 alpha and corticotropin-releasing hormone increase nociceptive thresholds evaluated by the hot-plate test in the rat. Pretreatment with 6-hydroxydopamine or prazosin fully prevents the action of both substances. Moreover, the effect of interleukin-1 alpha is completely blocked by the intracerebroventricular administration of the corticotropin-releasing hormone antagonist alpha-helical CRH 9-41. Our results suggest an involvement of CRH and the noradrenergic system in the antinociceptive effect of central interleukin-1 alpha.

In order to evaluate the effects in adults of different doses of ACTH 1-17 on the cortisol and aldosterone secretion, 200 micrograms of ACTH 1-17 were injected i.m. at 07(00) in two groups of 6 patients each of both sexes. Sampling was done before and after ACTH 1-17 administration at 4-h intervals from 08(00) to 04(00) in order to define the circadian profiles of both cortisol and aldosterone. At the time of study all subjects were kept under the same routine conditions. The i.m. injection of 100 micrograms of ACTH 1-17 was followed by a maximum response of cortisol which coincided with the physiological circadian peak of the hormone (511.7 +/- 122.7 vs 195.5 +/- 92.9 ng/ml; mean +/- 1 SD; p less than 0.001). With this treatment no variations in the normal circadian rhythm were observed. After the injection of 200 micrograms ACTH 1-17, a marked variation in the circadian rhythm of cortisol (peak at 16(00): 390.0 +/- 49.8 ng/ml; mean +/- 1 SD) was observed. Significant variations in the circadian rhythm of aldosterone with respect to the normal profile were observed only after the injection of 200 micrograms ACTH 1-17 (peak at 16(00): 137.5 +/- 50.5 vs 50.8 +/- 36.1 ng/ml; mean +/- 1 SD; p less than 0.01). The hormone increase observed after the injection of 100 micrograms (peak at 08(00): 111.7 +/- 87.5 vs 61.3 +/- 16.5 ng/ml; mean +/- 1 SD) was not statistically significant. Our results indicate that the clinical use of ACTH 1-17 i.m. is not recommended at doses greater than 100 micrograms.(ABSTRACT TRUNCATED AT 250 WORDS)

THE plant hormone abscisic acid (ABA) is thought to be involved in the regulation of transpiration through its effects on stomatal aperture1. Application of synthetic ABA causes stomatal closure in whole plants2, shoots3 and leaf epidermal strips4. During water stress, levels of the hormone increase in plant tissues5, including the leaf epidermis6, and this is usually associated with stomatal closure7. There is evidence that ABA affects the ionic8,9 and metabolic9 status of the stomatal complex and it has been concluded that ABA acts directly on guard cells in effecting stomatal closure8,10,11. There is, however, little information about the distribution of ABA in specific cells of the epidermis or about the sensitivity of the stomatal complex to ABA. We present here evidence that ABA can accumulate in the stomatal complex of Commelina communis L., a species used extensively in studies of stomatal physiology12. The leaves of this plant yield relatively uncontaminated epidermal strips13 and this property has made it possible to calculate the apparent sensitivity of the stomatal complex to ABA. The evidence is based on experiments involving the uptake, distribution and metabolism of exogenous 2-14C-ABA.