No abstract

Oxytocin (OT) administration has been shown to inhibit adrenocorticotropic hormone (ACTH)/cortisol secretion in several experimental conditions. In the present study, the plasma OT responses to suckling in 7 lactating women or to mechanical breast stimulation in 6 normally menstruating women (experimental tests) or to sham stimuli in the same subjects (control tests) were measured and correlated with the simultaneous changes in plasma ACTH/cortisol levels. All women showed similar basal levels of OT, ACTH and cortisol, which remained unmodified after sham stimulation. In contrast, both suckling and breast stimulation produced a significant increase in plasma OT levels and a significant decrease in plasma ACTH concentrations. When OT and ACTH data were considered together, a significant negative correlation was found between the OT increase and the simultaneous ACTH decline. Plasma cortisol levels were lower during suckling or breast stimulation than in control conditions. These data show an inverse relationship between plasma OT and ACTH levels during suckling and breast stimulation in humans, suggesting an inhibitory influence of OT on ACTH/cortisol secretion in a physiological condition.

Evaluation of thyroid status by measurement of free thyroid hormone concentrations seems particularly helpful in conditions with altered serum binding proteins. In pregnancy, a condition of increased thyroxine binding globulin, serum free thyroxine (FT4) and free triiodothyronine (FT3) concentrations have been reported to be normal, increased or decreased. In the present study we have measured serum total and free thyroid hormone concentrations in pregnant women, their newborns and nonpregnant women. Serum FT4 and FT3 concentrations have been measured with 10 different commercially available kits and the results obtained have been compared. Serum total thyroid hormone concentrations in pregnant women were significantly higher than in their newborns and in nonpregnant women. Maternal serum FT4 concentrations measured with the different kits were always significantly lower than values in nonpregnant women. Furthermore, with one kit, the mean maternal serum FT4 concentration was below the normal range and with many kits, a large number of maternal serum samples had serum FT4 concentrations below the normal range. With all kits, except two, neonatal serum FT4 concentrations were higher than values in their respective mothers and, in general, lower than values in nonpregnant women. Serum FT3 concentrations in nonpregnant women were in the normal range, except with one kit, in which the mean serum FT3 concentration was below the normal range. Serum FT3 concentrations in newborns resulted markedly lower than in parturient and in non pregnant women. With almost all kits, serum FT3 values were below the normal range in many maternal samples. With one kit, maternal serum FT3 concentrations resulted higher than in nonpregnant women, whereas with the other kits serum FT3 concentrations were lower.(ABSTRACT TRUNCATED AT 250 WORDS)

We have evaluated three regimens for the rapid control (10 days' therapy) of thyrotoxicosis in hyperthyroid Graves' disease: methimazole (MMI, 40 mg/day), MMI and sodium ipodate (MMI + Na Ipodate, 1 g/day and MMI and saturated solution of potassium iodide (MMI + SSKI, 6 drops twice daily). When serum T4 and T3 concentrations were analysed as the percent change from pre-treatment values, the following results were observed. Serum T4 concentration decreased in the three treatment groups and the decrease was similar in the MMI and MMI + SSKI groups but significantly lower than in the MMI + Na ipodate group. The serum T3 concentration decreased to the normal range in all seven MMI + Na Ipodate treated patients by the fourth day of treatment and the per cent decrease in serum T3 from pre-treatment values was significantly greater than in the MMI and MMI + SSKI treated patients. The decrease in serum T3 was similar in the latter two groups. Heart rate decreased in all three groups, but the decrease was significantly more in the MMI + Na Ipodate-treated patients. The present findings suggest that the rapid control of hyperthyroid Graves' disease is similar in patients treated with MMI and MMI + SSKI and that the combination of MMI + Na Ipodate is more efficacious since the decrease in serum T3 concentrations and heart rate was significantly greater in the MMI + Na ipodate-treated patients.