Machiko Endo

Transient Hypothyroidism in Infants due to Maternal TSH-Receptor Blocking Antibodies-Character of Their IgG and Long-Term Prognosis of Their Infants

Transient neonatal hypothyroidism in infants born to mothers with chronic thyroidism, first reported in 1960 by Sutherland et al.l), has been established as an important diseases entity in the newborn period. Transplacental transfer of TSH-receptor blocking antibodies has been defined as the cause of the disease.) Although similar cases have been reported since then,3) 4) the clinical features, as well as the prognosis of each case, varied greatly. That is, most of infants developed normally; however, some infants were physically, mentally or emotionally retarded in spite of intensive treatment during the newborn period,1) and their condition was quite different from that found in congenital hypothyroidism. It is not clear whether the difference was due to the nature of TSH-receptor blocking antibodies in the mother or to the severity of thyroid suppression during the fetal and newborn periods. It was suggested that the IgG in the mother’s serum not only inhibited TSH binding to its receptor, but also blocked TSH-stimulated cAMP response, TSH-stimulated iodine uptake, organification and 3H-thymidine incorporation into DNA in cultured thyroid cells: that is, it blocked post-receptor processes.4) The purposes of this paper are twofold: 1) To study more precise mechanism and to evaluate the possible involvement of GTP-binding protein of the inhibition of adenylate cyclase activities using porcine thyroid cells. 2) To establish a basis for the long-term prognosis of these patients, particularly of two of the sibling sets, whose mothers were once hypothyroid and were euthyroid during pregnancy.

Prolactin response to thyrotropin-releasing hormone in children with Turner's syndrome and hyperthyroidism

Plasma prolactin (PRL) response to synthetic thyrotropin-releasing hormone (TRH) was studied in 26 prepubertal and 19 pubertal children with constitutional short stature, 7 patients with Turners syndrome and 10 patients with hyperthyroidism. The mean basal concentrations of plasma PRL did not differ among groups. In prepubertal children PRL responses to TRH were comparable in both sexes, while pubertal children plasma PRL levels after TRH in females were significantly higher (P<0.05) than those in age-matched males. Plasma PRL levels after TRH in patients with Turners syndrome were significantly higher (P<0.05) than those in age-matched males, but were not significantly different from those in age-matched females. Plasma PRL response to TRH was markedly suppressed in patients with hyperthyroidism before treatment, but it returned to normal after treatment when patients became euthyroid. A significant correlation (P<0.05) between peak concentrations of plasma PRL after TRH stimulation and plasma T3 but not T4 levels was observed.These data suggest that a sex difference in TRH-stimulated PRL secretion appears around puberty and that plasma PRL response to TRH is suppressed in children with hyperthyroidism. The magnitude of plasma PRL response to TRH is closely correlated with the severity of hyperthyroidism when judged by plasma T3 but not T4 concentrations.

Effect of changes in basal metabolic rate on the circadian rhythm of human body temperature

Abstract In order to investigate whether changes in basal metabolic rate (BMR) influence the basic 24‐h rhythm of body temperature we examined daily variations of body temperature in eight hyperthyroid patients and two patients with anorexia nervosa. Although they exhibited high and low BMR, respectively, they demonstrated the temperature rhythm patterns similar to those in healthy control. These results suggest that both an increased and a decreased BMR may not modify the circadian rhythm of human body temperature.