We prospectively investigated urinary iodine concentration (UIC) in pregnant women and in female, non-pregnant controls in the canton of Berne, Switzerland, in 1992. Mean UIC of pregnant women [205 +/- 151 microg iodine/g creatinine (microg l/g Cr); no. = 153] steadily decreased from the first (236 +/- 180 microg l/g Cr; no. = 31) to the third trimester (183 +/- 111 microg l/g Cr, p < 0.0001; no. = 66) and differed significantly from that of the control group (91 +/- 37 microg l/g Cr, p < 0.0001; no. = 119). UIC increased 2.6-fold from levels indicating mild iodine deficiency in controls to the first trimester, demonstrating that high UIC during early gestation does not necessarily reflect a sufficient iodine supply to the overall population. Pregnancy is accompanied by important alterations in the regulation of thyroid function and iodine metabolism. Increased renal iodine clearance during pregnancy may explain increased UIC during early gestation, whereas increased thyroidal iodine clearance as well as the iodine shift from the maternal circulation to the growing fetal-placental unit, which both tend to lower the circulating serum levels of inorganic iodide, probably are the causes of the continuous decrease of UIC over the course of pregnancy. Mean UIC in our control group, as well as in one parallel and several consecutive investigations in the same region in the 1990s, was found to be below the actually recommended threshold, indicating a new tendency towards mild to moderate iodine deficiency. As salt is the main source of dietary iodine in Switzerland, its iodine concentration was therefore increased nationwide in 1998 for the fourth time, following increases in 1922, 1965 and 1980.

In the Bernese region, where goiter was formerly endemic, alimentary salt has been supplemented by increasing amounts of potassium iodide (KI): 5, 10, 20 mg KI/kg in 1922, 1965 and 1980 respectively. Ioduria rose from < 30 micrograms I/g creatinine in 1920 to > 100 micrograms I/g creatinine in the 1980s. In 1992 ioduria was estimated in 55 healthy volunteers (group A and individual B) and 234 thyroid carcinoma patients after thyroidectomy: hypothyroid patients with (C) and without thyroid remnants (D) and euthyroid patients on T4 substitution (E). The arithmetic mean iodine excretion of the healthy volunteers in group A and individual B was found to be 87 +/- 40 micrograms I/g creatinine. This is insufficient according to the recommendations of the WHO. In all groups, the iodine excretion reached the recommended level only in some members: 24% (A, B), 19% (C), 38% (D) and 81% (E). It was thought in the 1980s that in a formerly iodine-deficient society, iodinated salt would continue to provide an adequate supply of iodine. However, iodine intake in this affluent society has proved to be unstable. This can be attributed to modifications of eating habits, which include a reduction of total salt consumption, combined with a growing consumption of manufactured food of cosmopolitan origin, prepared using salt containing little or no iodine.

No abstract

Pregnancy-associated plasma protein-A (PAPP-A) was detected by RIA in human seminal plasma. This was not due to interference with proteases or binding to seminal plasma proteins, since immunoreactivity was not affected by treatment with protease inhibitors, and the elution of [125I]PAPP-A was not altered by preincubation with seminal plasma. The major component of the seminal plasma PAPP-A coeluted with pure PAPP-A or plasma PAPP-A from pregnant and nonpregnant women. In the RIA, serial dilutions of seminal plasma gave parallel displacement curves to pregnancy plasma. Removing PAPP-A-like material from seminal plasma by adsorbtion to heparin-Sepharose reduced the inhibitory effect of seminal plasma on phytohemagglutinin-induced lymphocyte transformation. The source of seminal plasma PAPP-A-like immunoreactive material remains to be elucidated, but it is unlikely to be the testis, since PAPP-A levels in semen of vasectomized men were similar to those in nonvasectomized men.