Thyroxine (T4), triiodothyronine (T3) and thyroxine-binding globulin (TBG) were determined in healthy individuals ranging in age from newborn to 95 years. T4: 10.25 +/- 1.62 microng/100 ml, T3: 1.62 +/- 0.35 ng/ml and TBG: 1.34 +/- 0.15 mg/100 ml, were found elevated until puberty compared to a middle age group with T4: 7.27 +/- 2.26 microng/100 ml, T3: 1.15 +/- 0.24 ng/ml and TBG: 0.98 +/- 14 mg/100 ml. T4 and T3 followed almost TBG concentration. In old age is dissociation between T4: 5.79 +/- 1.56 microng/100 ml, T3: 0.79 +/- 0.21 ng/ml and TBG: 1.28 +/- 0.15 mg/100 ml was found. Except for old age the ratio T4/TBG and T3/TBG minimized the age dependent variation of T4 and T3 and reduced the coefficient of variance from 26% to 17.7% for T4 and from 26.5 to 25% for T3. Age reduction of T4/TBG is 15% and of T3/TBG 13% respectively more pronounced than for T4 and T3 alone. These data indicate: 1) age related variations of T4 and T3 due to age dependency of TBG, 2) deviation of T4 and T3 values in old age from that expected by their TBG levels and 3) the importance of the routine use of hormone/TBG ratio.

Hypercalcaemia frequently complicates the clinical management of cancer. Many factors have been implicated in the pathogenesis of this humoral hypercalcaemia of malignancy, the most recent candidate being parathyroid hormone-related peptide (PTHrP). Until now, this peptide has been detected only in some normal and transformed adult tissues. In recent years, it has become apparent that tumours are capable of expressing and secreting factors previously elaborated only during fetal life. Many of these factors act to stimulate the growth of both tumour and fetal cells in an autocrine manner. The data presented here demonstrate that PTHrP is expressed in the human and rat fetus throughout gestation. Immunocytochemistry reveals a gestationally related, changing pattern of expression which is paralleled by changes in mRNA transcription. These data support the hypothesis that PTHrP may function as a fetal growth factor.

No abstract

No abstract