Plasma transferrin levels in abnormal endocrine states. II. The changes in various endocrine states

The clinical significance of the measurement of plasma transferrin (Tf) in patients with hypophysial disorders was reported in our previous paper. In the present study, we determined plasma Tf levels in 55 patients with various endocrine states and considered their clinical significance compared with plasma somatomedin-C (SM-C) levels. Plasma Tf levels decreased significantly in patients with anorexia nervosa (P less than 0.02), hyperthyroidism (P less than 0.05), primary hypothyroidism (P less than 0.05), and Cushing's syndrome (P less than 0.05), while they were elevated significantly in pregnancy (P less than 0.01) or females using estrogens (P less than 0.05). The former two declines were considered a reflection of the malnutritional state since a significant negative correlation was observed between plasma Tf levels and the percentile deficit from the ideal body weight in patients with anorexia nervosa (P less than 0.01), or between plasma Tf and elevated T3 levels which induce hypermetabolism in patients with hyperthyroidism (P less than 0.01). A significant correlation was observed between the SM-C and Tf levels in these subjects (including normal controls and patients with hypophysial disorders) as a whole (r = 0.79, P less than 0.001). These data indicate that plasma Tf is changeable according to the endocrine and nutritional conditions with good correlation to the SM-C, and it is suggested that Tf also operates as a growth factor in vivo.