A possible relationship between serum transferrin, growth hormone secretion and height velocity in children.

Since transferrin (Tf) in vitro has a growth-promoting activity and is associated with NSILA properties, the aim of this work was to study in vivo the relationships between Tf, somatomedin activity (SM), growth hormone (GH) secretion, and height velocity in children. An iv infusion of ornithine hydrochloride was given to 23 controls; the induced rise of GH was accompanied by a simultaneous fall of SM (r = -0.711, P less than 0.001) and was preceded by a fall of Tf (r = -0.610, P less than 0.01). In 17 obese children SM was within the normal range, when Tf levels were higher and arginine-induced GH peaks lower than in the controls, and a negative correlation was found between Tf basal levels and GH peaks (r = -0.608, P less than 0.01). In 9 children with confirmed hypopituitarism the Tf levels were significantly lower than in the controls. In 14 children with confirmed or suspected hypopituitarism a single im injection of hGH (6 mg) failed to induce Tf variations over 24 h. In 39 of these children the height velocity was significantly correlated with Tf basal levels (r = 0.701, P less than 0.001). These data suggest that transferrin is involved in growth regulation, and that GH secretion is related to transferrin levels by a feed-back mechanism.