Plasma half-lives of native and modified insulin-like growth factor-I in lambs.

The clearance of labelled insulin-like growth factor-I (IGF-I) has been measured in lambs following acid gel-permeation chromatography and immunoprecipitation of plasma samples. The half-lives obtained in three experiments were between 5 and 7h. Chromatography at neutral pH on a Fractogel HW55(S) column demonstrated that all the radioactivity associated with undegraded peptide in plasma was bound to a carrier protein.

Catecholamines and Ca2+ mediate an increase in activity and reactive thiols of rat heart phosphofructokinase.

Catecholamines and Ca2+ mediate an increase in reactive-thiol status of phosphofructokinase, associated with an increase in activation of the enzyme. A correlation was observed between the number of reactive thiols and activation (r = 0.878; P less than 0.

Is orally-derived epidermal growth factor beneficial following premature birth or intestinal resection?

Epidermal growth factor (EGF), a major growth factor in human milk, may stimulate growth and development of crucial infant tissues, particularly in conditions where the infant's growth is compromised. Here, we provide evidence of a role for EGF in two such conditions, premature birth and intestinal resection. Compared with women delivering at term, mothers of premature infants produce milk containing higher concentrations of EGF, an effect that is probably maintained throughout lactation.

Interference by ATPase in the assay of rat heart phosphofructokinase.

A high molecular-weight protein was found in heart extracts which, in the assay for phosphofructokinase, artificially activated the enzyme. The protein could be removed by gel-exclusion chromatography or high-speed centrifugation. The mechanism of activation appeared to be due to the hydrolysis of ATP to ADP, AMP and inorganic phosphate which was inhibited by Mn2+.

Insensitivity of cardiac phosphofructokinase to adrenergic activation in Zucker rats. A post-receptor defect.

The apparent insensitivity of phosphofructokinase to activation by adrenaline in hearts from genetically obese Zucker (fa/fa) rats [Patten, Filsell & Clark (1982) Metab. Clin. Exp.