Circulating growth hormone and insulin-like growth factor-I in nonalcoholic liver cirrhosis with or without superimposed hepatocarcinoma: evidence of an altered circadian rhythm.
Adult liver is considered the major source of circulating insulin-like growth factor-I (IGF-I). Growth hormone (GH) exerts its effects by stimulating IGF-I release from the liver, which then mediates the somatogenic actions in target tissues. In turn, circulating IGF-I levels operate a negative feedback mechanism on GH release. In cirrhotic patients, single daily determinations, performed after an overnight fast, indicated that serum IGF-I are decreased, whereas GH levels are increased. To verify whether this phenomenon occurs through the 24-h period, we have studied the profiles of GH and IGF-I in cirrhotic patients with or without superimposed hepatocellular carcinoma (HCC) and in a group of control subjects. The results of the present studies suggest that in cirrhotic patients, the above changes are constantly present through the 24-h period, and are associated with a loss of circadian rhythm for both GH and IGF-I. These data are consistent with a failure of the liver to synthesize and release IGF-I in response to GH. In addition, the presence of constantly higher IGF-I levels in cirrhotic patients with superimposed HCC, compared with cirrhotic patients without HCC, raises the hypothesis of a causal relationship between IGF-I and the development of HCC.
Buzzelli
G
G
Dipartimento di Fisiopatologia Clinica-Unitá di Medicina Nucleare and Fisica Medica, Universitá di Firenze, Italy.
Dattolo
P
P
Pinzani
M
M
Brocchi
A
A
Romano
S
S
Gentilini
P
P
D000328:Adult; D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000097:blood* / Q000150:complications; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D013006:Growth Hormone / Q000097:blood*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008103:Liver Cirrhosis / Q000097:blood* / Q000150:complications; D008113:Liver Neoplasms / Q000097:blood* / Q000150:complications; D008297:Male; D008875:Middle Aged
D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone