Administration of recombinant human growth hormone on alternate days is sufficient to increase whole body protein synthesis and lipolysis in growth hormone deficient adults.
OBJECTIVE
At present, the duration of the effect of recombinant human growth hormone (rhGH) on the rates of protein synthesis and lipolysis in GH deficient (GHD) adults is unknown. This study was designed to establish the frequency of rhGH administration necessary to provide the beneficial metabolic effects of the hormone in GHD adults.


METHODS
Two different studies (A and B) were performed in two groups of five GHD men. In study A, whole body protein and lipid kinetics was determined in the basal state (Bas), 12 (GH12h) and 36 (GH36h) h after the last of seven injections of rhGH (3.3 microg/kg), given at bedtime on alternate days. In study B, the same parameters were determined in the basal state (Bas), 60 (GH60h) and 84 (GH84h) h after the last of seven injections of rhGH (3.3 microg/kg), given at bedtime at 3 day intervals.


METHODS
The rates of protein metabolism were estimated by infusing [1-13C]leucine, and those of lipolysis by infusing [1,1,2,3, 3-D5]glycerol.


RESULTS
Leucine oxidation decreased (P < 0.01) by approximately 30% after GH12h and GH36h but did not change after GH60h and GH84h. Non-oxidative leucine disposal increased after GH12h and GH36h by approximately 13% (P < 0.05) whereas it did not change after GH60h and GH84h. Glycerol appearance increased (P < 0. 01) by approximately 45% after GH12h and GH36h but did not change after GH60h and GH84h.


CONCLUSIONS
The effects on protein and lipid metabolism following the injection of rhGH last longer than 36 and less than 60 h. In fact, rhGH administration on alternate days induced a sustained increase in the rates of protein synthesis and lipolysis of GHD adults, whereas a longer interval of administration (3 days) had no effect by 60 h.
Lucidi
P
P
Department of Internal Medicine, Endocrine and Metabolic Sciences, University of Perugia, Italy.
Laureti
S
S
Santoni
S
S
Lauteri
M
M
Busciantella-Ricci
N
N
Angeletti
G
G
Santeusanio
F
F
De Feo
P
P
D000328:Adult; D000704:Analysis of Variance; D001786:Blood Glucose / Q000378:metabolism; D002096:C-Peptide / Q000378:metabolism; D004334:Drug Administration Schedule; D005990:Glycerol / Q000493:pharmacokinetics; D013006:Growth Hormone / Q000008:administration & dosage* / Q000172:deficiency* / Q000627:therapeutic use; D006801:Humans; D007018:Hypopituitarism / Q000188:drug therapy* / Q000378:metabolism; D007328:Insulin / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D007930:Leucine / Q000493:pharmacokinetics; D050356:Lipid Metabolism; D008066:Lipolysis; D008297:Male; D014176:Protein Biosynthesis; D013997:Time Factors
D001786:Blood Glucose; D002096:C-Peptide; D007328:Insulin; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone; D007930:Leucine; D005990:Glycerol