Designing a long-acting human growth hormone (hGH) by fusing the carboxyl-terminal peptide of human chorionic gonadotropin beta-subunit to the coding sequence of hGH.
Chimeric genes were constructed by fusing of human GH (hGH) cDNA to one, two, or three cassettes of the carboxyl-terminal peptide (CTP) of human chorionic gonadotropin (hCG)-beta-subunit. hGH variant genes were inserted into the pCI-DHFR plasmid, transfected into DG44 cells, and stable clones were selected. Bioactivity and pharmacokinetic studies were performed in hypophysectomized Sprague Dawley derived male rats. The results indicated that sc injections of GH-wild-type (WT), Biotropin (commercial), GH-CTP, or CTP-GH (0.6 mg/kg) once every 5 d for 11 d (total dose of 1.2 mg/kg) resulted in an increased weight gain by 4, 4.9, 5.1, and 7 g, respectively. Treatment with CTP-GH-CTP-CTP (GH-LA) or CTP-GH-CTP (0.6 mg/kg) once every 5 d for 11 d or with Biotropin (0.12 mg/kg) daily for 11 d (total dose 1.2 mg/kg) resulted in a dramatic increase in weight gain of 16.5, 16.8, and 17 g, respectively. Repeated injections with different doses of GH-LA, 0.6, 1.8 mg/kg every 4 d or daily injection of 0.12 mg/kg of Biotropin increased the weight gain by 16, 28, and 18 gr, respectively. In addition, the cumulative serum levels of IGF-I after injection of GH-LA was significantly higher than that detected after injection of Biotropin. Pharmacokinetic studies indicated that the half-life, mean residence time, area under the curve, time of maximal plasma concentration, and maximal plasma concentration of GH-LA are dramatically increased compared with Biotropin. This may suggest that the mechanism of GH metabolic clearance is affected by the presence of CTP. These data establish a rationale for using this chimera as a long-acting GH analog.
Fares
Fuad
F
Department of Human Biology, Faculty of Natural Sciences, University of Haifa, and Carmel Medical Center, Haifa 31905, Israel. ffares@sci.haifa.ac.il
Guy
Rachel
R
Bar-Ilan
Ahuva
A
Felikman
Yana
Y
Fima
Eyal
E
D000818:Animals; D019540:Area Under Curve; D015153:Blotting, Western; D016466:CHO Cells; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D006224:Cricetinae; D003412:Cricetulus; D019382:Human Growth Hormone / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D007016:Hypophysectomy; D008297:Male; D008657:Metabolic Clearance Rate; D016366:Open Reading Frames / Q000235:genetics*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011993:Recombinant Fusion Proteins / Q000235:genetics* / Q000378:metabolism / Q000493:pharmacokinetics; D013997:Time Factors; D015430:Weight Gain / Q000187:drug effects
D018997:Chorionic Gonadotropin, beta Subunit, Human; D011993:Recombinant Fusion Proteins; D019382:Human Growth Hormone