Horm Metab Res 1991; 23(11): 530-534
DOI: 10.1055/s-2007-1003747
Originals Basic

© Georg Thieme Verlag, Stuttgart · New York

Effect of Human Growth Hormone-Releasing Factor and a Potent Analog on Antibody Formation in African Green Monkeys

T. F. Mowles1 , P. Stricker1 , A. M. Felix2 , K. F. Soike3 , R. M. Campbell1
  • 1Departments of Animal Science, Hoffmann-La Roche, Inc., Nutley, New Jersey
  • 2Peptide Research, Hoffmann-La Roche, Inc., Nutley, New Jersey
  • 3Tulane Delta Regional Primate Center, Covington, Louisiana, U. S. A.
Further Information

Publication History

1990

1991

Publication Date:
14 March 2008 (online)

Summary

African Green monkeys were injected (2 × daily subcutaneously for six months) with human GRF(1-44)-NH2 (10 μg/kg BW) or a more potent analog, [desNH2Tyr1, Ala15]-hGRF (l-29)-NH2 (2 μg/kg BW) to determine the potential of each peptide to induce antibody formation. Blood samples were taken every two weeks, diluted 1:100 and tested for ability to bind radioiodinated hGRF. One animal in the hGRF(1-4)-NH2 group [N = 6] produced low-titer GRF antibodies by 6 weeks (19% binding) and continued throughout the 24 weeks of treatment (average = 50-60% binding). Similarly, one animal in the hGRF analog group [N = 6] displayed low-titer GRF antibodies by 18 weeks (14% binding), with the highest binding observed at 24 weeks (51% binding). Subsequent dilutions (1:1,000 and 1:3,000) of these bleedings confirmed that higher GRF antibody titers were not masked by antibody excess. Dialyzed sera from these two animals did not affect the abilities of hGRF(1-44)-NH2 or [desNH2Tyr1, Ala15]-hGRF(1-29)-NH2 to stimulate GH secretion by rat pituitary cells in vitro. After 20 weeks of treatment, significant GH responses (increased mean GH area under the curve 2.3-2.5 fold and GH peak 3.5-3.7 fold, that of control) were observed following hGRF or hGRF analog injection. Therefore, the low titer GRF antibodies detected in monkey sera during six months of treatment with hGRF or a potent analog were biologically non-neutralizing.