Article (Scientific journals)
Dissociation of increases in plasma insulin-like growth factor I and testosterone during the onset of puberty in bulls
Renaville, Robert; Massart, Serge; Sneyers, M. et al.
1996In Journal of Reproduction and Fertility, 106 (1), p. 79-86
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Keywords :
IGF-I; IGFBP-3; Holstein calves
Abstract :
[en] The present study was conducted to examine the relationship between plasma concentrations of testosterone, insulin-like growth factor I (IGF-I) and IGF-binding proteins (IGFBPs) during puberty, in male calves treated with GnRH or testosterone propionate. Twelve male Holstein calves (10 weeks old) were assigned to the control group (n = 6), the GnRH-treated group (n = 3) or the testosterone-treated group (n = 3). For 8 weeks, the GnRH-treated group received a single i.v. injection of GnRH (0.5 mu g kg(-1) body mass) each day while the testosterone-treated group received an i.m. injection of testosterone propionate (0.5 mg kg(-1) body mass) twice a day. The calves were studied until they were 200 days old. Hormone treatments were stopped one month after puberty was reached in the control group. Blood samples were collected every 30 min for 8 h every third day. Hormone concentrations were determined by radioimmunoassay. Western ligand blotting and immunoblotting, using monoclonal antibodies against IGFBP-2, and IGFBP-3, were used to characterize the IGF-binding proteins. In the control group, puberty occurred at about 120 days of age and was associated with an increase in concentrations of testosterone, IGF-I and IGFBP-3 and a decrease in concentration of IGFBP-2. In the GnRH-treated group, plasma testosterone remained low until 8 weeks after establishment of puberty in the control group (4 weeks after the end of treatment). In the testosterone-treated group, testosterone was high during the treatment period and then decreased to prepubertal values when treatment was stopped. Testosterone values increased again to reach postpubertal values 5 weeks after the end of hormone treatment. Nevertheless, independent of testosterone status, the profile of IGF-I and the IGFBPs in the GnRH- and testosterone-treated groups were parallel to that reported for the control group with the transition from prepubertal to adult values at about 120 days of age. In conclusion, concentrations of testosterone, IGF-I and IGFBP-3 increase together, but probably independently, during the onset of puberty in male calves.
Disciplines :
Animal production & animal husbandry
Genetics & genetic processes
Author, co-author :
Renaville, Robert 
Massart, Serge
Sneyers, M.
Falaki, M.
Gengler, Nicolas  ;  Université de Liège - ULiège > Gembloux Agro-Bio Tech > Gembloux Agro-Bio Tech
Burny, Arsène ;  Université de Liège - ULiège > Agro Biotech Gembloux
Portetelle, Daniel ;  Université de Liège - ULiège > Agronomie, Bio-ingénierie et Chimie (AgroBioChem) > Microbial, food and biobased technologies
Language :
English
Title :
Dissociation of increases in plasma insulin-like growth factor I and testosterone during the onset of puberty in bulls
Publication date :
1996
Journal title :
Journal of Reproduction and Fertility
ISSN :
0022-4251
Publisher :
Portland Press, Colchester, United Kingdom
Volume :
106
Issue :
1
Pages :
79-86
Peer reviewed :
Peer Reviewed verified by ORBi
Available on ORBi :
since 08 September 2009

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