Changes in plasma concentrations of insulin-like peptide 3 and testosterone from birth to pubertal age in beef bulls

• Published in: Theriogenology Vol. 76; no. 9; pp. 1632 - 1638
• Main Authors: Kawate, N, Ohnari, A, Pathirana, I.N, Sakase, M, Büllesbach, E.E, Takahashi, M, Inaba, T, Tamada, H
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-12-2011
• Subjects: Age Factors; Animals; Beef bull; beef bulls; calves; Cattle - blood; Cattle - growth & development; Enzyme immunoassay; enzyme immunoassays; Immunoenzyme Techniques; Insulin - blood; luteinizing hormone; Luteinizing Hormone - blood; Male; parturition; Plasma INSL3 (RLF) concentration; Proteins; Puberty; Sexual Maturation; Testosterone; Testosterone - blood; Testosterone; Puberty; Plasma INSL3 (RLF) concentration; LH; Enzyme immunoassay; Beef bull
• ISSN: 0093-691X; 1879-3231
• DOI: 10.1016/j.theriogenology.2011.07.011

The objectives were to: (1) develop an enzyme immunoassay (EIA) for insulin-like peptide 3 (INSL3) or relaxin-like factor (RLF) in bovine plasma; (2) investigate changes of plasma INSL3 concentrations from birth to pubertal age of beef bulls; and (3) compare changes in plasma concentrations of INSL3, testosterone, and LH. Plasma samples were collected from beef bull calves (n = 15) at birth (0 d) and at 28, 56, and 84 d after birth. Furthermore, in beef bulls around pubertal age (n = 26; age range 3 to 22 mo), plasma samples were collected at 1 to 4 mo intervals. Plasma INSL3 concentrations increased (P < 0.05) from 0 to 28, 28 to 56, and from 56 to 84 d of age. Plasma testosterone concentrations increased (P < 0.001) from 0 to 28 d, and from 28 to 56 d, but did not change from 56 to 84 d. For bulls around pubertal age, plasma INSL3 concentrations did not change from the prepubertal phase (3 to 6 mo) to the early pubertal phase (6 to 12 mo), but increased (P < 0.05) from the early to late pubertal phases (12 to 18 mo), and from the late pubertal to postpubertal phases (18 to 22 mo). Plasma testosterone concentrations increased from the prepubertal to early pubertal phases (P < 0.001), but did not change thereafter. Plasma LH concentrations did not change from 0 d to 84 d, but decreased (P < 0.001) from prepubertal to early pubertal phase, with no significant change thereafter. Plasma INSL3 concentrations increased during the first 3 mo of life and throughout the pubertal age in beef bulls. There were similar dynamic patterns for INSL3 and testosterone during the first 3 mo of life, but patterns subsequently diverged in bulls around pubertal ages.