Changes in serum somatotropin, somatotropin mRNA, and serum and follicular insulin-like growth factor-I in response to feed restriction in cows actively immunized against growth hormone-releasing factor

• Published in: Journal of animal science Vol. 71; no. 11; pp. 3033 - 3042
• Main Authors: Kirby, C.J, Armstrong, J.D, Huff, B.G, Stanko, R.L, Harvey, R.W, Heimer, E.P, Campbell, R.M
• Format: Journal Article
• Language: English
• Published: United States Am Soc Animal Sci 01-11-1993; Oxford University Press
• Subjects: ACIDE GRAS; ACIDOS GRASOS; ALIMENTACION RACIONADA; ALIMENTATION RATIONNEE; Animals; ARN MENSAJERO; ARN MESSAGER; Blotting, Northern; BOVIN DE BOUCHERIE; Cattle; Cattle - metabolism; DESARROLLO EMBRIONARIO; DEVELOPPEMENT EMBRYONNAIRE; Diet; Estradiol - blood; ESTROGENOS; Fatty Acids, Nonesterified - blood; Female; Follicular Fluid - chemistry; Food Deprivation - physiology; GANADO DE CARNE; Growth Hormone - blood; Growth Hormone - genetics; Growth Hormone-Releasing Hormone - immunology; HORMONAS; HORMONE; Hormones; IMMUNISATION; Immunization - veterinary; Immunization, Secondary - veterinary; INMUNIZACION; Insulin-Like Growth Factor I - analysis; INSULINA; INSULINE; LIQUIDE BIOLOGIQUE; LIQUIDOS CORPORALES; Luteinizing Hormone - blood; OESTROGENE; Pituitary Gland - chemistry; PLASMA SANGUIN; PLASMA SANGUINEO; Ribonucleic acid; RNA; RNA, Messenger - analysis; SERUM SANGUIN; SOMATOTROPINA; SOMATOTROPINE; SUERO SANGUINEO; VACA; VACHE
• ISSN: 0021-8812; 1525-3163
• DOI: 10.2527/1993.71113033x

Cyclic cows immunized against growth hormone-releasing factor (GRFi, n = 19), human serum albumin (HSAi, n = 10), or not immunized (CON, n = 18) were used to investigate the effects of feed restriction on serum and pituitary somatotropin (ST), pituitary ST mRNA, and serum and follicular IGF-I. Cows were either fed 2.7 kg/d cottonseed hulls (R) or given ad libitum access to feed (AL) for 15 d. Ovaries bearing the largest follicle and pituitaries were collected on d 14, at 44 to 45 h after injection of prostaglandin F2 alpha. Data from CON and HSAi cows were similar; thus, data were combined (represented as CON). Serum ST (nanograms/milliliter) on d 13 was greater (P 0.09) in CON-R (5.3) than in CON-AL (3.9), whereas ST in GRFi-AL (1.1) and GRFi-R (1.1; pooled SE