Effects of somatotropin on the conceptus, uterus, and ovary during maternal recognition of pregnancy in cattle

• Published in: Domestic animal endocrinology 1995, Vol.12 (1), p.73-82
• Main Authors: Lucy, M.C., Thatcher, W.W., Collier, R.J., Simmen, F.A., Ko, Y., Savio, J.D., Badinga, L.
• Format: Article
• Language: English
• Subjects: Animals; BINDING PROTEINS; BODY FLUIDS; Carrier Proteins - analysis; Carrier Proteins - blood; Cattle - metabolism; Cattle - physiology; CORPS JAUNE; CORPUS LUTEUM; Corpus Luteum - chemistry; Corpus Luteum - drug effects; Corpus Luteum - physiology; COWS; CUERPO LUTEO; Estradiol - analysis; Estradiol - blood; ESTROGENOS; FACTEUR DE CROISSANCE IGF; FACTOR DE CRECIMIENTO IGF; Female; Fetus - drug effects; Fetus - physiology; FOLLICULAR FLUID; Follicular Fluid - chemistry; Follicular Fluid - metabolism; GESTACION; GESTATION; GRAAFIAN FOLLICLES; Growth Hormone - pharmacology; HORMONE RECEPTORS; INSULIN-LIKE GROWTH FACTOR; Insulin-Like Growth Factor Binding Proteins; Insulin-Like Growth Factor I - analysis; Lactation - physiology; LIQUIDE BIOLOGIQUE; LIQUIDOS CORPORALES; OESTROGENE; OESTROGENS; OVAIRE; Ovarian Follicle - cytology; Ovarian Follicle - drug effects; Ovarian Follicle - metabolism; OVARIES; OVARIOS; Ovary - chemistry; Ovary - drug effects; Ovary - physiology; PREGNANCY; Pregnancy, Animal - physiology; PROGESTERONA; PROGESTERONE; Progesterone - analysis; Progesterone - blood; PROTEINAS AGLUTINANTES; PROTEINE DE LIAISON; RECEPTEUR D'HORMONE; RECEPTORES DE HORMONAS; Recombinant Proteins - pharmacology; SOMATOTROPIN; SOMATOTROPINA; SOMATOTROPINE; UTERO; UTERUS; Uterus - chemistry; Uterus - drug effects; Uterus - physiology; VACA; VACHE
• ISSN: 0739-7240; 1879-0054
• DOI: 10.1016/0739-7240(94)00010-X

Effects of recombinant bovine somatotropin (rbST) on ovarian and uterine function and the production of components of the insulin-like growth factor (IGF) system were examined during the period of maternal recognition of pregnancy in cattle. Lactating dairy cows were treated with 25 mg/d rbST (n = 8) or saline (n = 8) for 16 d after estrus. Ovaries, uteri, and conceptuses were collected on Day 17 after estrus. The length (millimeters) of the conceptus was recorded. The concentration of IGF-I and the content of IGF-binding proteins (BP) in uterine flushings were determined. Corpora lutea (CL) were weighed, and the number of follicles (⩾2 mm in diameter) were counted. Follicular fluid from the largest and second-largest follicles was assayed for the concentration of IGF-I, IGFBP, progesterone, and estradiol. The length of the conceptus and the total amount of IGF-I in uterine fluid were similar for rbST and control. Recombinant bST increased 1) the weight of the CL, 2) the number of largest follicles (10 to 15 mm in diameter), 3) the concentration of IGF-I in the follicular fluid, 4) the follicular fluid content of IGFBP of the largest estrogenic follicle, and 5) the quantity of IGFBP in uterine flushings. The concentration of progesterone in the follicular fluid tended to be increased in rbST-treated cows, whereas the concentration of estradiol was similar to that of control cows. The concentration of progesterone in plasma was similar for rbST compared with control. In conclusion, the administration of rbST in lactating dairy cows for 16 d after estrus did not alter the growth of the conceptus collected on Day 17. The greatest responses to rbST were found within the ovary, where rbST increased the weight of the CL and altered the amount of IGF-I and IGFBP in the follicular fluid.