title: Effects of parturition and feed restriction on concentrations and distribution of the insulin-like growth factor-binding proteins in plasma and cerebrospinal fluid of dairy cows.
abstract: Hormones and metabolites act as satiety signals in the brain and play an important role in the control of feed intake (FI). These signals can reach the hypothalamus and brainstem, 2 major centers of FI regulation, via the blood stream or the cerebrospinal fluid (CSF). During the early lactation period of high-yielding dairy cows, the increase of FI is often insufficient. Recently, it has been demonstrated that insulin-like growth factors (IGF) may control FI. Thus, we asked in the present study if IGF-binding proteins (IGFBP) are regulated during the periparturient period and in response to feed restriction and therefore might affect FI as well. In addition, we specifically addressed conditional distribution of IGFBP in plasma and CSF. In one experiment, 10 multiparous German Holstein dairy cows were fed ad libitum and samples of CSF and plasma were obtained before morning feeding on d -20, -10, +1, +10, +20, and +40 relative to calving. In a second experiment, 7 cows in second mid-lactation were sampled for CSF and plasma after ad libitum feeding and again after feeding 50% of the previous ad libitum intake for 4 d. Intact IGFBP-2, IGFBP-3, and IGFBP-4 were detected in plasma by quantitative Western ligand blot analysis. In CSF, we were able to predominantly identify intact IGFBP-2 and a specific IGFBP-2 fragment containing detectable binding affinities for biotinylated IGF-II. Whereas plasma concentrations of IGFBP-2 and IGFBP-4 increased during the periparturient period, IGFBP-3 was unaffected over time. In CSF, concentrations of IGFBP-2, both intact and fragmented, were not affected during the periparturient period. Plasma IGF-I continuously decreased until calving but remained at a lower concentration in early lactation than in late pregnancy. Food restriction did not affect concentrations of IGF components present in plasma or CSF. We could show that the IGFBP profiles in plasma and CSF are clearly distinct and that changes in IGFBP in plasma do not simply correspond in the brain. We thus assume independent control of IGFBP distribution between plasma and CSF. Due to the known anorexic effect of IGF-I, elevated plasma concentrations of IGFBP-2 and IGFBP-4 during the postpartum period in conjunction with reduced plasma IGF-I concentrations may be interpreted as an endocrine response against negative energy balance in early lactation in dairy cows.
authors.affiliation: Institute of Nutritional Physiology "Oskar Kellner," Leibniz Institute for Farm Animal Biology (FBN), Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Laeger
authors.affiliation: Ligandis GbR, Leibniz Institute for Farm Animal Biology (FBN), Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany; Institute of Genome Biology, Leibniz Institute for Farm Animal Biology (FBN), Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Wirthgen
authors.affiliation: Endocrinology Laboratory, Clinic for Cattle, University of Veterinary Medicine Foundation, Bischofsholer Damm 15, 30173 Hannover, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Piechotta
authors.affiliation: F. Hoffmann-La Roche Ltd., pRED, Pharma Research & Early Development, Neuroscience DTA, Grenzacherstrasse 124, 4070 Basel, Switzerland.
authors.forename: F
authors.initials: F
authors.lastname: Metzger
authors.affiliation: Institute of Nutritional Physiology "Oskar Kellner," Leibniz Institute for Farm Animal Biology (FBN), Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany.
authors.forename: C C
authors.initials: CC
authors.lastname: Metges
authors.affiliation: Institute of Nutritional Physiology "Oskar Kellner," Leibniz Institute for Farm Animal Biology (FBN), Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany. Electronic address: b.kuhla@fbn-dummerstorf.de.
authors.forename: B
authors.initials: B
authors.lastname: Kuhla
authors.affiliation: Ligandis GbR, Leibniz Institute for Farm Animal Biology (FBN), Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany; Institute of Genome Biology, Leibniz Institute for Farm Animal Biology (FBN), Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany. Electronic address: hoeflich@fbn-dummerstorf.de.
authors.forename: A
authors.initials: A
authors.lastname: Hoeflich
mesh_terms: D000818:Animals; D002417:Cattle / Q000502:physiology*; D004703:Endocrine System / Q000378:metabolism; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D005508:Food Deprivation / Q000502:physiology*; D005786:Gene Expression Regulation; D018969:Insulin-Like Growth Factor Binding Proteins / Q000097:blood* / Q000134:cerebrospinal fluid / Q000378:metabolism; D007774:Lactation / Q000502:physiology*; D036801:Parturition; D049590:Postpartum Period; D011247:Pregnancy; D013002:Somatomedins
chemical_list: D018969:Insulin-Like Growth Factor Binding Proteins; D013002:Somatomedins
keywords: cerebrospinal fluid; feed restriction; insulin-like growth factor; insulin-like growth factor binding proteins; transition period