Effects of dexamethasone and colostrum intake on the somatotropic axis in neonatal calves.
Glucocorticoids and colostrum feeding influence postnatal maturation of the somatotropic axis. We have tested the hypothesis that dexamethasone (Dexa) affects the somatotropic axis in neonatal calves dependent on colostrum intake. Calves were fed either with colostrum or with a milk-based formula (n = 14/group), and, in each feeding group, one-half of the calves were treated with Dexa (30 micro g. kg body wt-1. day-1). Pre- and postprandial blood samples were taken on days 1, 2, 4, and 5, and liver samples were taken on day 5 of life. Dexa increased insulin-like growth factor (IGF)-I, but decreased growth hormone (GH) and IGF-binding protein (IGFBP)-1 and -2 plasma concentrations and increased GH receptor (GHR) mRNA levels in liver. Dexa increased IGF-I mRNA levels only in formula-fed calves and increased hepatic GHR binding capacity, but only in colostrum-fed calves. Colostrum feeding decreased IGFBP-1 and -2 plasma concentrations and hepatic IGFBP-2 and -3 mRNA levels. In conclusion, Dexa and colostrum feeding promoted maturation of the somatotropic axis. Dexa effects partly depended on whether colostrum was fed or not.
Sauter
Stephanie N
SN
Div. of Animal Nutrition and Physiology, Univ. of Berne, Route de la Tioleyre 4, CH-1725 Posieux, Switzerland.
Ontsouka
Edgar
E
Roffler
Bettina
B
Zbinden
Yolande
Y
Philipona
Chantal
C
Pfaffl
Michael
M
Breier
Bernhard H
BH
Blum
Jürg W
JW
Hammon
Harald M
HM
D000375:Aging; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D001835:Body Weight; D002417:Cattle / Q000254:growth & development / Q000502:physiology*; D003126:Colostrum; D003907:Dexamethasone / Q000494:pharmacology*; D004435:Eating; D005938:Glucocorticoids / Q000494:pharmacology*; D013006:Growth Hormone / Q000097:blood / Q000502:physiology*; D006304:Health Status; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000097:blood; D018971:Insulin-Like Growth Factor Binding Protein 2 / Q000097:blood / Q000235:genetics; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000235:genetics; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D008099:Liver / Q000737:chemistry; D008892:Milk; D012333:RNA, Messenger / Q000032:analysis; D011986:Receptors, Somatotropin / Q000235:genetics
D005938:Glucocorticoids; D018970:Insulin-Like Growth Factor Binding Protein 1; D018971:Insulin-Like Growth Factor Binding Protein 2; D018972:Insulin-Like Growth Factor Binding Protein 3; D012333:RNA, Messenger; D011986:Receptors, Somatotropin; D007334:Insulin-Like Growth Factor I; D003907:Dexamethasone; D013006:Growth Hormone