Hypertrophy and hyperplasia of bovine fetal tissues during development: fetal liver insulin-like growth factor I mRNA expression.

Tissue growth of crossbred fetal beef calves was examined by measuring RNA, DNA, and protein concentrations in liver, heart, and biceps femoris. Furthermore, liver insulin-like growth factor I (IGF-I) mRNA expression and mRNA species size during fetal development was observed. Tissue samples were collected from six fetuses every 42 d of gestation, from d 106 to d 274.

Growth performance and carcass composition of lambs infused for 28 days with a growth hormone-releasing factor analogue.

A human growth hormone-releasing factor analogue, [DesNH2Tyr1,D-Ala2,Ala15]hGRF(1-29)NH2 (GRF-A), was infused s.c. into lambs for 28 d to determine its effects on growth performance and carcass composition.

Cloning of ovine insulin-like growth factor-I cDNAs: heterogeneity in the mRNA population.

We have isolated and characterized lamb liver cDNAs encoding ovine insulin-like growth factor-I (oIGF-I) precursor polypeptide to study IGF-I gene expression in ruminants. Four cDNA clones were sequenced revealing two different exon 1 sequences (designated 1A and 1B) and four different putative poly(A) adenylation sites. cDNAs containing exon 1A or exon 1B encode precursor polypeptides of 138 or 154 amino acids, respectively.

Use of osmotic pumps for subcutaneous infusion of growth hormone-releasing factors in steers and wethers.

Osmotic pumps were evaluated for 7-d delivery of growth hormone-releasing factor (GRF). In Exp. 1, 12 steers weighing 253 kg received hGRF(1-29)NH2 in H2O at rates of 0, 3, 30 and 300 pmol.