Development of a radioimmunoassay for plasma C-peptide in sheep: kinetics of C-peptide and effects of exogenous growth hormone and glucose on insulin and C-peptide.
An antiserum to purified bovine C-peptide was used to develop a sensitive radioimmunoassay for C-peptide in sheep. The assay was used to measure kinetics of C-peptide and insulin in non-pregnant and non-lactating sheep. Injected, purified C-peptide was distributed in pools comprising c. 11.4% of liveweight, the half time of C-peptide was estimated as 13.7 min and its clearance rate was c. 5 ml kg-1 min-1. In lactating ewes exogenous recombinant bovine growth hormone (rebGH) increased both plasma insulin and C-peptide as did glucose challenge given before and during administration of rebGH. Estimates of insulin secretion rate in lactating ewes were c. 7 x 10(-3) and 8.5 x 10(-3) nmol kg-1 min-1 before and after glucose challenge prior to injections of rebGH. After 4 days of injection of rebGH, corresponding values were c. 8 x 10(-3) and 10 x 10(-3) nmol min-1 kg-1.
Leenanuruksa
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Department of Animal Husbandry, University of Sydney, Camden, N.S.W.
McDowell
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D000818:Animals; D002096:C-Peptide / Q000097:blood* / Q000493:pharmacokinetics; D005260:Female; D005947:Glucose / Q000494:pharmacology*; D013006:Growth Hormone / Q000494:pharmacology*; D007328:Insulin / Q000097:blood*; D007700:Kinetics; D007774:Lactation / Q000502:physiology; D008657:Metabolic Clearance Rate; D011247:Pregnancy; D011863:Radioimmunoassay; D011994:Recombinant Proteins; D012756:Sheep / Q000097:blood*
D002096:C-Peptide; D007328:Insulin; D011994:Recombinant Proteins; D013006:Growth Hormone; D005947:Glucose