Insulin-like growth factor I in the dog: a study in different dog breeds and in dogs with growth hormone elevation.
A radioimmunoassay (RIA) devised for the measurement of human insulin-like growth factor I (IGF I) was employed for the measurement of canine IGF I. Canine IGF I was extracted from plasma specimens by gel chromatography. Columns were eluted with 1 M acetic acid and the fractions representing the 55 to 85% bed volume were pooled, lyophilized and reconstituted with assay buffer. Serial dilutions of canine IGF I from both normal and acromegalic dogs when added to the RIA system gave a similar displacement pattern of human [125I]IGF I as the one obtained by the addition of unlabelled human IGF I. The dose-response curve obtained by canine IGF I paralleled the one obtained by human IGF I. Logit-log transformation and least squares fitting resulted in straight line fitting of the standard curve between 0.039 and 5 ng IGF I added per tube. The within-assay coefficient of variation (CV) was 16.7% and the between-assay CV was 21.8%. Plasma IGF I concentrations in normal dogs appeared to be a function of body size. The concentrations were 36 +/- 27 ng/ml in Cocker Spaniels, 87 +/- 33 ng/ml in Beagles, 117 +/- 34 ng/ml in Keeshonds, and 280 +/- 23 ng/ml in German Shepherds (mean +/- SEM). The mean IGF I level in a group of dogs with growth hormone (GH) elevation was 700 +/- 90 ng/ml. Though this group of dogs comprised both small and large dogs, the mean IGF I level significantly differed from the one found in German Shepherds, the largest breed studied (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
D000172:Acromegaly / Q000097:blood / Q000662:veterinary; D000818:Animals; D002850:Chromatography, Gel; D003920:Diabetes Mellitus / Q000097:blood / Q000662:veterinary; D004283:Dog Diseases / Q000097:blood; D004285:Dogs / Q000097:blood*; D013006:Growth Hormone / Q000097:blood*; D007328:Insulin / Q000097:blood*; D010455:Peptides / Q000097:blood*; D011863:Radioimmunoassay; D013002:Somatomedins / Q000097:blood*; D013045:Species Specificity
D007328:Insulin; D010455:Peptides; D013002:Somatomedins; D013006:Growth Hormone