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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1991-9-19
pubmed:abstractText
Four miniature Brahman calves born in 1988 and 1989, along with four contemporary sex-matched Brahman control calves, were used in experiments to determine circulating concentrations of insulin-like growth factor I (IGF-I), growth hormone (GH), insulin, triiodothyronine, and thyroxine, and plasma glucose response to insulin challenge. The effect of plane of nutrition on plasma concentrations of IGF-I and insulin was also determined and a clinical screen of blood chemistries was conducted to determine effects of calf type. Plasma IGF-I was six times higher in control calves compared with miniature calves (209.0 vs 35.0 ng/ml; P = 0.001). However, miniature calves had mean plasma GH about six times higher (37.8 vs 6.2 ng/ml; P = 0.004) and had twice as many secretory episodes (9 vs 4.5; P = 0.005) over an 8-hr sampling period. Plasma concentrations of triiodothyronine (2.54 vs 1.80 ng/ml) and thyroxine (88.8 vs 56.2 ng/ml) were higher in control compared with miniature calves (P = 0.001), but concentrations of triiodothyronine and thyroxine in both calf types were within normal ranges. Although miniature calves displayed similar plasma glucose concentrations to controls, hypoglycemic response to insulin challenge tended to be greater in miniature calves. Nutritional regulation of circulating IGF-I appeared to be intact in miniature as well as control calves, as evidenced by a reduction in plasma IGF-I concentration following a decrease in plane of nutrition, and a subsequent increase in plasma IGF-I concentration following realimentation. Serum urea nitrogen was lower (P = 0.02) in control compared with miniature calves. These data describe a miniature condition in Brahman cattle that is manifested by apparently normal proportioned growth but small stature, and that is associated most notably with abnormally low circulating concentrations of IGF-I in the presence of paradoxically high circulating concentrations of GH. This condition appears to be similar to Laron dwarfism in humans, in which the low IGF-I is caused by an abnormality in the GH receptor.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0037-9727
pubmed:author
pubmed:issnType
Print
pubmed:volume
197
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
450-7
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Endocrine characteristics of a miniature condition in Brahman cattle: circulating concentrations of some growth-related hormones.
pubmed:affiliation
U.S. Department of Agriculture, Agricultural Research Service, Subtropical Agricultural Research Station, Brooksville, Florida 34605-0046.
pubmed:publicationType
Journal Article