Decreased glucose response to insulin is maximal within 24 hours of somatotropin injection in growing pigs.
Porcine somatotropin (pST) administration reduces the sensitivity of pigs to insulin, and after several days of treatment, it alters baseline circulating concentrations of pST, insulin, glucose, and other metabolites. The length of time required to develop this reduction in whole-body insulin sensitivity has not been established. To investigate this, eight castrate pigs received daily injections of either recombinant pST (120 micrograms/kg BW) or exicipient. Intravenous insulin tolerance tests (1.0 microgram/kg BW) were done before the first pST injection (Day 0) and on Day 1, 3, 5, and 8 of pST treatment. Control animals had insulin tolerance tests on Day 0 and again on Day 8 of treatment. By Day 8, the glucose response to the insulin tolerance tests in pST-treated pigs was 45% of the response of the control group (P < 0.01). Glucose response areas between Day 1, 3, 5, and 8 of pST treatment were not different (P > 0.10). The maximum effect of pST on glucose response to insulin was achieved by Day 1. Therefore, factors responsible for the development of reduced whole-body insulin sensitivity in pST-treated pigs are fully expressed within 21 hr of the initial pST treatment.
Department of Animal Science, Cornell University, Ithaca, NY 14853 USA.
J A
JA
Kerber
D
D
Wray-Cahen
R D
RD
Boyd
D E
DE
Bauman
D000818:Animals; D001786:Blood Glucose / Q000032:analysis / Q000378:metabolism*; D015309:Glucose Clamp Technique / Q000662:veterinary; D005951:Glucose Tolerance Test / Q000662:veterinary; D013006:Growth Hormone / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D007279:Injections, Subcutaneous / Q000662:veterinary; D007328:Insulin / Q000097:blood / Q000494:pharmacology*; D008297:Male; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000494:pharmacology; D013552:Swine / Q000097:blood / Q000254:growth & development / Q000378:metabolism*
D001786:Blood Glucose; D007328:Insulin; D011994:Recombinant Proteins; D013006:Growth Hormone