Effect of thyroid hormone on concentrations of plasma calcitonin in broiler chicks.
The purpose of these studies was to determine the effect of thyroidectomy (Tx), and thyroid hormone (T3/T4) treatment on concentrations of plasma CT in chicks. In addition, the turnover of CT in Tx- and T3/T4-treated chicks was estimated using a novel nonradioactive salmon CT preparation. One-week-old broiler chicks (Gallus domesticus) (n = 75) were divided into three groups. Group I was sham-injected daily (i.m. saline), Group II was injected with 50 micrograms/day of T3/T4 while Group III was injected with the goitrogen, methimazole, (150 mg/kg BW per day) for 8 weeks. Chicks (8-9 weeks old) were implanted with catheters in the brachial wing vein and administered ruthenium-labeled salmon CT. Blood samples were collected at 30 s, 1, 2, 4, 8, 20 min, and 3 h after injection. Results showed that concentrations of plasma CT were decreased in T3/T4-injected birds. There was no significant effect of methimazole on circulating concentrations of plasma CT. The half-life of CT was significantly increased (P < 0.05) in both T3/T4-injected (n = 6; 1.34 +/- 0.16 min) and goitrogen-treated birds (n = 2; 5.81 +/- 2.83 min) compared to controls (n = 7; 54 +/- 3 s) The results demonstrate that changes in concentrations of plasma thyroid hormones can significantly affect concentrations of plasma CT.
Klandorf
H
H
Division of Animal and Veterinary Sciences, College of Agriculture and Forestry, West Virginia University, Morgantown 26506-6108, USA. HKLAND@WVU.EDU
Boyce
C S
CS
Holt
S B
SB
Iqbal
M
M
Killefer
J
J
Peterson
R A
RA
Deaver
D R
DR
D000375:Aging; D000818:Animals; D013956:Antithyroid Agents / Q000494:pharmacology; D001835:Body Weight; D002116:Calcitonin / Q000097:blood*; D002118:Calcium / Q000097:blood; D002645:Chickens / Q000097:blood*; D005260:Female; D008713:Methimazole / Q000494:pharmacology; D009929:Organ Size; D013961:Thyroid Gland / Q000033:anatomy & histology; D013965:Thyroidectomy; D013974:Thyroxine / Q000494:pharmacology*; D014284:Triiodothyronine / Q000494:pharmacology*
D013956:Antithyroid Agents; D014284:Triiodothyronine; D008713:Methimazole; D002116:Calcitonin; D013974:Thyroxine; D002118:Calcium