Coxam V, Davicco M J, Opmeer F A, Ravault J P, Barlet J P
Reprod Nutr Dev (1980). 1987;27(2B):533-45. doi: 10.1051/rnd:19870412.
Plasma somatotropin (GH) and somatomedin C (IGF1) concentrations were measured by radioimmunoassay in 3-dy old and 10-day old calves intravenously injected with growth hormone releasing factor (GRF) 1-44, GRF 1-29 or thyrotropin-releasing hormone (TRH). In 3 day old animals the increase in plasma GH concentration was GRF 1-44 dose-related (50, 100, 200 pmoles . kg(-1) of body wt). In four 10-day old calves injected with the lowest dose, the increase in plasma GH concentration was not different from that observed in four 3-day old animals treated with 200 pmoles . kg-1 of body weight. However, the response observed in four 3-day old calves injected with GRF 1-29 (50 pmoles . kg-1 of body wt) was not different from that observed following the same treatment in four 10-day old calves. In four 3-day old calves TRH (10 nmoles . kg-1 of body wt) induced a significant rise in plasma GH, prolactin (Prl), thyroxine (T4) and triiodothyronine (T3) concentrations. The same dose of TRH injected into four 10-day old calves elicited a similar rise in plasma T3 and T4 concentrations, but plasma GH and Prl increased less than in 3-day old animals. In three 3-day old or 10-day old calves born spontaneously before term (258-260 days of gestation), the increase in plasma Prl and GH concentrations following TRH was not different from that observed in mature calves of the same postnatal age. Neither GRF 1-44, GR 1-29 nor TRH elicited any significant change in plasma IGF1, insulin or glucose concentration in any group of calves.
通过放射免疫分析法测定了静脉注射生长激素释放因子（GRF）1-44、GRF 1-29或促甲状腺激素释放激素（TRH）的3日龄和10日龄犊牛的血浆生长激素（GH）和胰岛素样生长因子C（IGF1）浓度。在3日龄动物中，血浆GH浓度的增加与GRF 1-44剂量相关（50、100、200皮摩尔·千克⁻¹体重）。在四只注射最低剂量的10日龄犊牛中，血浆GH浓度的增加与四只接受200皮摩尔·千克⁻¹体重治疗的3日龄动物中观察到的增加没有差异。然而，在四只注射GRF 1-29（50皮摩尔·千克⁻¹体重）的3日龄犊牛中观察到的反应与在四只10日龄犊牛中进行相同治疗后观察到的反应没有差异。在四只3日龄犊牛中，TRH（10纳摩尔·千克⁻¹体重）引起血浆GH、催乳素（Prl）、甲状腺素（T4）和三碘甲状腺原氨酸（T3）浓度显著升高。向四只10日龄犊牛注射相同剂量的TRH，血浆T3和T4浓度出现类似升高，但血浆GH和Prl的增加低于3日龄动物。在三只妊娠258-260天自然早产的3日龄或10日龄犊牛中，TRH后血浆Prl和GH浓度的增加与相同出生后年龄的成熟犊牛中观察到的增加没有差异。在任何一组犊牛中，GRF 1-44、GR 1-29或TRH均未引起血浆IGF1、胰岛素或葡萄糖浓度的任何显著变化。
