Fairclough R J, Hunter J T, Peterson A J, Welch R A
Acta Endocrinol (Copenh). 1981 Mar;96(3):406-12. doi: 10.1530/acta.0.0960406.
Infusing dexamethasone at rates of 0.1, 1.0 or 10 mg/day into 6 foetal calves at day 240 of gestation (2 calves per infusion rate), induced premature calving in a mean 12, 9 and 3 days respectively. Maternal plasma concentrations of progesterone, oestrone, oestradiol-17 beta and prostaglandin F or 13,14-dihydro-15-keto-prostaglandin F, and foetal plasma concentrations of oestrone, oestradiol-17 beta and corticosteroids were monitored until calving. The maternal hormone changes observed for all cows were a decline in progesterone, and a rise in both oestrogen and prostaglandin F concentrations before calving. Dexamethasone infused at a rate of 1.0 and 10.0 mg/day suppressed plasma corticosteroids in the foetus; however at 0.1 mg/day, foetal corticosteroids increased tenfold during the last 3 days before calving. At the lowest rate of infusion, dexamethasone had no effect on foetal oestrogen levels, but at rates of 1.0 and 10.0 mg/day there was a marked rise in foetal plasma levels of oestrogen.
在妊娠第240天，以每天0.1、1.0或10毫克的速率给6头胎牛输注地塞米松（每个输注速率2头牛），分别平均在12、9和3天内诱发早产。监测母体血浆中孕酮、雌酮、雌二醇 - 17β和前列腺素F或13,14 - 二氢 - 15 - 酮 - 前列腺素F的浓度，以及胎儿血浆中雌酮、雌二醇 - 17β和皮质类固醇的浓度，直至分娩。观察到所有母牛的母体激素变化是孕酮下降，分娩前雌激素和前列腺素F浓度均升高。以每天1.0和10.0毫克的速率输注地塞米松可抑制胎儿血浆中的皮质类固醇；然而，以每天0.1毫克的速率输注时，胎儿皮质类固醇在分娩前最后3天增加了10倍。在最低输注速率下，地塞米松对胎儿雌激素水平没有影响，但以每天1.0和10.0毫克的速率输注时，胎儿血浆中的雌激素水平显著升高。
