Wintour E M, Marelyn E, Barnes A, Cahill F, Hardy K J, Horacek I, Scoggins B A
Pediatr Res. 1979 Apr;13(4 Pt 1):265-7. doi: 10.1203/00006450-197904000-00011.
As maternal hyperkalemia quickly induces fetal hyperkalemia, it was decided to investigate the effect of small elevations of plasma [K+] on the peripheral blood aldosterone concentration in chronically catheterized ovine fetuses and to compare this response to that obtained in the adult ewe both pregnant and nonpregnant. Fol elevations of plasma [K+] of 0.1 to 0.3 mmole/liter blood aldosterone concentrations were elevated by 6.7 +/- 4.9 (9) ng/dl in nonpregnant sheep, 6.3 +/- 5.0 (6) in pregnant ewes, but only 0.3 +/- 1.7 (4) in fetal sheep. For increments in plasma [K+] of 0.4--1.0 mmole/liter aldosterone increments in nonpregnant ewes were 9.5 +/- 4.5 (4) ng/dl compared with 10.1 +/- 4.7 (5) in pregnant ewes and 1.5 +/- 2.6 (7) in fetuses. There was no obvious correlation between the age of the fetus and the response to increased plasma [K+]. In effect, the blood aldosterone concentration of the fetus was not elevated by increasing plasma plasma [K+].
The ovine fetus is not able to cope with hyperkalemia by increasing blood aldosterone concentration. Until the fetus is close to term, hyperkalemia may jeopardize the pregnancy by causing placental hemorrhages.
由于母体高钾血症会迅速诱发胎儿高钾血症，因此决定研究血浆[K⁺]轻度升高对长期插管的绵羊胎儿外周血醛固酮浓度的影响，并将此反应与成年母羊（包括怀孕和未怀孕的）的反应进行比较。血浆[K⁺]升高0.1至0.3毫摩尔/升时，未怀孕绵羊的血醛固酮浓度升高6.7±4.9（9）纳克/分升，怀孕母羊升高6.3±5.0（6）纳克/分升，而胎儿绵羊仅升高0.3±1.7（4）纳克/分升。血浆[K⁺]升高0.4 - 1.0毫摩尔/升时，未怀孕母羊的醛固酮升高幅度为9.5±4.5（4）纳克/分升，怀孕母羊为10.1±4.7（5）纳克/分升，胎儿为1.5±2.6（7）纳克/分升。胎儿年龄与对血浆[K⁺]升高的反应之间无明显相关性。实际上，增加血浆[K⁺]并不会使胎儿的血醛固酮浓度升高。
绵羊胎儿无法通过增加血醛固酮浓度来应对高钾血症。在胎儿接近足月之前，高钾血症可能会因导致胎盘出血而危及妊娠。
