Renal function studies in normal and toxemic pregnant sheep

Area of Science:

• Physiology
• Renal Function
• Pregnancy Studies

Background:

• Pregnancy significantly alters maternal physiology, including renal function.
• Ovine pregnancy toxemia is a condition that can arise from nutritional stress, impacting maternal and fetal health.

Purpose of the Study:

• To investigate the impact of normal twin pregnancy and experimentally induced pregnancy toxemia on renal hemodynamics and function in sheep.
• To compare renal function in pregnant and non-pregnant ewes, and to assess the effects of starvation-induced toxemia.

Main Methods:

• Surgical preparation of sheep with vascular cannulas for precise measurements.
• Measurement of renal blood flow, plasma flow, glomerular filtration rate (GFR), and maximal tubular transport of para-aminohippuric acid (TmPAH).
• Comparison of parameters in nonpregnant, normally pregnant, and toxemic pregnant ewes subjected to starvation.

Main Results:

• Renal blood and plasma flow increased during normal pregnancy but showed no change per body weight.
• Glomerular filtration rate (GFR) and TmPAH were significantly elevated in pregnant ewes compared to non-pregnant ewes, indicating functional renal hypertrophy.
• Starvation-induced toxemia led to a 25-30% decrease in renal blood and plasma flow and a significant reduction in GFR, while TmPAH remained unaffected.

Conclusions:

• Pregnancy in sheep is associated with functional renal hypertrophy.
• Ovine pregnancy toxemia, caused by starvation, significantly impairs renal hemodynamics and filtration, likely due to metabolic disturbances.
• The renal dysfunction in ovine pregnancy toxemia differs from human preeclampsia.