Plasma half time of unmodified hemoglobin (UHb) and two intramolecularly cross-linked hemoglobins (alpha alpha XL and beta beta XL) was measured in anesthetized rats after an intravenous bolus of 20 mg.100 gm.-1 To rule out the possibility that differences among plasma half times might be caused by differences in acute effects on renal excretory function, glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) were measured simultaneously with plasma half time. Experiments were also done to determine whether higher doses (60 to 100 mg-1.100 gm-1) of these compounds had a delayed effect (48 hours) on GFR or ERPF. Massive urinary excretion of UHb occurred; however, only 1% of the alpha alpha XL and none of the beta beta XL was excreted. Plasma half time of alpha alpha XL and beta beta XL averaged 3.3 hours, or four times longer than UHb. In no case did a decrease in GFR or ERPF occur. Instead, a transient increase in GFR, ERPF, urine flow, and systemic blood pressure was seen. Similar increases occurred after albumin administration, suggesting expansion of vascular volume as the initiating factor. Renal functions at 48 hours after 60 to 100 mg.100 gm-1 of UHb, alpha alpha XL or beta beta XL were not different from control (albumin). Intratubular hemoglobin casts or intravascular precipitates were not evident in acute or 48-hour studies. At 48 hours Perls' staining material was found in one alpha alpha XL specimen at 3 hours after administration. Perls' staining material was present in renal tubule cells in all but the albumin-treated kidneys.(ABSTRACT TRUNCATED AT 250 WORDS)
