Transcapillary exchange and retention of fluoride, strontium, EDTA, sucrose, and antipyrine in bone

Abstract

The extractions of 85Sr2+, 18F-, sucrose-14C, EDTA-51Cr, and antipyrine-14C in bone were determined by the multiple indicator-dilution method. Fluoride and strontium extractions were 18 to 70% during a single transcapillary passage, and those of EDTA and sucrose were from 11 to 59%, whereas extraction of antipyrine was 87%. Injections of 85Sr2+ and 18F- made when perfusion was done alternately with blood and plasma resulted in similar fractional extractions. When flow and extraction were measured simultaneously, extraction was related inversely to flow.

Fig. 1

Outflow dilution curves of ¹⁸F⁻, albumin-⁵¹Cr, and sucrose-¹⁴C injected in saline into nutrient artery of adult dog tibia (upper panel) and extraction curves for sucrose and fluoride (lower panel)

Fig. 2

Outflow dilution in dog H-236, run 4, h(t) (upper panel), and extraction curves, E(t) (lower panel), for albumin, fluoride, and strontium in pump-perfused dog tibial diaphysis. Impulse injection was made into nutrient artery. Curves of E(t) slope upward from t = 15 to t = 40s and then diminish. Extraction continues longer for F⁻ than for Sr²⁺; E_Sr(t) crosses zero, or h_Sr(t) becomes greater than h_alb(t), at 1½ min, whereas E_F(t) remains positive for 3 min. E_max is taken near peak of reference curve; E_F = 0.41, E_Sr = 0.36

Fig. 3

Outflow dilution curves of ¹⁸F⁻, albumin-⁵¹Cr, and antipyrine-¹⁴C (upper panel). Instantaneous extraction of antipyrine-¹⁴C is considerably higher than that of ¹⁸F but is still less than unity (lower panel). There is evidence of recirculation at end of curve

Fig. 4

Data from experiments in sets 4 and 5, Table 3, E_F or E_Sr. Instantaneous extraction near peak of reference curve is plotted against flow (upper panel) and against net extraction (lower panel). Extraction decreases with flow

Fig. 5

Data from experimental set 6. Instantaneous and net extraction are plotted against flow