The dissociation curve for goose blood

Respiration Physiology (1967) 3, 302-306; North-Holland Publishing Company, Amsterdam

THE DISSOCIATION

CURVE FOR GOOSE BLOOD’

L. A. DANZER AND J. E. COHN (7) Department

of Medicine,

University of Kentucky

Medical Center, Lexington,

Kentucky,

U.S.A.

Abstract. The oxyhemoglobin dissociation curves for goose blood were determined at pH values of 7.25, 7.4 and 7.6. Curves were constructed by polarographic analyses of 02 tension and spectrophotometric determination of Hb saturation. The curves obtained showed a significant displacement to the right in comparison with human dissociation curves. Also, the hemoglobin saturation never exceeded 95 % up to an oxygen tension of 150 mm Hg (pH 7.40). Bohr effect Oxygen dissociation curve TAO

The fact that the blood of avians differs from that of mammals in many respects would seem to make it an interesting subject for the study of its dissociation curves. The differences include nucleated red cells; different globins, although the heme is probably the same, and the presence of more than one type of hemoglobin in the erythrocyte (BELL and STURKIE, 1965). In spite of these differences, the amount of information available on the oxyhemoglobin dissociation

curves of avians is still small when compared

to that of mammals,

although recently more work has been appearing in this area. The oxyhemoglobin dissociation curve of the domestic hen has been described (CHIODI and TERMAN, 1965). More recently Bartels et al. studied the oxygen affinity of chicken blood before and after hatching. (BARTELS, HILLER and REINHARDT, 1966). In conjunction with other work being done on avian respiration in this laboratory it was decided to determine the oxyhemoglobin dissociation curves of geese. Methods Fresh whole heparinized blood was used throughout the study. The blood was tonometered with gases of various oxygen and carbon dioxide tensions using a continuous flow method. No attempt was made to adjust the pH of the blood by any other method than the effect of changing the partial pressure of CO, in the equilibrating gas. Blood O2 and CO, tensions were measured using appropriate electrodes (InstruAccepted for publication 12 June 1967. l Supported by National Institute of Health Grant HE-08932. 302

303

DISSOCIATION CURVE FOR GOOSE BLOOD

mentation

Laboratory,

Inc. Model

113). A Radiometer

pH meter Model pH 4, with

a microelectrode was used for blood pH measurements. Hemoglobin saturations were determined spectrophotometrically Model DB spectrophotometer. has been described elsewhere

with a solution of Triton X-100 in a sodium formula for calculating saturations is : Percent Saturation R unkn

-

L

borate

buffer (DEIBLER et al. 1959). The

100

x

=

using a Beckman

The sample cuvette used for determining saturations (DANZER and COHN, 1964). Samples were hemolyzed

Rsat-Rred

where R Optical

density

at 475 rnp

= Optical

density

at 506 rnp

Tonometry data obtained Completely of 95 percent samples were dioxide.

and all measurements were carried out at 42 “C except for one set of at 37.5 “C. The normal central temperature of the goose is 42 “C. saturated blood samples were prepared by tonometry with a gas mixture oxygen, 5 percent carbon dioxide. Completely deoxygenated blood prepared by tonometry with 95 percent nitrogen 5 percent carbon

loo-

80-

I

OO

I

I

I

I

I

I

I

20

40

60

80

100

120

140

OXYGEN Fig. 1. The dissociation

TENSION

I

160

mm. Hg

curves for goose blood at 42 “C compared

to human blood at 37.5 “C.

304

L. A.DANZER

AND J.E. COHN

Results Fig. 1 shows the dissociation human

curves obtained

at a temperature

of 42 “C. The normal

curve for pH 7 4 and 37.5 “C. BARTELS et al. (1961) is included

The curves shown in fig. 1 are smoothed

curves and were obtained

samples from twelve geese, all of the same type. Increasing temperature causes dissociation curves to shift that the difference in position between the human curve curve at 42 “C was not due to the temperature difference, curve was determined experimentally at 37.5 “C. Human time as the goose blood as a check on the technique. The

for reference. using

blood

to the right. To demonstrate at 37.5 “C and the goose the position of the goose blood was run at the same results are shown in fig. 2.

LOG. p0, Fig. 2. The effect of temperature on the dissociation curve of the goose. o-o-points for standard human dissociation curve, X points: experimentally determined human blood data.

DISSOCIATION CURVEFORGOOSEBLOOD

305

In fig. 2 the data is presented in terms of the Hill equation: log y/(1 -y)=log where y =fractional

k+n log Po,

saturation, and k and n are constants.

Discussion

The technique used in this laboratory for the spectrophotometric determination of hemoglobin saturations yields results which differ from values obtained by the Van Slyke manometric procedure by an average of 1.1 percent saturation (DANZERand COHN, 1964). The errors in saturations obtained in this work are estimated to average no greater than this value of 1. I percent. Accuracy of pH measurements is estimated to be at least 0.01 pH units. The polarographic method of determining oxygen tension is estimated to be within + 1 mm Hg of the correct oxygen tension. In view of the small potential errors in measurement the observed differences between the dissociation curves as depicted in figs. 1 and 2 are significant. It can be seen from fig. 1 that the dissociation curve for geese is similar in shape to the mammalian curve but is displaced significantly to the right. This displacement appears to be in general agreement with other work on avians. A comparison of the results obtained in this study with those reported by other workers is given in table 1. Since it is known that increasing temperature shifts the dissociation curve to the right, it was decided to determine the position of the goose curve at 37.5 “C!.It can be seen from fig. 2 that even at this temperature the goose curve is still displaced to the right with respect to the human curve. The human blood points which were run at the same time show good agreement with the accepted curve. The agreement provides a verification of the accuracy of the method. These results are in general agreement with the work of WASTLand LEINER(1931). They reported a change in T,, of about 6 or 7 mm Hg in decreasing the temperature from 42 “C to 37.5 “C. In this study a shift in T,, of about 9 mm Hg was observed TABLE Investigators

Species

1

T5o

Temp.

pH

Pco,

-

Studied CHRISTENSENand DILL (1935)

Goose

45

37.5

7.10

MORGANand CHICHESTER

Hen

32

40

-

10

(1935)

Hen

55

40

-

40

Hen

80

Hen

51

40 40

7.10

100 -

CHIODIand TERMAN(1965)

Hen

54

42

7.50

-

BARTELS, HILLER and

Cock

48.9

39

7.40

-

REINHARDT(1966) DANZER and COHN

Goose

53.5

42

7.25h.01

69f7

(this work)

Goose

46.0

42

7.40+

46&5

Goose

37.0

42

7.591.02

.02

21&3

L.

306

A. DANZER AND J. E. COHN

for the same temperature interval. The difference between the reported values may be partly due to the irregular shaped curves obtained by Wastl and Leiner. In any event, the rightward shift of the goose dissociation curve cannot be explained by the temperature difference alone. A possible explanation of the remainder of the shift would be that the avian hemoglobin has a lower affinity for oxygen than normal human hemoglobin (WASTL and LEINER, 1931). Another interesting feature of the goose curves shown in fig. 1 is that the blood remains slightly desaturated over at an oxygen tension of 140 mm Hg [95 percent saturated (pH 7.4)]. This general effect has been reported for chicken blood (CHIODI and TERMAN, 1965), and is in agreement with the work of CHRISTENSEN and DILL (1935) using the blood of other avian species. The Bohr effect is larger for goose blood than for human blood. The change in T,, per 0.1 pH unit is about 5.0 mm Hg for goose blood compared with a value of approximately 2.9 mm Hg for human blood. CHRISTENSENand DILL (1935) studied the Bohr effect in hemoglobin solutions of avian blood and obtained results similar to those reported here for whole blood. References BARTELS,H., K. BETKE,P. HILPERT, G. NIEMEYERand K. RIEGEL(1961). Die sogenannte StandardOz-Dissoziationskurve

des gesunden erwachsenen Menschen. Arch. Ges. Physiol. 272: 372-383.

BARTELS,H., G. HILLERand W. REINHARDT(1966). Oxygen affinity of chicken blood before and after hatching. Respir. Physiol.

I : 345-356.

BELL, D. J. and P. D. STURKIE(1965). Chemical constituents of blood. In: Aviun Physiology, by Paul D. Sturkie, Chapter 2. CHIODI, H. and J. W. TERMAN(1965). Arterial blood gases of the domestic hen. Am. J. Physiol. 208: 798-800. CHRISTENSEN, H. and D. B. DILL (1935). Oxygen dissociation

curves of bird blood. J. Biol. Chem.

109 : 44348. DANZER, L. A. and J. E. COHN (1964). A new cuvette for the spectrophotometric hemoglobin

saturations. J. Lab. and Clin. Med. 63

measurement of

: 355-358.

DEIBLER,G. E., M. S. HOLMES,P. L. CAMPBELLand J. GANS (1959). Use of triton X-100 as a hemolytic agent in the spectrophotometric

measurement of blood

02 saturation. J. Appl. Physiol.

14: 133-136. HILL, A. V. (1913). Thecombination

of hemoglobin with oxygen and with carbon monoxide. Biochem.

J. 7: 471488. MORGAN, V. E. and D. F. CHICHESTER (1935). Properties of the blood of the domestic fowl. J. Biol. Chem.

I IO: 285-298.

WASTL, H. and G. LEINER(1931). Beobachtungen Physiol. 227: 367474.

iiber die Blutgase bei VGgeln. Ppigers

Arch. ges.