Hydroxyproline in the allantoic fluid of the mare.

Abstract

The occurrence of free amino acids in the amniotic and allantoic fluid of the cow and sow has recently been reported (Martin\l=c%v\i\l=c'\,Herak & Krvavica, 1969). In this study, the results obtained with the mare's allantoic fluid are recorded and show that substantial quantities of glutamic acid, glycine, alanine and proline and, in addition, a surprisingly large amount of hydroxyproline are present. This imino acid was also detected in the allantoic fluid of pregnant cows and sows, but in very much lower concentrations. Animal organs and body fluids contain, on the whole, very little hydroxyproline. In the blood, Wiss (1949) found an average of 0\m=.\132mg/100 ml in rats, 0\m=.\171in rabbits, and 0\m=.\290in guinea-pigs; the quantities excreted daily in the urine were of the order of 10 \g=m\g.According to James (1955), there are about 100 \g=m\ghydroxyproline in 100 ml blood plasma; he also found 2\m=.\5\g=m\gin 0\m=.\5ml of packed white blood cells, but none in plasmolysed erythrocytes. Bates, McGowen & Talmage (1962) found 0\m=.\080\g=m\mol/mlof free hydroxyproline in plasma of normal rats and Prockop, Keiser & Sjoerdsma (1962), studying two human subjects, found 1\m=.\2\g=m\gand 1\m=.\6\g=m\g/mlof free hydroxyproline in plasma. Under controlled fasting conditions, the two subjects excreted about 1 \g=m\gof free hydroxyproline/min. Lindstedt & Prockop (1961) investigated the excretion of hydroxyproline in rats of varying ages and found that 3-week-old rats excreted 73 \g=m\g/24hr of free hydroxyproline, while 2-year-old rats excreted two to three times less. Jasin & Ziff (1962) have also determined the free hydroxyproline in the urine of the rats and have found that 22\m=.\2\g=m\gof this imino acid is excreted/24 hr. In the rat spleen, there is also a small amount hydroxyproline (Akerfeldt, 1955) and, in the rat liver, Wolf & Berger (1958) found only 1\m=.\1\g=m\gin the whole organ; however, after oral administration of proline, there