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Plasma from six chronically catheterised sheep fetuses of 113–126 days conceptual age showed high levels of corticotrophin at all ages with somewhat higher values towards term. Plasma cortisol was not clearly related to corticotrophin in individual samples but was highly correlated in the pooled data. Short bouts of hypoxia (5–10 min 10% O₂ in N₂ to the mother) produced no significant change in either corticotrophin or cortisol although small transient changes in PO₂ and lactate occurred. The high levels of corticotrophin suggest that the possibility of stress in the chronically catheterised preparation must be considered.

An investigation was carried out to examine why a glucose oxidase-peroxidase-orthodianisidine method for plasma glucose, without protein precipitation, gave low results for neonatal blood. The magnitude of the difference between the results with and without protein precipitation was examined in a clinical neonatal series, and in sera to which bilirubin, hemolysate, pure hemoglobin, and uric acid had been added. Systematic linear inhibition was demonstrated with bilirubin, and the results suggested that high concentrations of hemolysate and uric acid could also interfere. Use of alkaline protein precipitants eliminated the inhibition. Dextrostix test results for neonatal blood are compared with results of conventional glucose analyses and possible sources of discrepancy examined.

Continuous tissue pH and intermittent central arterial pH were measured in six rabbits during 10-min exposures to a mixture of 10% CO2 and 90% O2. In control and recovery situations tissue pH was more acidic than arterial pH by a mean value of 0.07 pH units. During periods of rapidly increasing pCO2, the steady state relationship was inverted with tissue pH being more alkaline than arterial pH. After a second exposure to CO2, mean tissue pH values did not recover to baseline. It is concluded that in the rabbit during acute hypercarbia, the relationship of tissue to central pH is variable. The possible implications of these results in human fetuses during labor are discussed.