URINARY CATECHOLAMINE EXCRETION AND PLASMA NEFA CONCENTRATION IN SMALL-FOR-DATE INFANTS

Abstract

Urinary catecholamine excretion, blood glucose, and plasma nonesterified fatty acids (NEFA) concentration were studied in five full-term, seven premature, and 22 small-for-date (SFD) babies (16 at term and six prematurely born) during the first 8 to 10 days of life. Episodes of hypoglycemia (arbitrarily designed as < 40 mg/100 ml for full term and < 30 mg/100 ml for premature infants) were observed between the second and fifth day of age in 12 SFD babies. During their low blood sugar period, these infants exhibited a significantly higher catecholamine excretion (three- to fourfold for norepinephrine and five- and sixfold for epinephrine) when compared to full term, premature, and "nonhypoglycemic" SFD babies. All SFD babies during the first 2 days of life showed a significantly higher plasma NEFA concentration than the other groups of neonates; among the former, the hypoglycemic ones had a tendency to maintain for a longer period a higher NEFA concentration than the nonhypoglycemic ones. These findings show that SFD babies are capable of reacting to an hypoglycemic stress by mobilizing their fat stores and by releasing catecholamine; therefore, adrenal medullary unresponsiveness cannot be considered as a cause of their transient neonatal hypoglycemia.