DEVELOPMENT OF THE FETAL RAT ADRENAL IN PROLONGED PREGNANCY.

Abstract

The adrenals of rat fetuses obtained from mothers whose pregnancy was prolonged by injection of progesterone were compared with those of fetuses in normal pregnancy and of neonatals, with particular reference to the weight, ascorbic acid content and histology.During normal pregnancy, the fetal adrenal weight steadily increased up to the 21st day of pregnancy, showing an especially pronounced rise from the 20th to 21st day of pregnancy. From the 21st to 22nd day, there was no reliable in crease in fetal adrenal weight. After birth, the adrenal of neonatals was lighter and cortical cells were smaller than those in the fetal stage. Ascorbic acid content increased on the 22nd day of pregnancy, showing little fluctuation after birth. Osmiophilic materials increased in amount. When pregnancy was prolonged for 2 or 3 days, the fetal adrenals did not show atrophy, but gained weight, with a fall in ascorbic acid content. Osmiophilic materials were fewer than in the normal neonatals.The adrenals of progesterone-treated mothers did not show any significant change, neither in weight nor in ascorbic acid content, as compared to those of the normal untreated mothers. Progesterone, when injected to the newborn rats, failed to induce a distinct alteration in adrenal weight and histology, but caused a slight decrease in ascorbic acid content.It is concluded that the retardation of fetal adrenal growth does not occur in prolonged pregnancy.