Plasma ACTH Levels in the Human Fetus and Neonate as Related to Age and Parturition¹

Abstract

ACTH levels were measured by radioimmunoassay in umbilical cord plasma from fetuses, in capillary plasma from neonates, and in venous plasma from adults. Cord plasma was obtained from term fetuses delivered under the following four conditions: 1) vaginally after spontaneous labor, 2) by cesarean section after spontaneous labor, 3) by cesarean section before spontaneous labor, and 4) vaginally after oxytocin-induced labor.The ACTH values in these four groups of term fetuses did not differ significantly. Thus, human umbilical cord ACTH does not rise with spontaneous labor. The concentration of ACTH in cord plasma prior to the 34th gestational week was 241 ± 33 pg/ml (mean and SE); and in term fetuses, the ACTH levels were 143 ± 7 pg/ml. In infants during the first week of life, the ACTH concentration was 120 ± 8 pg/ml. The mean ACTH level in all fetuses was higher than the afternoon values in normal adults (43 ± 4 pg/ml). These results suggest that an increased ACTH concentration in fetal plasma is not essential for the initiation of labor in the human. (/ Clin Endocrinol Metab 39: 269,1974)

The ontogenesis of human fetal hormones. III. Prolactin.

“…However, estradiol and estrone in the fetal circulation originate mainly from precursors secreted by the maternal adrenal cortex (60,61), therefore, the circulating levels of these two steroids in the fetus should not be greatly affected by anencephaly. This was recently demonstrated in one anencephalic infant in whom the high plasma concentrations of unconjugated 17 f-estradiol and estrone in umbilical cord blood were in the normal range (62 (21)(22)(23)(24). In the case of hGH., although a GH release inhibiting factor or somatostatin has been described (63), the very low GH plasma levels usually found in anencephalic infants suggest that GH secretion in the fetus is primarily under the influence of a growth hormone releasing factor (GRF).…”

Corticotropin-Releasing Hormone Directly and Preferentially Stimulates Dehydroepiandrosterone Sulfate Secretion by Human Fetal Adrenal Cortical Cells*

“…ACTH secreted by the fetal pituitary, and acting in part via locally produced growth factors, including insulin-like growth factor-II (9) and basic fibroblast growth factor (10), is the principal trophic regulator of fetal zone growth and function. However, the postnatal involution of the fetal zone, despite unchanged exposure to ACTH (11), suggests that the fetal zone also is regulated by a pregnancy specific factor(s). This factor may be CRH.…”

Heterogeneity of adrenocorticotrophin in the pituitary gland and plasma during the perinatal period

“…The evolution of various molecular forms of ACTH are reported to be different in adult pars neurointermedia, i.e. the proteolytic cleavage of ACTH, -39 produces several peptides of lower molecular weight, such as a-MSH (ACTH!_!3 and CLIP (ACTH 18 -39 ) (Gianoulakis et al, 1979 ;Eipper, 1979, 1980 ;Eipper and Mains, 1980) ; the adult pars neurointermedia contains little ACTH l-39 (Crine et a/., 1979 ; Gianoulakis et al, 1979) but a lot of a-MSH, CLIP and ¡3-endorphin (Scott et al, 1974a, b ;Kraicer, 1977 ;Lissitsky et al, 1978 ;Gianoulakis et al, 1979 ;Jackson and Lowry, 1979 ;Chretien and Seidah, 1981 (Allen et al, 1973(Allen et al, , 1974Miyakawa et a/., 1974 ;Winters et al, 1974). Similarly, plasma ACTH levels are reduced in encephalectomized rats (Dupouy and Chatelain, 1981 ;Chatelain and Dupouy, 1981a).…”