Plasma and Adrenal Cortisol Concentrations in Foetal, Newborn and Mother Guinea-Pigs During the Perinatal Period

Abstract

Concentrations of cortisol, corticosterone and cortisone in the plasma and adrenal glands, liver glycogen and plasma glucose of foetal, newborn and mother guinea-pigs were estimated during the last 6 days of pregnancy and throughout the first 24 h post partum. At the same time progesterone was measured in the plasma of the mother. During the prepartum rise in foetal plasma cortisol levels and liver glycogen, no significant change in the foetal adrenal cortisol content was observed. The plasma and adrenal cortisol concentrations of the mother were much higher than those observed in the foetus and increased significantly before parturition. In the mother as in the foetus, cortisone and corticosterone represent only a small percentage of corticosteroids compared with cortisol. These results indicate that the autonomous capacity of foetal adrenals, inhibited by maternal secretions before term, appears suddenly at birth.

Comparative enzymology of 11β-hydroxysteroid dehydrogenase type 1 from six species

“…Cortisol concentrations reach approximately 30% of the levels of corticosterone in hamsters (Ottenweller et al 1985). In guinea pig, cortisol is the predominant glucocorticoid (Dalle & Delost 1976); however, this animal is relatively resistant to glucocorticoids and shows a reduced affinity of cortisol to GR compared with humans (Keightley et al 1998). Although some species use cortisone (human, dog, guinea pig) and others 11-dehydrocorticosterone (hamster, rat, mouse), we did not find a correlation between substrate use and affinity.…”

The regulation of glucocorticosteroid secretion during the perinatal period

“…Furthermore, the role of placental enzymes in steroid metabolism has been well documented in several species, especially in humans (Diczfalusy, 1962(Diczfalusy, , 1969Murphy, 1981) (Osinski, 1960 ;Villee et al, 1961 ; Goldkrand et al, 19761. We demonstrated a similar process in guinea-pigs (Dalle and Delost, 1976) showing that the cortisone/cortisol ratio in newborn plasma might be used as an index of adrenal maturity.The origin of fetal corticosteroids was investigated and their metabolism measured by infusing radioactive cortisol to pregnant guinea-pigs or to their fetuses.At the end of gestation, 90 % of the fetal cortisol was of maternal origin ; the secretion rate of fetal adrenal was very low as was metabolism. The value of the metabolic clearance rate (MCR) of cortisol in the mothers was found to be lower than in non-pregnant females due to the high levels of CBG which protected the cortisol against metabolism.…”

Maturation of glucocorticosteroid activity in the foetal guinea-pig during the end of gestation

“…High plasma cortisol levels have been observed in newborn guinea-pigs (Dalle and Delost,1974). These high levels result from a regular rise in foetal plasma cortisol levels during the last days of gestation, which parallels the increase in maternal plasma and adrenal cortisol concentrations, foetal adrenal cortisol content increasing only during the last 24 hrs of gestation (Dalle and Delost, 1976). Recent studies (Dalle and Delost, 1979) Murphy (1967), modified as described previously (Dalle and Delost, 1976).…”