Morphologic changes in the adrenal glands of fetal and newborn rats following administration of glucocorticoids to the mother during pregnancy

The effects of different steroids on costal and epiphyseal cartilage of fetal and adult rats

The effects of different doses of various steroids on growth, and on costal and epiphyseal chondrocytes, have been studied in prenatal, immature, and adult Long-Evans rats using histochemical techniques, and both light and electron microscopy. Both prenatal and postnatal treatments have been employed. The steroids used were cortisone (CA), betamethasome (BM), and, in the prenatal group only, dexamethasone (DM). Body weight is reduced in all treated rats (except the low dose of CA) by day 17 of gestation, with greater weight reductions occurring in rats receiving the higher dose level of each steroid. In rats treated prenatally or neonatally, and sacrificed postnatally on days 39-43 or days 116-127, body weights, and tibial and tail lengths, are less than in correspondingly aged controls, thus showing a persistence of the effects of treatment. Costal and epiphyseal cartilages in prenatal rats show cellular, synthetic, and ultrastructural alterations induced by treatment with glucocorticoids but the responses are not necessarily comparable. Except for the low dose of DM, the higher doses of each steroid are more effective in inhibiting, or altering, growth and cellular differentiation in the developing fetuses. Surprisingly, a low dose of DM has a more devastating effect on the cells and extracellular matrix of both costal and epiphyseal cartilage, than do higher dose-levels of the various steroids. Low doses of CA and BM are also effective in inhibiting or altering growth and cellular differentiation, but their effectiveness is largely limited to 17 days of gestation. The order of effect of the various doses of the different steroids on fetal cartilage, listed in decreasing order of severity, is as follows: 0.12 DM, 0.24 DM, 0.42 BM, 50 CA, with 25 CA and 0.18 BM being approximately equal and only slightly different from control cartilages. The effect of prenatal or neonatal glucocorticoid treatment on chondrocytes is minimal in the 30-43 days, or 116-127 day, postnatal groups. In immature and adult rats, cortisone affects the chondrocytes more deleteriously than does betamethasone, and a 5.0 mg dose of CA seems to affect chondrocytes, body weight, and tibial and tail lengths more than 0.2 or 7.5 mg doses.

Long-lasting impairment of immune and endocrine systems of offspring induced by injection of dexamethasone into pregnant mice

Dexamethasone was injected daily (2.5 and 5 micrograms/day) into pregnant mice from the 8th gestational day until delivery, and their offspring were examined in terms of body weight, organ histopathology, immunological function, and serum hormone level. Two different postnatal patterns were observed among the treated offspring: one pattern showing a wasting appearance and death within 1 week, and the other showing retardation of growth without any wasting appearance. In the latter, the offspring showed an immunologically impaired antibody-forming capacity to T-cell-dependent antigen (SRBC) and cell-mediated cytolytic T-cell activity. Histologically, the lymphoid tissues, thyroid, and adrenals of these offspring are atrophied and their serum thyroxine (T4) levels were significantly reduced. These results suggest that intrauterine exposure of the fetus to dexamethasone can disrupt the normal development and function of endocrine and immune organs which can lead to early death or retardation of growth after birth.