Possible Interaction: Hydrocortisone and Tretinoin

“Cortisol alone and the combination of cortisol and RA caused a significant increase in the rate of SP-B gene transcription and also caused a significant increase in SP-B mRNA stability.”

“Cortisol alone and the combination of cortisol and RA significantly inhibited the rate of SP-A gene transcription but had no effect on SP-A mRNA half-life.”

“ RA alone (10(-6) M) had no effect on SP-A mRNA levels and modestly reduced the inhibitory effect of cortisol.”

“RA alone and the combination of cortisol and RA both significantly increased SP-B mRNA levels.”

“Expression of folate-receptor protein in UMSCC 38 cells was also found to be reduced approximately 10-fold when cells were exposed to 1 microM retinoic acid for 48 hours and increased approximately eightfold after a 5-day exposure to 3 microM hydrocortisone.”

“From this point of view we consider that hydrocortisone promotes repair of sublethal damage while retinoic acid inhibits repair.”

“Pretreatment of cells for 48, 72, or 96 h with 100 nM retinoic acid decreased the binding of hydrocortisone to its receptor by only 20%, and only resulted in a small decrease in the total amount of hydrocortisone associated with cells 48 h after the addition of retinoic acid.”

“Simultaneous treatment of SqCC/Y1 cells with hydrocortisone and retinoic acid resulted in mutual antagonism of cornified envelope formation.”

“The changes in keratin expression were evident primarily in the striking stimulation by hydrocortisone or calcium and the virtual suppression by retinoic acid of species in the 56–58 kd region, which have not previously been reported subject to such physiological modulation.”

“Only steroids with GC activity, such as dexamethasone, hydrocortisone , and RU-28362, were capable of increasing the degree of SqCC/Y1 differentiation and antagonizing the inhibitory effects of retinoic acid on the maturation process.”

“Simultaneous treatment with hydrocortisone and retinoic acid indicated mutual antagonism of the effects of these agents on the formation of cornified envelopes.”

“However, two other cell lines (C4-1 and A431) were less competent to spontaneously form cornified cell envelopes and resistant to the induction of envelope competence by hydrocortisone in the presence of retinoic acid.”

“The differentiation capacity of the cells, i.e., ionophore-induced cornified envelope formation, was inhibited by various retinoids and stimulated by hydrocortisone.”

“ Hydrocortisone (10(-6) M) reversed the effect of RA on cell shedding, and increased the proportion of pericellular HA relative to that found in cultures exposed to RA alone.”

“Treatment with either hydrocortisone or oestrogen significantly enhanced proliferation of these cells, whereas retinoic acid inhibited their growth.”