Possible Interaction: Progesterone and Vinblastine

“Moreover, intravenously administered methylprednisolone and intramuscularly administered progesterone significantly enhanced the absorption of VLB , suggesting that parenterally administered P-gp modulators could influence the intestinal absorption of P-gp substrates.”

“The P-gp inhibitors verapamil and progesterone significantly increased the epithelial cell accumulation of both vinblastine and sparfloxacin.”

“In the presence of a Pgp inhibitor such as verapamil, cyclosporine A, or progesterone , the ATP-dependent uptakes of [3H]digoxin and [3H]vinblastine into BBMVs were significantly reduced.”

“ VLB doses of 1.0 micrograms/mL for 4 h or 0.1 micrograms/mL for 24 h reduced HGLC progesterone production during exposure.”

“ Progesterone enhanced the rate of disappearance of vinblastine but did not affect 6alpha-methylprednisolone.”

“In contrast, the combined modulation of P-glycoprotein ATPase by vinblastine and progesterone reveals a non-competitive relationship between these two drugs, and hence shows that they can independently and simultaneously bind P-glycoprotein on distinct sites.”

“ Vinblastine inhibits the activation of P-glycoprotein ATPase induced by verapamil or progesterone with an inhibition constant approximately 0.5 microM in both cases.”

“ Progesterone inhibited drug binding and efflux and increased drug sensitivity to vinblastine with more potency in J7.V1-1 cells than in J7.V3-1 cells.”

“Exposure … luteal cell-containing monolayers … colchicine (100 microM), vinblastine (1 microM), and nocadazole (30 microM) resulted in a reduction in the rate of relaxin-induced plaque formation by LLCs, unequivocal evidence of an inhibitory effect of all three of these antimicrotubule agents of the rate of basal relaxin release.”

“ Progesterone also markedly inhibited [3H]vinblastine binding to membrane vesicles prepared from MDR cells, enhanced vinblastine accumulation in MDR cells, and increased the sensitivity of MDR cells to vinblastine.”

“ Vinblastine treatment blocks progesterone release from the lutein cells of superovulated immature rat ovaries, without impairing hormone synthesis, and induces the accumulation of electron-dense granules, 0.2--0.3 micron in diameter, at the juxta-sinusoidal poles of the cells.”