Hormonal control of plasminogen activator secretion in organ culture of rat ventral prostate

The usefulness of plasminogen activators (PAs) in the follow-up of the secretory function of the prostate in culture, as well as the hormonal control of these secretory proteins was studied. Organ culture of rat ventral prostate was used as an experimental model. PA secreted into the culture medium during the two weeks' culture period was of the urokinase-type in all culture conditions, as determined by zymography. The highest activities at the end of culture were found in the involuting prostate in cultures without any hormones. As the epithelial component is strongly reduced in the involuted explants, these high activities were suggested to be derived from stroma. Corticosterone (10(-7) mol/l) and insulin (80 U/l) reduced significantly the secretion of PA, and this reduction was attenuated when the favourable effect of these hormones on the maintenance of morphology and tissue weight was taken into account. Testosterone (10(-7) mol/l) increased significantly the secretion of PA in all hormone-treated cultures, which could be due to the increased secretory activity of the epithelium. Interactions between the hormones were significant, i.e. the effects of the hormone combinations were different and could not be calculated from the separate effects of these hormones. Even though the general growth and function of the prostate is strictly androgen-controlled, these results suggest that the control of PA secretion is multihormonal.