HORMONAL-REGULATION OF SULFATED GLYCOPROTEIN-1 SYNTHESIS BY NONCILIATED CELLS OF THE EFFERENT DUCTS OF ADULT-RATS

The objective of this study was to define the factors regulating the e ndogenous production of sulfated glycoprotein-1 (SGP-1) in nonciliated cells of the efferent ducts. To this end we examined five different g roups of animals undergoing the following experimental procedures: (1) hypophysectomized animals at 7, 14, and 28 days, (2) 7-day hypophysec tomized rats receiving testosterone implants given at various time int ervals thereafter, (3) castration at various time intervals up to 7 da ys, (4) 7-day castrated rats receiving testosterone implants at variou s time intervals thereafter, and (5) castrated rats given testosterone implants immediately after castration and sacrificed at different tim e intervals thereafter. Efferent ducts were fixed by perfusion with 4% paraformaldehyde and 0.5% glutaraldehyde in phosphate buffer for quan titative immunocytochemical analysis at the level of the electron micr oscope. For each experimental condition and their controls, the number of gold particles/mu m(2) within the endosomal and lysosomal compartm ents was calculated taking into account the changes in both the volume of the cell and organelles being quantified and expressed as labeling content. The results revealed that hypophysectomy (up to 4 weeks) cau sed a marked significant decrease in the SGP-1 labeling content of the endosomal and lysosomal compartments. The labeling content of the lys osomal compartment of efferent ducts from rats castrated for up to 1 w eek did not change significantly. However, there was a significant dec rease in the labeling content of endosomes. This decrease is due to SG P-1, which is secreted by Sertoli cells, not being available for uptak e in the efferent ducts. These results suggested that testosterone is not required for maintaining the high labeling content of SGP-1 within lysosomes of nonciliated cells, but that a pituitary factor appears t o be needed. The administration of testosterone at different intervals to 7-day castrated animals resulted in a significant decrease of lyso somal SGP-1, suggesting that testosterone under these experimental con ditions inhibits the production of a pituitary factor that maintains t he high labeling content of SGP-1 within lysosomes of the nonciliated cells. Testosterone administered to 7-day hypophysectomized animals ov er a 24-hr period had no effect on the labeling content of SGP-1 withi n lysosomes. However, the administration of testosterone to animals im mediately following castration showed no differences in the labeling c ontent of SGP-1 within compared to controls. Together these results su ggest that the labeling content of SGP-1 within lysosomes of nonciliat ed cells of the efferent ducts is not dependent on luminal or circulat ing androgens, nor is it dependent on a testicular factor entering the lumen of the ducts. It does appear, however, that SGP-1 synthesis and targeting to secondary lysosomes is dependent on a pituitary factor t hat may have a direct or an indirect effect on the nonciliated cells. (C) 1995 Wiley-Liss, Inc.