THE EFFECTS OF SPINAL-CORD INJURY ON THE STATUS OF MESSENGER-RIBONUCLEIC-ACID FOR TRPM-2 AND ANDROGEN RECEPTOR IN THE PROSTATE OF THE RAT

The prostate is one of the male accessory sex glands that produce flui d components of the seminal plasma. in addition to androgen, a normal innervation of the prostate is believed to be important for maintainin g normal function of the prostate. Previously we noted that, in the ra t, the weight of the prostate decreased following surgically induced s pinal cord injury (SCI). This observation suggests that growth, and po ssibly function, oi the prostate may be compromised after SCI. To expl ore this possibility, we examined the effects of SCI on the androgen-r elated biochemical properties and morphology of the prostate in the ra t at various times after surgically induced SCI. SCI resulted in an ac ute decrease in prostate weight and an increase in steady state level of mRNA for testosterone-repressed prostate message 2 (TRPM 2) during the first 2 weeks postinjury, These changes perhaps relate to an incre ase in cell death or a decrease in secretory activity due to an acute suppression of serum testosterone after the injury. Concomitantly, the re was a transient, but significant, decrease in the steady state leve l of androgen receptor (AR) mRNA in the prostate during the first 2 we eks after SCI, an indication of an altered autoregulation of AR by its own ligand. Despite the fact that growth of the prostate, as indicate d by weight increase, in SCI rats resumed 2 weeks postinjury, prostate weights were persistently lower in SCI rats than sham-operated contro ls for at least 3 months. Furthermore, prostate TRPM 2 mRNA levels rem ained elevated throughout the recovery period even after a normal pros tate weight had been restored. In addition, a decrease in the height o f ventral prostate epithelial cells was noted in SCI rats 28 and 90 da ys postinjury. These results demonstrate a prolonged effect of SCI on prostate function. These findings and our unreported observation of pe rsistently smaller seminal vesicles in the same groups of SCI rats sug gest that functions of male accessory sex glands may also be compromis ed after SCI. These changes may affect biochemical properties of the s ecretory products of these glands and may provide same explanation for the reported changes in the composition of the seminal plasma and abn ormal sperm motility seen in the semen of SCI men.