Studies on the Relationship between Some Trace-Elements and Steroid Hormones in Prostatic Disorders amongst Nigerians
No Thumbnail Available
University of Lagos
Benign hyperplasia and carninome of prostate are prostatic disorders commonly found in aging males. These diorders are reported to be less common amongst Nigerians, though there has been no concrete pathophysiological evidence to support this observation.The exact aetiology of these disorders has not been resolved, but some factors have been identified as being contributory to their development. Amongst these factors are androgenic hormonal control and the influence of some trace-elements on the metabolic activities of the gland.We investigated the interrelationship between these factors in Nigerians with a view to elucidating any physiological differences that may exist between Nigerians and other peoples. Our results showed that the extracellular hormonal millieu of the prostate gland in Nigerians is not significantly different from those of Caucasians in Europe and North America. Plasma testosterone levels in healthy Nigerians, aged between 50 and 90 years (15.5 + 0.4)nmol/1 SE) is comparable to the levels reported for caucasians of a similar age group in Germany and England. This level is also significantly higher than the levels in age-matched cancer patients (10.9 + 0.7) nmol/1) (P<0.001), but not significantly different from the levels in age-matched BPH patients (14.9 + 0.4 nmol/1 SE: P>0.10). Levels of other androgens were not different between the three groups. Plasma levels of zinc were higher in BPH subjects and lower in cancer patients compared wih healthy controls, while plasma cadmium was higher in cancer patients. Intraprostatic DHT was elevated in hyperplastic tissues (4.9 + 0.2 ng/g) relative to normal tissues (1.7 + 0.18 mg.g) ad malignant tissues (1.7 + 0.2 ng/g). In contrast, testosterone and A-Dione were found in greater concentration in malignant tissues (7.9 + 0.6 ng/g and 4.6 + 0.3 ng/g respectively) than in BPH (0.5 + 0.3 ng/g; 0.2 + 0.01 ng/g and normal tissues 0.3 + 0.05 ng/g; 0.2 + 0.03 ng/g). Zinz was significantly concenrtrated in hyperplastic tissues (17.9 + 0.6 umol/g or 1170 + 39.2 ug/g) and Normal tissues (12.1 + 0.8 umol/g; 791 + 55.5 ug/g) than in malignant tissues 2.9 + 0.4 umol/g; 189.6 + 26.1 ug/g). A greater proportion of zinc and DHT were located in the nuclear fraction of hyperplastic tissues. In contrast, the cytoplasmic concentration of zinc was inversely proportional to DHT concentration in these tissues. Cadmium accumulated more in malignant tissues (28.9 + 0.37 nmol/g) compared with normal 3.8 + 0.63 nmol/g) and hyperplastic tissuess (14.6 + 1.1 nmol/g). The results suggest an interrelationship between the concentration of zinc and accumulation of DHT, especially in the nucleus of hyperplastic tissues. Results of in vitro experimental studies involving additions of varying concentrations of exogenous zinc and cadmium aptly supported the above findings. Additions of low concentration (10-5 to 10-12M) of exogenous zinc enhanced the activities of 5 & reductase and 3 & hydroxy-steroid dehydrogenase (Reductase) in the conversion of testosterone to DHT and DHT 3 & diol in hyperplastic tissues, whereas concentrations higher than 10-5M inhibited the reaction. Similar results but to a lesser degree were obtained with carcinomatous tissues. Experiments with cadium also showed similar efefcts on the transformation of testosterone to DHT. This study shows the intracellular and extracellular hormonal environments of the prostate gland in Nigerians are not different from that of Europeans. However, the interrelationship between plasma and tissue concentrations of zinc and androgens appears to affect the levels of androgens available to the prostate, which in turn could promote or prevent the processes culminating in prostatic disorders.
Full Text Attached
Prostatic disorders , Steroid Hormones
Ogunlewe.O. J. (1986) Studies on the Relationship between Some Trace-Elements and Steroid Hormones in Prostatic Disorders amongst Nigerians. University of Lagos School of Postgraduate Studies Phd Clinical Pathology Thesis and Dissertation Abstracts, 165p.