furnace for another 3–4 h after adding a few drops of concentrated nitric acid. The ash content of each sample was placed in a dry clean vial, dissolved in 0.5 N nitric acid with
a final volume of 7 ml and analyzed at the end of the season. Na and K concentrations were assayed by emission flame photometry, whereas Ca,
Zn, Cu and Fe were determined using atomic absorption spectrophotometry as described Ž
. Ž
. Ž
. by Clegg et al. 1981 . P Bio-Merieux, France and Mg Bayer diagnostics, Germany
were determined colorometrically using commercial kits. 2.3. Hormonal analysis
Jugular blood was collected after slaughtering into EDTA-containing vials, cen- trifuged at 1500 g for 20 min. Plasma was stored at y608C pending hormonal assays.
The concentration of testosterone was measured in duplicate in 200 ml of plasma Ž
. without column separation from dihydroxytestosterone DHT using a method previ-
Ž .
ously described by El-Belely et al. 1995 . The cross-reactivity of the antibody was 100 testosterone, 58.6 5 a-DHT, 54.3 5 b-DHT, 15.6 androstenedione, 7.8
corticosterone, and less than 1 oestriol and oestradiol 17a. The sensitivity of the assay was 10 pgrml. The average intra- and inter-assay coefficients of variation in six assays
were 13.5 and 14.2, respectively.
2.4. Statistical analyses Changes in plasma testosterone concentrations and mineral contents of different
genital organs within and between age groups were statistically evaluated by the least Ž
. squares analysis of variance using the general linear models GLM procedures of the
Ž .
statistical analysis system SAS, 1996 . Correlations between hormonal and mineral concentrations were undertaken using SAS procedures.
3. Results
The age related changes in concentrations of plasma testosterone and bulk and trace elements in the testes, epididymides and accessory glands are shown in Table 1.
Plasma testosterone concentrations increased progressively with age advancement, Ž
. Ž
. reaching its highest values mean S.E. in the mature 4.8 0.6 ngrml compared to
Ž .
Ž .
Ž prepubertal 1.1 0.1 ngrml , peripubertal 3.2 0.4 ngrml and aged 2.6 0.3 ng
. rml camels.
Ž The overall mean values of the studied minerals revealed that Na 4033.4 128.2
. Ž
. Ž
. mg ; Ca 1733.5 84.4 mg and Cu 5.3 0.5 mg were more concentrated in the
Ž .
Ž .
testes. The higher concentrations of P 6595.8 511.6 mg and Fe 4.9 0.4 mg were found in the epididymides. Prostate gland had the highest concentration of Zn
Ž .
185.5 16.3 mg , whereas bulbo-urethral gland contained the highest concentration Ž
. Ž
. of K 3798.4 253.2 mg and Mg 141.1 30.5 mg .
Statistical analyses of the data showed that there was a 3- to 4-fold increase in Na and K contents of the testes and epididymides as well as a 2-fold increase of K concentra-
tions in the prostrate and bulbo-urethral glands of the peripubertal as compared to prepubertal animals. There was a further, though less marked, increase in Na and K
Ž .
contents in all genital organs of the mature camels followed by dramatic P - 0.01
decreases in both elements in those of the aged animals. As a result of these changes in the distribution of Na and K, the Na to K ratio changed from about 2:1 in the testes and
accessory glands of those in the prepubertal age to about 9:1 in the testes and 1:4 in the accessories of peripubertal and mature animals. These ratios changed to 3:1 and 1:2,
respectively, in these organs of animals over 15 years old. The ratios of both electrolytes changed to a little over 1:1 in the epididymides of the latter camels. Moreover, the
genital organs of these animals contained 2 to 3 times greater Ca and Cu contents than found in those of the peripubertal and mature animals. The reverse was found true
Ž .
concerning P, Mg and Fe, particularly the marked decrease P - 0.01 in testicular Mg, epididymal P and Fe in the aged dromedaries. Concentration of Zn displayed a different
Ž .
pattern where testicular content decreased P - 0.05 whilst epididymal and accessories Ž
. content increased P - 0.01 in the aged compared to young and mature animals.
The interaction between plasma testosterone and minerals studied are shown in Table 2.
Concentrations of plasma testosterone were correlated significantly with the content of Na, K, Ca and Mg in all genital organs but only with epididymal content of P and
with the content of Zn in the accessory glands. Correlations between the content of the different bulk and trace elements in all genital organs included significant positive
correlations between Na and Fe as well as between Zn and Cu; and significant negative correlations between Na and each of K and Zn, Ca and each of P and Mg and between
Zn and Fe as well as Cu and Fe.
4. Discussion
