Histo-physiology of the epididymis of spiny-tailed lizard, Uromastix hardwicki, a seasonal breeder, has been studied during the annual reproductive cycles. Histo-architechture of the duct seems composed of four cell types instead of two: Principal, basal clear and halo cells. based on mammalian criteria of identification. Cellular quantification revealed alteration only in principal and basal cell types Le (85.2% and 7.3%) during fertile phase and 79.1% and 14% respectively during the regressed phase. Clear and halo cells showed no variation. Secretory activity of the duct was exhibited throughout the duct varying with respect to the reproductive phase. L/M of the duct demonstrated correlation of tubular diameter and epithelial cell height with different phases of reproductive cycle: values being lowest during the regressed phase and gradually increasing through maturational and fertile phases. These parameters characteristically demarcated the duct into three regions; Proximal, distal and caudal. Epithelial cell height. was maximum in the middle region and minimal in posterior region and the lumen diameter of the duct increased markedly from anterior to posterior region; regionalization is supported by corresponding protein profiles analysed by SDS-PAGE.
Protein profiles were analysed by both Non-SDS and SDS-PAGE. The data on epididymal weight, protein content and electrophoretically separated proteins obtained during the complete annual reproductive cycle is presented. The duct weight correlates well with the secretory activity of the duct. Despite overlap of many proteins secreted during the different phase of reproduction, few were identified characteristically being secreted during a particular phase of reproduction and hence an attempt was made to relate some of these with sperm maturational function of the duct during the particular phase. Thus the seasonal effect on protein profiles of the duct has been studied.
Histologically observed peak secretory activity coincides with the maximum number of protein bands which appeared as one protein band of high molecular weight (> 66 Kd and protein band 7 with mol. wt. < 45 Kd from November to April. The duct weight decreased in May following a sudden regression in diameter and epithelial cell height of the duct. The secretory activity of the lizard epididymis showed a decrease both in the number as well as in the intensity of some specific protein bands from May to October. Two protein bands no. 1 and 2 of high mol. wt. (> 66 Kd) and protein bands 4, 6, 7 and 9 having mol. wts. > 60, < 50, < 45 and 34.7 Kd were not observed during May and June An attempt has been made to characterize the different phases with respect to epididymal proteins. It may appear that multiplicity rather than a select few of these proteins sperm interaction occur in epididymis. Moreover the observeration of protein profiles in different regions of epididymis revealed that the differences between regional protein profiles may be due to differences in epithelial cell protein secretion between regions. Thus substantial differences In protein pattern from different epididymal regions could be detected.
Testosterone concentration in the plasma were also measured by radioimmuno-assay during different phases of the annual cycle to correlate with epididymal proteins. The highest peak observed during fertile phase decreased greatly to reach minimum levels during the regressed phase of reproductive cycle.
Finally, effect of mammalian gonadotrophins (FSH, HMG, PMSG, HCG and LH) and sex steroids (testosterone and progesterone) on Sexually regressed epididymis was also investigated. Both histological and electrophoretic studies revealed that only FSH seemed to induce a significant increase in weight, diameter of the lumen and epithelial height of the duct; electrophoretic seperation of protein bands showed reappearance of protein bands 1 and 7 with mol. wt. > 66 and < 45 Kd after the injection of HMG during the inactive period of reproduction. FSH/HMG was more potent than PMSG, HCG and LH in bringing about hypertrophy of the duct. Testosterone failed to initiate protein band 7 « 45 Kd)but progesterone seemed to affect this band.
The histological changes alongwith protein profiles alterations during various reproductive phases, as well as under gonadotrophins and sex steroid administration were discussed to evaluate the regulation of duct function. The evidence suggests that FSH-like
Molecule in comparison to testosterone predominantly is involved in the functional integrity of the duct in this species and further that the structural and functional properties of different region of the
duct may have multifactorial regulation and control (additional controlling factors including temperature and other than andrgens).