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The sites of action and the physiological role of estrogens and progesterone in the ovary are poorly understood in Reptiles. We have undertaken a systematic study of the immunoexpression of classical oestrogen receptor (ER or ERalpha) and progesterone receptor (PR) in the female lizard during the reproductive cycle. During vitellogenesis, ER was not expressed in vitellogenic follicles whereas PR was weakly detected in the nucleus of some follicular cells and well expressed in the internal theca cells. The follicular and theca cells were immunopositive for ER in the previtellogenic follicles, the signal in both was cytosolic. PR was strongly expressed in the follicular cells, the signal was localised in the nucleus. In the post-reproductive period, ER was detected in the previtellogenic follicles in the same manner as in the breeding period. The staining for PR was expressed in both the nucleus and cytoplasm of follicular cells and theca cells. In the sexual rest, the previtellogenic follicles were all negative for ER and PR immunoexpression. These findings suggest that the main action of estrogens in the ovary is not mediated by ER. The expression of cytosolic PR only in the post-reproduction period, at the same time at the progesterone synthesis, supports the hypothesis which stipulates an exclusive nuclear localization in the absence of progesterone.

The sites of action and the physiological role of estrogens and progesterone in the ovary are poorly understood in Reptiles. We have undertaken a systematic study of the immunoexpression of classical oestrogen receptor (ER or ERalpha) and progesterone receptor (PR) in the female lizard during the reproductive cycle. During vitellogenesis, ER was not expressed in vitellogenic follicles whereas PR was weakly detected in the nucleus of some follicular cells and well expressed in the internal theca cells. The follicular and theca cells were immunopositive for ER in the previtellogenic follicles, the signal in both was cytosolic. PR was strongly expressed in the follicular cells, the signal was localised in the nucleus. In the post-reproductive period, ER was detected in the previtellogenic follicles in the same manner as in the breeding period. The staining for PR was expressed in both the nucleus and cytoplasm of follicular cells and theca cells. In the sexual rest, the previtellogenic follicles were all negative for ER and PR immunoexpression. These findings suggest that the main action of estrogens in the ovary is not mediated by ER. The expression of cytosolic PR only in the post-reproduction period, at the same time at the progesterone synthesis, supports the hypothesis which stipulates an exclusive nuclear localization in the absence of progesterone.

Our interest in the testicular study of the desert rodent, Gerbillus tarabuli, would provide a better comprehension of the seasonality of spermatogenesis in rodents. We thus performed a biometric, histomorphometric and statistical analyses in Gerbillus tarabuli sexually immature and adult during the annual reproductive cycle (active and regressed states of gonadal activity). For that, fixed testes were embedded in paraffin. Sections were stained using the modified Heidenhain Azan and then were subjected to morphometric measurements at the light microscopic level. The biometric study revealed a positive correlation between the body weight and the maturity state only, with an average of 20.8 ± 2.92 g in sexually immature Gerbils, 37.40 ± 1.86 g in the sexually quiescent adults (p <.01) and 40.40 ± 2.98 g in the sexually active adults (p >.05), while the testes weight (sexually immatures = 0.02 ± 0.003 g, sexually quiescent adults = 0.13 ± 0.01 g; p <.001 and sexually active adults = 0.27 ± 0.01 g; p <.001) and the gonadosomatic index (sexually immatures = 0.09 ± 0.02%, sexually quiescent adults = 0.36 ± 0.04%; p <.01 and sexually active adults = 0.68 ± 0.07%; p <.01) varied according to the maturity state and as well as to the season in the adults. Through the histomorphometric study, the tubular diameter showed a continuous increase from sexually immature Gerbils (72.83 ± 7.57 μm) to sexually quiescent adults (99.45 ± 4.34 μm) p <.05 then to sexually active adults (182.58 ± 5.22 μm); p <.001, this is explained by the appearance of a large lumen after puberty in the quiescent (26.32 ± 1.28 μm); p <.001 and the enlargement of the seminiferous epithelium in actives (75.11 ± 1.81 μm); p <.001. Besides, the nucleo‐cytoplasmic ratio of Leydig cells (sexually immatures = 0.5 ± 0.02) diminishes significantly after puberty in the rest period (0.42 ± 0.03); p <.05 and then during the active period (0.24 ± 0.01); p <.001. These striking biometric and morphometric differences in Gerbillus tarabuli testis between sexually immature Gerbils, sexually quiescent and active adults, follow the photoperiod‐induced changes in endocrine and exocrine functions and prove that Gerbillus tarabuli is a useful model to study histo‐physiological relationships in the testis in order to develop a more complete understanding of spermatogenesis phenomenon. [ABSTRACT FROM AUTHOR]

Testicular function in the sand rodent Psammomys obesus is subjected to seasonal alternations with a trigger of spermatogenesis in winter and a total quiescence which extends from late spring to summer. The aim of this study was to investigate the distribution of b-endorphin in the testis at the period of winter sexual activity and at its summer regression, and assess the effect of 17 ß-estradiol treatment on testicular morphology and b-endorphin expression.~Introduction~Background~The adult males were grouped into 4 groups (rest group, sexually active group, rest treated with 17ß-estradiol group and controls at sexual rest injected with olive oil, n = 5 in each group). Using anti-serum against b-endorphin, we studied its testicular expression by Western blot and cellular location by immunohistochemical (IHC) method, respectively.~Material and Methods~Methods~We detected by Western blot a peptide of 3.5 kDa molecular weight corresponding to b-endorphin only in sexually resting and control males. The 17ß-estradiol treatment induced a clear reduction in the b-endorphin band expression compared with the latter. These results were confirmed by the IHC analysis since b-endorphin was only observed in the testis at sexual rest and in controls, in majority of seminiferous tubules at the level of germ cells. The intensity of IHC labeling was significantly different between spermatogonia and spermatocytes I or round spermatids which revealed the strongest labeling. The intense immunoreactivity was also located in Leydig cells and highly significantly varied compared to the germ cells. The 17 ß-estradiol treatment decreased significantly the ß-endorphin signal in germ cells but not in Leydig cells.~Results~Results~The 17ß-estradiol treatment induces a repressive effect on seasonal testicular endorphinergic system in P. obesus and this action targets exclusively the germ cells.~Conclusion~Conclusions [ABSTRACT FROM AUTHOR]

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In Mammals, opioid peptides are involved in various physiological processes including the reproductive function. The knowledge of the distribution of β-endorphin, one of opioid peptides in Reptiles ovaries is very limited. Therefore, the present study used the lizard ovarian follicles to further elucidate the role of this peptide in steroidogenesis. In Uromastyx acanthinura, the localization of both this peptide and sex steroid hormone was investigated by the immunohistochemical approach. This technique was used to evaluate the distribution of these substances and their relationship. The β-endorphin is strongly distributed in the granulosa cells and oocyte cytoplasm of the previtellogenic follicles in sexually quiescent lizards (winter) when steroidogenesis was interrupted. In spring, the signal became weak, or even absent, in the vitellogenic and previtellogenic follicles. The granulosa cells of the previtellogenic follicles showed an important synthesis of 17β-estradiol. Females that did not undergo in vitellogenesis in spring showed the same profile than quiescent females of winter. These findings represent the first evidence of the presence of β-endorphin in the ovary of this lizard. The seasonal variations observed in the reproductive cycle suggest that this opioid peptide is involved in the modulation of seasonal steroidogenesis. [ABSTRACT FROM AUTHOR]

In Mammals, opioid peptides are involved in various physiological processes including the reproductive function. The knowledge of the distribution of beta-endorphin, one of opioid peptides in Reptiles ovaries is very limited. Therefore, the present study used the lizard ovarian follicles to further elucidate the role of this peptide in steroidogenesis. In Uromastyx acanthinura, the localization of both this peptide and sex steroid hormone was investigated by the immunohistochemical approach. This technique was used to evaluate the distribution of these substances and their relationship. The beta-endorphin is strongly distributed in the granulosa cells and oocyte cytoplasm of the previtellogenic follicles in sexually quiescent lizards (winter) when steroidogenesis was interrupted. In spring, the signal became weak, or even absent, in the vitellogenic and previtellogenic follicles. The granulosa cells of the previtellogenic follicles showed an important synthesis of 17beta-estradiol. Females that did not undergo in vitellogenesis in spring showed the same profile than quiescent females of winter. These findings represent the first evidence of the presence of beta-endorphin in the ovary of this lizard. The seasonal variations observed in the reproductive cycle suggest that this opioid peptide is involved in the modulation of seasonal steroidogenesis.