Estrogen receptor a Estrogen receptor b Progesterone receptor Lizard Reptile Mots cle´s : Vitellogene `se Re ´cepteur des oestroge `nes a Re ´cepteur des oestroge `nes b Re ´cepteur de la progeste ´rone Le ´zard Reptile

Abstract: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.

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.

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