The pinealocyte of the female garden dormouse presents ultrastructural characteristics correlated with the sexual cycle. In winter, during the period of sexual quiescence, the pinealocyte is very rich in liposomes, myelinic bodies and lysosomes; the same holds during the summer quiescence state. These organelles and a great number of intracellular vacuoles are very well developed in dormice artificially maintained in anoestrous during the normal sexual activity period by light deprivation. In spring liposomes are strongly reduced in animals that are awake and sexually active, whereas the number of "synaptic ribbons" and of densecored vesicles increases. This ultrastructural aspect can be obtained during winter quiescence in animals living at 22 degrees C, under continuous light, and showing early sexual activation. If illumination is prolonged over the seasonal sexual phase dilated cisterns of granular endoplasmic reticulum, filled with proteinaceous material, appear in the cell. It seems that light no more activates, but inhibits gonadostimulator mechanisms. The pinealocyte's ultrastructural elements which are characteristic of a definite sexual state generally develop before this state is fully established. Actually, the functional significance of these organelles is not known.
The selective uptake and localization of radioactivity in the fetal male reproductive organs (epididymis, seminal vesicles and prostate) of the guinea-pig (50-60 days of gestation) after in-vivo and in-situ subcutaneous injection of [3H]oestradiol was investigated by autoradiography. In 50-day-old fetuses, the different areas of the epididymis showed selective retention of radioactivity in the nuclei of peritubular and stromal cells surrounding the epididymal duct; no retention was observed in the epididymal epithelium. A similar distribution of silver grains was observed in the 60-day-old fetus. Seminal vesicles and prostate sections from both 50- and 60-day-old fetuses showed concentration and retention of radioactivity only in stromal cells, whereas the epithelium did not exhibit silver grains. In all the tissues studied, the nuclear labelling was abolished after injection of [3H]oestradiol plus a 100-fold excess of non-labelled oestradiol. As the mesenchyme surrounding the epithelia of the epididymis, seminal vesicles and prostate were labelled selectively with [3H]oestradiol, it is suggested that during fetal life of the guinea-pig the mesenchymal stroma of these fetal male reproductive organs may be considered as a target tissue for oestrogen.
After comparison of results obtained by different modalities of 3h-5HTP injections (involving intraallantodic, intraventricular and intraperitoneal injections), the intraperitoneal one was retaineed to study experimental cytochemcal biosynthesis of indoleamines, in the epiphysis of Lacerta vivpara J., during ontogenesis. From stage 36 of embryogenesis, the selective radioautographic labelling, significant of atritiated indoleamines storage, was located in the distal part of the epiphysis. From stage 36 to 40 (just before hatching) and 3 days after hatching, microscopic and microphotometric studies point out, in the epiphysis epithelium, a highly significant increase in tritiated infoleamines rate. In contrast, the weak nonspecific reactions, in the neighbouring brain structures (dorsal telencephalon, tectum opticum and paraphysis), stay constant. The metabolism and storage sites of indoleamines belong to sensory line cells. During ontogenesis, these sites appear successively in distal, middle and proximal epiphysis and from the basal to the upper part of the sensory line cells. The embryonic parietal eye, in spite of structural analogies, does not take up the radioactive compound.
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