1. 1.|The mitochondrial population in hypothalamic and hypophysial brain tissue from warm (30°C) and cold (5°C) acclimated goldfish (Carassius auralus L.) was analyzed using sterological techniques.
2. 2.|It was revealed that there is a significantly larger volume density (Vv) in the cold acclimated tissue, with no significant difference in either of the surface densities (Svext and Svint) from either of the brain areas.
3. 3.|The hypothalamic brain tissue has a significantly lower specific surface (S/V) in the cold acclimated tissue but there is not a significant difference in this parameter for the hypophysial brain tissue.
4. 4.|The values for these three parameters (Vv, Svext and SVint, and S/V) indicate that mitochondria from acclimated brain tissue undergo shape changes in response to thermal stress.
5. 5.|We suggest that the shape changes may be related to the change in the phospholipid composition of the inner mitochondrial membrane with acclimation temperature.
Summary Immuno-enzyme cytochemical investigations showed that the whole amphibian pars intermedia of the hypophysis is innervated by an intercellular network of peptidergic varicose nerve fibres which contain mesotocin or (and) parts of the mesotocin molecule. The pars intermedia does not contain vasotocinergic fibres. The mesotocinergic fibres are branches of axons leaving the pituitary stalk and the neural lobe. In animals of which the hypothalamic magnocellular neurosecretory preoptic nuclei had been completely removed, the immuno-reactive mesotocinergic fibres of the pars intermedia had totally disappeared. From this result, it is concluded that the mesotocinergic fibres of the pars intermedia of the amphibian hypophysis are axons of neurosecretory perikarya located in the hypothalamic magnocellular neurosecretory preoptic nuclei.Dedicated to Professor Berta Scharrer on the accasion of her 70th birthdayThis investigation was supported by a grant from the Belgian Nationaal Fonds voor Geneeskundig Wetenschappelijk Onderzoek 相似文献
Summary The anterior pituitary gland, testes and interrenal glands of a series of young males of the teiid Cnemidophorus l. lemniscatus (L.) have been studied by light microscopy in order to correlate the changes occurring during sexual maturation. In the testes of the smallest animals, spermatogenesis does not progress beyond primary spermatocytes and there is no differentiated interstitial tissue. In medium-sized animals, spermatids and some interstitial cells appear, and in the largest lizards, spermatogenesis is completely established and Leydig cells abound. Simultaneously with the development of the testes, interrenal glands undergo great hypertrophy and hyperplasia, especially in the peripheral reactive zone. Starting in animals of intermediate size, the anterior hypophysis exhibits a considerable hypertrophy of two rostral cell types: the chromophobic corticotrophs and the acidophilic PAS-positive cells considered to be interstitiotrophs. These cells show large, vesicular nuclei and prominent nucleoli, signs of enhanced cellular activity. The hypertrophy begins in the dorso-rostral region of the gland close to the median eminence, at the site of entry of the portal vessels. This suggests a hypothalamic influence on the function of these pars distalis cells. The scattered basophilic gonadotrophs or folliculotrophs are scarce, small, and do not vary appreciably among the animals studied. The hyperactivity of corticotrophs may account for enlargement of the interrenal glands. Testicular development is apparently related to an increased activity of interstitiotrophs but to a stable level of activity in folliculotrophs.This research forms part of project No. 31.26.S1-0244 supported by the Consejo Nacional de Investigaciones Científicas y Tecnológicas. 相似文献
Hypotheses regarding the homology of the protocoel in planktonic deuterostome larvae and mesodermal structures in ontogenetic stages of cephalochordates are evaluated. The prevalent ‘classical’ hypothesis describes the protocoel as being homologous with the diverticula of Hatschek, which, on the left side, develop into the preoral pit, subsequently into Hatschek’s pit and groove (in part). This hypothesis is based mainly on the position of Hatschek’s diverticula anterior to the rest of the mesoderm during their enterocoelic origin. It is shown here that during development the mesodermal segment that develops into Hatschek’s nephridium is the most anterior one prior to formation of Hatschek’s diverticula, and this segment assumes an anteriormost position after differentiation of Hatschek’s diverticula. Additional similarities between this segment and protocoels are: (i) presence of endomesodermal cells with podocytic extensions, (ii) excretory function, (iii) relatively early ontogenetic origin, (iv) probable lack of association with nervous structures, (v) probable ectodermal origin of a portion of the canal, and (vi) position relative to the mouth opening. Therefore, homology between the protocoel and the segment that becomes Hatschek’s nephridium is proposed. It is concluded that a glandular structure homologous to the diverticula of Hatschek and anterior to the protocoel/Hatschek’s nephridium is a synapomorphy of notochordates or chordates. 相似文献
Ultrastructural and cytochemical observations on neurosecretory neurons of the rat supraoptico-posthypophyseal systems were made under experimental conditions which resulted in striking changes in the amount of neurosecretory granules and lysosomes. Attention was focused on granulolysis. At the onset of rehydration following a 4 days water deprivation, very active autophagy took place in neurosecretory axons of the neural lobe involving the marked increase in smooth endoplasmic reticulum, microvesicles and neurosecretory granules, although the latter were still very few due to previous depletion. When axonal transport was inhibited by colchicine at the onset of rehydration, granules accumulated in the perikarya while granule reloading of the neural lobe was delayed. However autophagy, although always active in axons, remained scarce in perikarya. Moreover, in the latter there was only slight evidence of crinophagy. Hypophysectomy also induced granule accumulation in the perikarya, although accompanied by little granulolysis. Images indicative of crinophagy as shown by acid phosphatase localization were few and exclusively restricted to perikarya, while autophagy occurred essentially in axons. Autophagy appeared to be the predominant process for granulolysis and might be considered here as an aspect of the general turnover of cell constituents, related to the sudden regression of hyperactivity-induced hyperthrophy, rather than as an expression of a specific regulation of an excess of secretory material. 相似文献
Many mosses of the family Splachnaceae are entomophilous and rely on flies for spore dispersal. Splachnum ampullaceum produces a yellow‐ or pink‐coloured hypophysis that releases volatile compounds, attracting flies to the mature moss. The biosynthetic sources of the visual and aromatic cues within the hypophysis have not been identified, and may be either symbiotic cyanobacteria or chromoplasts that break down lipids into volatile compounds. Here, we used transmission electron microscopy and gas chromatography‐mass spectrometry (GC‐MS) to investigate the sources of these attractants, focusing on different tissues and stages of maturation. Microscopy revealed an abundance of plastids within the hypophysis, while no symbiotic bacteria were observed. During plant maturation, plastids differentiated from amyloplasts with large starch granules to photosynthetic chloroplasts and finally to chromoplasts with lipid accumulations. We used GC‐MS to identify over 50 volatile organic compounds from mature sporophytes including short‐chain oxygenated compounds, unsaturated irregular terpenoids, fatty acid‐derived 6‐ and 8‐carbon alcohols and ketones, and the aromatic compounds acetophenone and p‐cresol. The hypophysis showed localised production of pungent volatiles, mainly short‐chain fermentation compounds and p‐cresol. Some of these volatiles have been shown to be produced from lipid oxidase degradation of linolenic acid within chromoplasts. However, other compounds (such as cyclohexanecarboxylic acid esters) may have a microbial origin. Further investigation is necessary to identify the origin of fly attractants in these mosses. 相似文献
Summary Ultrastructural examination of the posterior pituitary of the garden dormouse (Eliomys quercinus L.) was carried out at different times in the annual cycle of this hibernating rodent. Obvious differences between experimental groups have not been observed, and the results presented here must be considered as general features of the garden dormouse posterior pituitary. Neurosecretory axons and endings can be divided into two types, according to different aspects of neurosecretory granules (NSG) and microvesicles (MV). One type contains spherical NSG with homogeneous cores and round MV. In the other type, NSG have various, often elongated, shapes. Their content shows two types of crystalline structures and most of the MV have flattened aspects. As it is very unlikely that this duality in NSG is a result of an artefact of fixation, three hypotheses are presented as explanation. The duality of NSG might be related either to their hormonal content (oxytocin or vasopressin) or to their degree of maturation. Moreover, both explanations may be valid. In the species studied, pituicytes often contain concentric lamellar structures of the endoplasmic reticulum (whorls), the significance of which remains obscure.This work was supported in part by grants of INSERM (C.R.L. n 73.1091.7 and A.T.P. n 4.74.25) 相似文献
The chronological appearance of selected endocrine cells in the pituitary of African catfish Clariasgariepinus (Burchell, 1822) was studied morphologically, histologically and immunohistochemically by using antisera raised against catfish growth hormone (cgGH) and recombinant tilapia prolactin I (tPRL). cgGH- and tPRL-like immunoreactive cells were visible from day 1 post fertilisation (hatching) throughout the juvenile and the adult stage. From 1 to 90 days after hatching, the larval pituitary is oval in shape with a distinctly shaped rostral pars distalis, proximal pars distalis and pars intermedia. From day 120 onwards allometric growth of the rostral and proximal pars distalis extended the prolactin and growth hormone cells anteriorily and posteriorily, respectively. Size and activity of the prolactin and growth hormone cells, measured by the ratio of cell surface to nuclear surface remained constant until day 40 and showed a growth spurt thereafter. Growth hormone content, measured with a catfish-specific radio-immunoassay from hatching until 60 h post hatching, increased exponentially between 30 and 60 h. 相似文献