Immuno-enzyme cytochemical demonstration of mesotocinergic nerve fibres in the pars intermedia of the amphibian hypophysis

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     

Ligh- and electron-microscopic immunocytochemistry of somatotropes in the anterior pituitary gland of European ferret,Mustela putorius furo

Light-microscopic immunocytochemistry of ferret anterior pituitary revealed the localization of somatotropes in the pars distalis, but no immunoreactive cells were detected in the pars tuberalis. Ultrastructural studies by superimposition immunocytochemistry and immuno-electron microscopy, clucidated the morphological heterogeneity of these somatotropic cells. They were classified into 2 subtypes on the basis of size of the secretory granules. Type-I cells with small granules (mean diameter, 192 nm), were considered to be the immature somatotrop, while Type-II cells, with comparatively larger secretory granules (mean diameter, 257 nm), were considered to be the matured form of Type-I cells and the typical somatotropic cell-type, and were much more predominant than the Type-I cells. The fact that Type-II cells had a distinct Golgi zone and many mitochondria, while in Type-I cells the intracellular organelles were generally less developed, supports this suggestion. In addition to these two extreme subtypes, several intermediate forms were also encountered that may represent different transitional phases during the conversion of Type I to Type II. Protein A-gold immuno-electron microscopy illustrated the specific localization of growth hormone over the granules, with no labelling over any other cytoplasmic organelles of the 2 somatotrope subtypes.     

The circadian system and melatonin: lessons from rats and mice

The circadian system (CS) comprises three key components: (1) endogenous oscillators (clocks) generating a circadian rhythm; (2) input pathways entraining the circadian rhythm to the astrophysical day; and (3) output pathways distributing signals from the oscillator to the periphery. This contribution briefly reviews some general aspects of the organization of the rodent CS and pays particular attention to recent results obtained with various mouse strains, related to molecular mechanisms involved in entraining the endogenous clock and the role of the pineal hormone melatonin as a hand of the endogenous clock.     

Evidence for circadian-based photoperiodic timekeeping in Svalbard ptarmigan,the northernmost resident bird

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Ultrastructural features of the developing hypothalamo-hypophysial axis in the rat

Summary Nerve fibres containing granular vesicles first appear in the median eminence of the rat on the 16th foetal day while secretory granules in the cells of the adenohypophysis are not present till the 17th foetal day. These observations suggest that the differentiation and early activity of pars distalis cells may depend on substances elaborated at nerve terminals in the median eminence. Although the loops of the primary plexus of portal vessels do not develop until the 4th postnatal day, substances released by nerve fibres in the neurohypophysis could reach the pars distalis through vessels already present at the 15th foetal day in the mesenchyme between the diencephalon and the adenohypophysis. This view is supported by the fact that the earliest cells to exhibit ultrastructural evidence of secretory activity are in the rostral pole of the pars distalis, the first region of the gland to become vascularized. The earliest granules to appear in the cells of the pars distalis correspond to those which are considered to contain mucoprotein hormones; somatotrophin type granules were seen only in postnatal tissues.The finding that, in the median eminence, the development of granular vesicles precedes that of agranular vesicles is discussed with reference to the times at which neurosecretory materials and monoamines become detectable in the region.We should like to thank Miss Ann Pearson, Mr. D. Burns, and Mr. J. Nailon for their technical assistance, and Mr. J. Simmons, F.R.P.S., for his help in the preparation of illustrations. This work was supported by grants from the National Health and Medical Research Council of Australia.     

Corticotrophic cells in the rostral zone of the pars intermedia and in the adjacent neurohypophysis of the rat and mouse

Summary In the mouse, the rostral zone of the pars intermedia is almost exclusively composed of typical corticotrophic cells. They are located around and even within the neural stalk, at the level of transition between stalk and neural lobe. In the rat, the corticotrophic cells of the rostral zone are found in scattered islets among the MSH producing cells, and also in the neural lobe. In both the rat and mouse, these cells are in direct contact with various types of nerve terminals. Synaptoid contacts with aminergic and neurosecretory nerve fibers are observed. Furthermore they are also closely related to the hypophysial portal vessels. Following adrenalectomy, the cells located in the neurohypophysis always react more intensely than tose in the rostral zone. The functional significance of these corticotrophic cells which are subject to both humoral and neural regulation remains as yet hypothetical. Their participation in neurogenic stress response seems probable.     

Immunohistochemical localization of adrenocorticotropin and melanocyte stimulating hormone in pars intermedia of rat hypophysis

Summary The sites of production of adrenocorticotropin (ACTH) and melanocyte stimulating hormone (MSH) are studied by the immunoglobulin-peroxidase bridge technique, using antisera prepared against synthetic porcine 1–24 and 17–39 ACTH, and bovine MSH on the rat adenohypophysis. Presence of ACTH all over the pars intermedia (PI) is indicated by staining with antisera _p 1–24 and _p 17-3-9 ACTH. There are darkly stained ACTH cells in the PI and pars tuberalis (PT), similar to those in the pars distalis (PD). With higher dilutions of the ACTH antiserum, staining intensity disappears or reduces markedly in majority of the PI cells, whereas, the ACTH cells in the PI, PD and PT do not vary much in their staining intensity. Therefore, it is concluded that majority of the PI glandular cells (light glandular and dark cells) contain less corticotropin than the ACTH cells. From these observations, it seems to me that the major amount of corticotropin is supplied by the ACTH cells of the PD, PI and PT, and less by the light glandular and dark cells of the PI. The antiserum is ineffective after absorption, so the staining reaction appears to be specific for _p 1–24 and _b 17–39 ACTH.Presence of MSH all over the PI is indicated by staining with antisera to bovine MSH. Majority of the PI cells are highly stained even with higher dilution of the antiserum. The unstained cells in the PI seem to be ACTH cells and/or marginal cuboidal cells. The antiserum was ineffective after absorption, so the staining reaction appears to be specific for _b MSH.Control over the PD corticotropin through the median eminence portal circulation and the PI and PT control through nervous system is also discussed.This study was supported by MRC of Canada Grant nos. MA-3759, and MA-5160.The author gratefully wishes to thank Drs. P. Desaulles and W. Rittel (CIBA, Basle, Switzerland) for the synthetic _p 1–24 ACTH and _b MSH, Dr. R. F. Phifer for _p 17–39 ACTH, and Dr. S. S. Spicer for providing samples of rabbit anti-porcine 17–39 ACTH and anti-human ACTH sera, Drs. George Sétáló and Paul Nakane for their valuable advice. He also acknowledges the help of Mr. Shankar Nayak to prepare the antisera and the skilful technical assistance of Miss. Elise Poiré.     

Structural changes in the pars intermedia of the cichlid teleost Sarotherodon mossambicus as a result of background adaptation and illumination

Summary The pars intermedia of Sarotherodon mossambicus contains two structurally different endocrine cell types. The predominant cell type is assumed to synthesize MSH and related peptides. The second cell type is PAS positive; its function and products are unknown. In this second cell type changes occur in relation to background colour and illumination. Thus, PAS positive cells of fish adapted to a white background are less numerous and metabolically less active than those of fish adapted to a black background, and are most active in fish kept in total darkness. In blinded fish, whether in light or in darkness, the activity of the PAS positive cells is similar to that of the black background-adapted animals. The significance of these responses in relation to the control of background adaptation is discussed.     

贝伐单抗辅助的23G玻璃体切割术治疗严重增生性糖尿病视网膜病变的疗效观察

目的：2011年,我国糖尿病患者人数高达9240万。糖尿病视网膜病变（diabeticretinopathy,DR）作为糖尿病患者的常见并发症,在糖尿病人群中的患病率为37％,是导致成人获得性盲的最主要原因之一。严重增生性糖尿病视网膜病变以牵拉性视网膜脱离、玻璃体出血为特征,具有致盲率大,手术难度高等特点。针对与此,本文主要探讨术前注射贝伐单抗对23G玻璃体切割手术治疗严重增生性糖尿病视网膜病变患者效果的影响。方法：回顾性病例对照研究。共收集严重增生性糖尿病视网膜病变患者70例,药物辅助手术组（A组）21例,术前3—7天行玻璃体腔注射贝伐单抗（1．25mg／O．05mL）;单纯手术组（B组）49例,行23G玻璃体切割术。分析两组术前及术后视力、手术时间、医源性裂孔、电凝、术后出血的不同。结果：在术后3月,两组视力提高有统计学意义（P〈O．05）。A组平均手术时间为74分钟,而B组平均手术时间为85分钟（P〉0．05）。医源性裂孔在A组中有1例,而B组中有16例（P〈0．05）,在A组中有3例使用电凝,B组中有25例使用电凝（P〈0．05）。A组有1例出现术中及术后出血,B组为20例（P〈O．05）。结论：在这个回顾性研究中,我们发现对于严重增生性糖尿病视网膜病变的病人,术前玻璃体腔注射1．25mg／O．05ml贝伐单抗可以显著减少医源性裂孔的发生,减少术中电凝使用及术中术后出血的发生。