scholarly journals Histogensis of the Pars Nervosa in Buffalo

2008 ◽  
Vol 1 (1) ◽  
pp. 22-28
Author(s):  
H. Attia
Keyword(s):  
Pars Nervosa

Secretory Elements of the Pars Nervosa of the Pituitary

Nature ◽  
1938 ◽  
Vol 141 (3563) ◽  
pp. 286-286 ◽  
Author(s):  
MERVYN GRIFFITHS
Keyword(s):  
Pars Nervosa

scholarly journals THE STRUCTURE AND DIFFERENTIATION OF THE SPECIFIC CELLULAR ELEMENTS OF THE PARS INTERMEDIA OF THE HYPOPHYSIS OF THE DOMESTIC PIG

1922 ◽  
Vol 36 (1) ◽  
pp. 141-156 ◽  
Author(s):  
Siegfried Maurer ◽  
Dean Lewis
Keyword(s):  
Third Ventricle ◽  
Pars Intermedia ◽  
Posterior Lobe ◽  
Domestic Pig ◽  
Pars Nervosa ◽  
Thin Membranes ◽  
Pituitary Secretion ◽  
Mechanical Separation ◽  
First Time ◽  
Fetal Pig

The bearing of these results on the Herring-Cushing theory of pituitary secretion is apparent. For the first time a true secretion antecedent has been demonstrated in the cells of the pars intermedia, an antecedent which appears in the cells at the same period of development at which active pressor effects may be obtained from the gland extracts. The route of export of this material from the gland to its point of utilization, however, is unknown; it may go by way of the blood or, as required by the Herring theory, by the transneural route to the third ventricle. The objections to the latter conclusion have been amply expanded in the introduction to this paper, but here may be emphasized the fact that the fetal pig hypophysis contains no hyaline bodies. Indeed they are rare in the adult, though there may be seen in the cells of the pars nervosa in the processes of its intrinsic cells, granular deposits which we believe to be the antecedents of the hyaline bodies but which in the pig rarely are discharged and aggregated into discrete masses as in other mammals. The fact that some observers have obtained positive pressor effects from the nervous part of the posterior lobe, exclusive of the pars intermedia, need not weigh very heavily in attempting to trace the course of the secretion, when we reflect that the difficulties of making such a mechanical separation are almost insuperable, and that the chemical product of the pars intermedia is so soluble and vanishes from the cells so rapidly that it may well be diffusible through the thin membranes which intervene and penetrate post mortem into adjacent parts. We are inclined, therefore, to the view that the secretion leaves the gland by the vascular route rather than by way of the interfibrillar spaces of the pars nervosa.

The pars nervosa of the bovine hypophysis

1930 ◽  
Vol 50 (2) ◽  
pp. 505-519 ◽  
Author(s):  
Paul C. Bucy
Keyword(s):  
Pars Nervosa

Expression, distribution, regulation and function of IGFs in the ovine fetal pituitary

1995 ◽  
Vol 14 (3) ◽  
pp. 323-336 ◽  
Author(s):  
F Lü ◽  
K Yang ◽  
V K M Han ◽  
J R G Challis
Keyword(s):  
Pituitary Gland ◽  
Endocrine Cells ◽  
Cell Types ◽  
Pars Intermedia ◽  
Pars Distalis ◽  
Paracrine Factors ◽  
Pomc Mrna ◽  
Pars Nervosa ◽  
Igf I ◽  
And Function

ABSTRACT Activation of the fetal pituitary-adrenal axis is crucial for fetal organ maturation and the onset of parturition in sheep. Many factors including corticotrophin-releasing hormone (CRH) and arginine vasopressin secreted from the hypothalamus, and growth factors produced within the pituitary may be involved in the regulation of maturation of the fetal pituitary gland. IGFs have mitogenic and differentiation-promoting capacities in a variety of organs and are synthesized as paracrine factors within developing tissues. However, there is little information concerning the synthesis, distribution, regulation and function of IGFs in the fetal pituitary gland at different times during pregnancy. Therefore, we have localized IGF-I and IGF-II mRNAs and peptides, and determined the effect of cortisol on the level of IGF-II mRNAs in the pituitary glands of developing sheep fetuses. We examined the possible effects of IGFs on corticotroph function in cultures of adenohypophysial cells from term fetuses. Seven species of IGF-II transcripts of 1·2–6·0 kb were identified by Northern blot analysis in the pituitary gland of fetuses between day 60 of gestation and term (day 145). The levels of IGF-II mRNAs did not change significantly during pregnancy, although there was a trend for the presence of higher levels of IGF-II mRNAs at day 60 of gestation. IGF-I mRNA was not detectable. By in situ hybridization, IGF-II mRNA was localized to non-endocrine cells and to cells lining the blood vessels of the pars distalis, to some presumed endocrine cells in the pars distalis and pars intermedia, and to clusters of cells in the pars nervosa. In contrast, IGF-I and IGF-II peptides were detected in the presumed endocrine cells in the pars distalis and pars intermedia but not in the pars nervosa. Incubation of adenohypophysial cells from term fetuses with IGF-I, but not IGF-II, for 48 h increased specific 125I-Tyr-ovine CRH binding. However, neither IGF-I nor IGF-II had any significant effects on the basal or CRH-stimulated immunoreactive (ir)-ACTH output, the level of POMC mRNA or the number of ir-ACTH positive cells. Infusion of cortisol to fetuses starting at day 96 of gestation for 100 h or at days 120–125 of gestation for 84 h did not affect the level of IGF-II mRNAs in the pars distalis but decreased the levels of POMC mRNA. These results are consistent with IGFs having the potential to influence fetal pituitary function, although probably on cell types other than the corticotrophs. The likely sources of IGFs may be predominantly local (IGF-II) or from extrapituitary sources (IGF-I).

Introductory remarks (second day): neurosecretion

1971 ◽  
Vol 261 (839) ◽  
pp. 389-390 ◽  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Peptide Hormones ◽  
Sinus Gland ◽  
Endocrine Activity ◽  
Corpora Cardiaca ◽  
Pars Nervosa ◽  
The Central Nervous System ◽  
The Brain

Our session today needs few words of introduction, for most of the foundations for our programme this morning have already been laid during the papers and discussions yesterday. It is perhaps only in relation to the secretory activities of neurons (which we shall discuss later this morning), and in particular the use of the term ‘neurosecretion’ that some comments of mine might be appropriate and useful. For many years those of us who are interested in the field of neuroendocrinology have appropriated the word ‘neurosecretion’ to describe certain specific elements in the central nervous system which appear to be engaged in endocrine activity. The earliest of these specialized neurons to be described, namely those tracts linking the hypothalamus and pituitary pars nervosa in vertebrates, and those linking the brain and the sinus gland in crustaceans and the corpora cardiaca of insects, were clearly distinguishable by histological means from other neurons. Moreover, in terms of function and biochemistry also these classical neurosecretory systems seemed to have distinct characteristics. Unlike other neurons they released peptide hormones into the bloodstream and this, and some other features, formed the basis for the original neurosecretion concept proposed by Scharrer and Bargmann.

scholarly journals Adaptation of Camelus dromedarius pars nervosa of the hypophysis to winter and summer living conditions

2012 ◽  
Vol 50 (2) ◽  
pp. 203-212 ◽  
Author(s):  
Fatma Zohra Djazouli Alim ◽  
Manuel Jose Rodríguez ◽  
Carmen Andrade ◽  
Nemcha Lebaili ◽  
Nicole Mahy
Keyword(s):  
Living Conditions ◽  
Camelus Dromedarius ◽  
Pars Nervosa

The developmental endocrinology of the spleen in chick embryos

Development ◽  
1970 ◽  
Vol 24 (2) ◽  
pp. 357-365
Author(s):  
T. W. Betz
Keyword(s):  
Chick Embryo ◽  
Growth And Development ◽  
White Pulp ◽  
Chick Embryos ◽  
Pars Distalis ◽  
Liver Growth ◽  
Body Weights ◽  
Pars Nervosa ◽  
Splenic White Pulp ◽  
Red Pulp

Partial decapitation (‘hypophysectomy’) of the chick embryo significantly reduces body growth by 20 days (stage 46 −) of incubation as indicated by body weights, 60% of normal; the lengths of the toe and tibiotarsus, 80% and 78% of normal respectively; and liver growth, 47% of normal, but the gall bladder was not apparently enlarged. It significantly increases spleen growth to 82 % greater than normal, suppresses or retards white pulp differentiation and splenic vasculogenesis but enhances red pulp development. A single pars distalis gland placed as a chorioallantoic graft into operated embryos prevents the development of these defects except for liver growth which, while improved, is still subnormal. If the number of grafts is increased by one or two there is no change in the amount of influence on growth and development of the chick embryo. This apparent regulation occurs by some unknown mechanism even in the absence of the hypothalamus. Thus body and liver growth is normally stimulated by the pars distalis but spleen growth and red pulp differentiation are suppressed even though the gland stimulates splenic white pulp histogenesis. The hypothalamus, epiphysis and pars nervosa (removed by partial decapitation) are not apparently involved in the developmental endocrinology of the spleen in chick embryos.

Sign in / Sign up

Export Citation Format

Share Document