ADRENOCORTICOTROPHIC HORMONE IN THE ANTERIOR AND NEUROINTERMEDIATE LOBES OF THE FETAL RAT PITUITARY GLAND

1981 ◽  
Vol 89 (2) ◽  
pp. 181-186 ◽  
Author(s):  
ALAIN CHATELAIN ◽  
J. P. DUPOUY
Keyword(s):  
Pituitary Gland ◽  
Functional Differentiation ◽  
Pars Intermedia ◽  
Adrenocorticotrophic Hormone ◽  
Pars Distalis ◽  
Adult Rats ◽  
Adrenal Cells ◽  
Specific Radioimmunoassay ◽  
Fetal Rat ◽  
Rat Pituitary

The concentration of ACTH in the pars distalis and pars intermedia of the fetal rat hypophysis from days 17–21 of pregnancy was measured with a specific radioimmunoassay and a bioassay using isolated adrenal cells from adult rats. In both lobes of the pituitary gland, a significant correlation was observed between immunoreactive and bioreactive values, expressed as pg equivalents synthetic human 1–39 ACTH per μg protein. In the pars distalis, ACTH concentrations increased steadily from days 17–20 and then remained unchanged to term. At this time they were tenfold higher than on day 17. In the neurointermediate lobe, ACTH was detected only from day 18; the concentration of ACTH increasing between days 18 and 19. At each of the stages of pregnancy examined, the concentration of ACTH in the pars distalis was greater than that in the pars intermedia. These data have demonstrated that ACTH is present in both anterior and neurointermediate lobes of the fetal rat hypophysis, that the functional differentiation of the pars distalis takes place earlier than that of the pars intermedia, and that the concentrations of corticotrophin in the pars distalis and in the pars intermedia have different patterns of development as gestation progresses.

PERFUSION OF INTERCELLULAR SPACES IN THE PARS DISTALIS AND THEIR VARIATION WITH TIME OF DAY

1975 ◽  
Vol 66 (3) ◽  
pp. 385-NP
Author(s):  
W. B. QUAY
Keyword(s):  
Pituitary Gland ◽  
Functional Significance ◽  
Time Of Day ◽  
Male Rats ◽  
Pars Distalis ◽  
Intercellular Spaces ◽  
India Ink ◽  
Structural Regularity ◽  
Rat Pituitary ◽  
Light Darkness

SUMMARY Microperfusion of the tissue parenchyma of regions of the rat pituitary gland with 1:1 dilutions of India ink revealed a network of fine intercellular spaces or canaliculi throughout the pars distalis. They were demonstrable in animals of all ages from 1·5 months to over 1 year, in both sexes, and at various times during the 24 h light–darkness cycle. However, 24 h rhythms were suggested in the radial perfusion distance (P < 0·05) and tissue density (P < 0·01) of the perfused canaliculi in adult male rats. The amplitude of the 24 h rhythmicity in these pituitary canaliculi was lower than that shown recently in pineal canaliculi of the same species. Structural regularity and evidence of rhythmic and physiologically correlated changes in the pituitary canaliculi suggest that they relate to natural features rather than being only artifactual, and that analysis of their possible functional significance is appropriate.

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).

RESPONSES OF THE PARS INTERMEDIA OF THE CAT'S HYPOPHYSIS TO ADRENOCORTICOTROPHIC HORMONE

1954 ◽  
Vol 10 (2) ◽  
pp. 124-NP ◽  
Author(s):  
J. N. KARKUN ◽  
AMIYA B. KAR ◽  
B. MUKERJI
Keyword(s):  
Physiological State ◽  
Pars Intermedia ◽  
Adrenocorticotrophic Hormone ◽  
Pars Distalis ◽  
Intramuscular Injections ◽  
Cytological Changes

SUMMARY Prolonged intramuscular injections of adrenocorticotrophic hormone (ACTH) into kittens cause marked hypertrophy of the basophil cells of the pars intermedia and cytological changes resembling the hyaline changes described in the same cells of the pars distalis. These changes indicate an altered physiological state of the basophils and probably an enhanced output of intermedin. The lack of response of the basophil cells of the pars distalis or of other cells of the pars intermedia suggests that the basophils of the two hypophysial components are physiologically dissimilar, and those of the pars intermedia are solely responsible for the elaboration of intermedin.

Immunohistological study of the anterior pituitary gland ? pars distalis and pars intermedia ? in dwarf mice

1982 ◽  
Vol 223 (2) ◽  
pp. 415-420 ◽  
Author(s):  
Michelle Roux ◽  
Andrzej Bartke ◽  
Francis Dumont ◽  
Maurice P. Dubois
Keyword(s):  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Anterior Pituitary Gland ◽  
Pars Intermedia ◽  
Pars Distalis ◽  
Dwarf Mice ◽  
Immunohistological Study

Proliferation and differentiation of thyrotrophs in the pars distalis of the rat pituitary gland during the fetal and postnatal period

2001 ◽  
Vol 203 (4) ◽  
pp. 249-253 ◽  
Author(s):  
Y. Taniguchi ◽  
Satoru Yasutaka ◽  
Rieko Kominami ◽  
Harumichi Shinohara
Keyword(s):  
Pituitary Gland ◽  
Postnatal Period ◽  
Pars Distalis ◽  
Rat Pituitary ◽  
Proliferation And Differentiation
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