THE ADENOHYPOPHYSIS OF FEMALE RATS AFTER HYPOTHALAMIC OESTRADIOL IMPLANTS: AN ELECTRON MICROSCOPIC STUDY

1970 ◽  
Vol 47 (1) ◽  
pp. 101-110 ◽  
Author(s):  
D. ZAMBRANO ◽  
R. P. DEIS
Keyword(s):  
Microscopic Study ◽  
Adult Female ◽  
Median Eminence ◽  
Secretory Activity ◽  
Female Rats ◽  
Prolactin Cells ◽  
Electron Microscopic ◽  
Arcuate Nuclei ◽  
Periventricular Area ◽  
Ultrastructural Effect

SUMMARY The ultrastructural effect of oestradiol implants into the hypothalamus on the adenohypophysis of adult female rats was studied. The main results are the demonstration that mammotrophs or prolactin cells, and to a lesser extent somatotrophs, increased their secretory activity after bilateral implants into the median eminence and arcuate nuclei; in the periventricular area the reaction was weaker and in the anterior hypothalamus the response was negative. In animals with implants in the basal tuberal region, mammotrophs showed an asynchronous secretory activity. Mitosis has been found to occur in fully differentiated mammotrophs, a finding which can be correlated with the increased number of such cells after basal tuberal implants. The gonadotrophs appeared to be atrophied.

EFFECTS OF NEONATAL EXPOSURE TO MONOSODIUM GLUTAMATE ON THE ELECTRICAL ACTIVITY OF NEURONES IN THE MEDIOBASAL HYPOTHALAMUS, AND ON THE PLASMA CONCENTRATIONS OF THYROID-STIMULATING HORMONE AND PROLACTIN, FOLLOWING STIMULATION OF THE ROSTRAL HYPOTHALAMUS IN ADULT FEMALE RATS

1981 ◽  
Vol 89 (3) ◽  
pp. 379-387 ◽  
Author(s):  
D. J. SAPHIER ◽  
R. G. DYER
Keyword(s):  
Adult Female ◽  
Median Eminence ◽  
Monosodium Glutamate ◽  
Plasma Concentrations ◽  
Female Rats ◽  
Mediobasal Hypothalamus ◽  
Adult Rats ◽  
Thyrotrophin Releasing Hormone ◽  
Rostral Hypothalamus ◽  
Stimulation Of

Action potentials were recorded from 174 neurones in the mediobasal hypothalamus of ovariectomized adult female rats exposed neonatally to monosodium glutamate (MSG) and from 145 neurones in control rats. All of the animals, which were anaesthetized with urethane, had been ovariectomized for at least 3 weeks and received two injections of oestradiol benzoate (20 μg/100 g body weight, i.m.) 72 h and immediately before the recording experiments. The response of each neurone to electrical stimulation of the median eminence and rostral hypothalamus (preoptic and anterior hypothalamic areas; PO/AH) was analysed. The most striking feature of the results obtained was the significant (P < 0·001) loss of inhibitory responses in those neurones remaining in the adult rats after neonatal treatment with MSG. The loss of inhibitory responses applied to both stimulation sites. In each rat the response of one neurone, which was antidromically identified as projecting to the median eminence, was recorded before and during stimulation of the PO/AH at 50 Hz for 30 s in every min for 15 min. Before and after this stimulation blood was collected from a jugular vein for estimation by radioimmunoassay of concentrations of prolactin and TSH. In the MSG-treated rats significantly (P < 0·05) fewer neurones were inhibited by the 50 Hz stimulation than in control rats. In control rats the plasma concentrations of prolactin nearly quadrupled as an immediate consequence of this treatment, whereas in MSG-treated rats plasma concentrations barely doubled. However, in the MSG-treated rats plasma concentrations of prolactin continued to rise after stimulation ceased, possibly as a consequence of enhanced secretion of thyrotrophin releasing hormone.

scholarly journals Evidence for Terminal Regulation of GnRH Release by Excitatory Amino Acids in the Median Eminence in Female Rats: A Dual Immunoelectron Microscopic Study

Endocrinology ◽  
1998 ◽  
Vol 139 (3) ◽  
pp. 1458-1461 ◽  
Author(s):  
Shin-Ichi Kawakami ◽  
Kanjun Hirunagi ◽  
Masumi Ichikawa ◽  
Hiroko Tsukamura ◽  
Kei-Ichiro Maeda
Keyword(s):  
Amino Acids ◽  
Microscopic Study ◽  
Median Eminence ◽  
Excitatory Amino Acids ◽  
Female Rats ◽  
Gnrh Release

SEX DIFFERENCES IN CATECHOLAMINE CONTENT IN DISCRETE BRAIN NUCLEI OF THE RAT: EFFECTS OF NEONATAL CASTRATION OR TESTOSTERONE TREATMENT

1978 ◽  
Vol 89 (1) ◽  
pp. 20-28 ◽  
Author(s):  
W. R. Crowley ◽  
T. L. O'Donohue ◽  
D. M. Jacobowitz
Keyword(s):  
Sex Differences ◽  
Median Eminence ◽  
Arcuate Nucleus ◽  
Female Rats ◽  
Normal Adult ◽  
Adult Males ◽  
Brain Nuclei ◽  
Testosterone Treatment ◽  
Dopamine Concentration ◽  
Arcuate Nuclei

ABSTRACT Dopamine and norepinephrine levels were measured in individual brain nuclei in normal adult male and female rats and in adult male rats castrated on day 1 of life and in adult female rats given 1.25 mg testosterone propionate on day 4 of life. Normal adult males showed higher concentrations of dopamine than females in the caudate, tractus diagonalis and arcuate nuclei and in the median eminence. Day 1 castration of males reduced the dopamine levels of the arcuate nucleus and nucleus of the tractus diagonalis, while neonatal administration of testosterone to females elevated the dopamine concentration of the arcuate nucleus and nucleus of the tractus diagonalis. Normal adult males had higher concentrations of norepinephrine than females in the preoptic-suprachiasmatic, paraventricular, periventricular, and arcuate nuclei and in the median eminence. Neonatal endocrine manipulations (neonatal male castration and female testosterone treatment) failed to alter significantly these sex differences. The results suggest a sexual dimorphism in the catecholamine innervation of certain discrete areas of the brain and that the dopamine concentration in the arcuate and tractus diagonalis nuclei is influenced by perinatal androgen.

AN ELECTRON MICROSCOPIC STUDY OF NORMAL AND NEOPLASTIC ACIDOPHIL CELLS OF THE RAT PITUITARY

1971 ◽  
Vol 67 (1) ◽  
pp. 29-39 ◽  
Author(s):  
U. Schelin ◽  
P. M. Lundin
Keyword(s):  
Electron Microscopy ◽  
Secretory Granules ◽  
Female Rats ◽  
Male Rats ◽  
Cell Type ◽  
Prolactin Cells ◽  
Electron Microscopic ◽  
Gh Cells ◽  
Rat Pituitary ◽  
Close Relationship

ABSTRACT The morphology of normal and neoplastic acidophil cells of the rat pituitary has been studied by electron microscopy with special reference to the size and shape of the secretory granules. In the female rats, pregnant or non-pregnant, growth hormone (GH) cells and prolactin cells are easily separated, but in the male rats this separation is very uncertain. Acidophil tumours with granules similar to the GH type or to the prolactin type can be induced with stilboestrol treatment. These results indicate a close relationship between the two types of acidophil cells. They may be derived from a common progenitor which can be differentiated into either GH or prolactin cell or they may represent one cell type capable of producing both hormones.

scholarly journals ELECTRON MICROSCOPIC STUDIES OF THE ANTERIOR PITUITARY GLAND

1953 ◽  
Vol 1 (2) ◽  
pp. 93-113 ◽  
Author(s):  
JAMES F. RINEHART ◽  
MARILYN G. FARQUHAR
Keyword(s):  
Golgi Apparatus ◽  
Anterior Pituitary ◽  
Secretory Activity ◽  
Anterior Lobe ◽  
Female Rats ◽  
Great Promise ◽  
Ground Substance ◽  
Normal Female ◽  
Electron Microscopic ◽  
Thin Sections

Technical methods for preparation of thin sections suitable for electron microscopy, while exacting, have been developed to a point of useful application. A series of electron micrographs from such sections of the anterior lobe of the pituitary glands of normal female rats are presented. It is evident that in many respects the nuclear and cytoplasmic detail revealed surpasses that which can be achieved by light microscopy and offers great promise for research in problems of cytophysiology and pathology. The various cell forms as seen in the normal anterior pituitary are illustrated, and tentative interpretations of functional states are made. Cytologic structures clearly demonstrated include `specific' granules, mitochondria, Golgi apparatus, cytoplasmic ground substance and cell membranes. Some acidophiles contain delicate intracellular canaliculi (or lamellae), and cytoplasmic vesicles and vacuoles are prominent in certain basophiles. These alterations, which are associated with enlargement of the Golgi apparatus, are believed to reflect secretory activity.

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