Luteinizing hormone content of the pars tuberalis of the hypophysis of neonatally androgenized female rats

Summary The immunoreactive LH content of the pars tuberalis of neonatally androgenized female rats was studied and found to be significantly lower than that of control females at oestrus or of control males. It is concluded that the rat pars tuberalis does secrete LH and that this secretory activity is diminished by neonatal androgenization in a manner that differs from that reported for the LH secretion in the pars distalis.This investigation received financial support from Direccion de Investigacion, grants RMS-80-13 and S-80-26, Universidad Austral de Chile.     

Cytoimmunological study of the corticotrophic and corticomelanotrophic cells in the adenohypophysis of Boops salpa L. (marine teleost) in different experimental conditions (variation of salinity and of background color)]

The cytoimmunological study of the adenohypophysis of Boops salpa (marine Teleost), in different experimental conditions confirmed that the MacConaill's hematoxyline-positive cells contain: 1. ACTH (Corticotrophic Hormone) in the pars distalis, 2. MSH (Melanocyte-Stimulating Hormone) and ACTH in the pars intermedia.     

Immunocytological identification of two cell types in the intermediate lobe of the hypophysis of salmonids: presence of ACTH and alpha-MSH]

The lead-haematoxylin positive cells (PbH+) of the rostral pars distalis react with antibodies anti-1-24 ACTH and anti-17-39 ACTH; the pars intermedia (PI) is composed of two cell categories, but only one is revealed with cyto-immunological techniques and contains ACTH and alpha-MSH in several Salmonid species.     

Age-and sex-related development of ACTH in the pars distalis and neurointermedia of rat pituitary]

The content of ACTH of the pars distalis and neurointermedia of the pituitary of adult Rats is higher in the male than in the female. This differenciation of content, according to sex, appears at puberty at the site of pars distalis; it only appears around the 60th day of life at the site of the pars intermedia. The androgens seem to be responsible for the higher percentages observed in the males.     

Immunocytochemistry of pituitary corticotroph cells in terrestrial turtle (Testudo mauritanica)]

The immunocytochemical and histochemical characters of the corticotroph cells of the Turtle adenohypophysis have been studied. These cells are localised in the rostral part of the gland and are revealed by Is anti ACTH (1-24) and (17-39). They are also colored with lead hematoxyline and PAS-Orange G. The corticotroph nature of these cells is confirmed by the study of their modifications after treatment with amphenone and ACTH. The Is anti ACTH also reveal most of the cells of the pars intermedia; while the Is anti beta-MSH reveals only these cells and some scatter cells of the pars distalis.     

Effect of amputation and limb regeneration on the pars distalis of the newt,Notophthalmus viridescens

Summary A study of the pituitary of the newt,Notophthalmus viridescens, during limb regeneration indicated no observable changes in histology or ultrastructure of any of the cells of the pars distalis when compared with the pars distalis of unamputated control newts.This investigation supported by a grant from the National Research Council of Canada to S.R. Scadding.     

Sekretomotorische Fasern und Endigungen in der Adenohypophyse

Summary We demonstrated, in the pituitary of the animals examined, fibres which emerge from the Tr. hypothalamo-hypophyseal system and enter partly into the Pars intermedia and partlyvia the Pars tubularis into the Pars distalis and take their course directly towards the glandular cells. In the Pars distalis the nerve fibres end around the glandular cells in a special pericellular net.     

The adenohypophysial hormone content of the rat pars tuberalis.

The pars tuberalis of the hypophysis was shown to contain LH, which increases after castration, TSH and a very low amount of PRL. FSH was found after castration.     

Autoradiographic demonstration of estrogen uptake by the armadillo pituitary gland

Summary Adult female armadillos were injected with tritiated estradiol. The pituitary gland was removed and processed for autoradiography. Nuclear uptake and retention of the steroid was found in 28.8% of the cells in the pars distalis and 3.7% of the pituicytes.This study was supported in part by USPHS Research Career Development Award NS 00164 (PJS) and USPHS Grants NS 12933, HD 10914, HD 10202, and RR 07187.     

Natriuresis after water loading in rats bearing transplants of pars intermedia

Summary After water loading, rats bearing ocular grafts of the pars intermedia of the pituitary showed that the content of sodium increased in urine, whereas potassium excretion and diuresis did not vary significatively. These results suggest that in the rat the pars intermedia is involved in the regulation of the electrolyte metabolism.Professor and Chairman of Histology. Member of the Investigator Career of the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina.     

Estradiol-induced changes in TSH-like immunoreactivity of pituitary cells in female rats

Beta-thyrotropin (TSH)-producing cells in the pituitary pars distalis of female rats were studied using rabbit anti-rat beta-thyrotropin (TSH) serum and a peroxidase-antiperoxidase (PAP) immunohistochemical procedure. Animals were neonatally treated with 1 mg estradiol-dipropionate (EDP) and sacrificed at different stages of development up to adulthood. Intact females of the corresponding age served as the controls. Morphometry and stereology were used to evaluate the changes in TSH-cell number and volume densities of the cells and nuclei. All morphometric parameters examined in estradiol-treated animals showed a significant decrease in comparison with immunoreactive TSH cells of age-matched controls. The most prominent EDP-induced changes were evident in peripubertal 38-day-old rats, the number and volumetric densities of both TSH cells and their nuclei being reduced by about 90% compared to intact pituitary. This decrease in the number and volume densities of TSH cells in EDP-treated rats explicitly demonstrated that this hormone, applied neonatally, has an inhibitory effect on TSH-immunoreactive cells up to adulthood, in accordance with our earlier data obtained by light and electron microscopy.     

The adenohypophysial hormone content of the rat pars tuberalis

Summary The pars tuberalis of the hypophysis was shown to contain LH, which increases after castration, TSH and a very low amount of PRL. FSH was found after castration.This investigation was supported by the Fundación Instituto de Neurobiología and CONICET. The authors want to thank Dr A.F. Parlow for supplying the NIAMDD radioimmunoassay kits.     

Immunohistochemical detection of a substance resembling growth hormone-releasing factor in the brain of the rainbow trout (Salmo gairdneri)

We studied the distribution of an immunoreactive substance resembling growth hormone-releasing factor (GRF) in the hypothalamus and pituitary gland of the rainbow trout by immunofluorescence methods. The GRF-like immunoreactive perikaryon was observed in colchicine-treated fish. The majority of GRF-containing neurons were located in the nucleus lateral tuberis; others were located in the caudal part of the preoptic nucleus of the hypothalamus. The GRF-like immunoreactive neuronal processes projected into the pars distalis via the pars nervosa of the pituitary gland. The distribution of the GRF-like immunoreactive substance in the hypothalamus and pituitary gland suggests that GRF plays a physiological role in the regulation of growth hormone release from the pituitary gland of rainbow trout, as it does in mammals.     

Immunohistochemical detection of a substance resembling growth hormone-releasing factor in the brain of the rainbow trout (Salmo gairdneri)

Summary We studied the distribution of an immunoreactive substance resembling growth hormone-releasing factor (GRF) in the hypothalamus and pituitary gland of the rainbow trout by immunofluorescence methods. The GRF-like immunoreactive perikaryon was observed in colchicine-treated fish. The majority of GRF-containing neurons were located in the nucleus lateral tuberis; others were located in the caudal part of the preoptic nucleus of the hypothalamus. The GRF-like immunoreactive neuronal processes projected into the pars distalis via the pars nervosa of the pituitary gland. The distribution of the GRF-like immunoreactive substance in the hypothalamus and pituitary gland suggests that GRF plays a physiological role in the regulation of growth hormone release from the pituitary gland of rainbow trout, as it does in mammals.     

Hypothalamic and cerebral cortical inhibitors of a melanocyte-stimulating substance secreted by the pars distalis of the frog pituitary gland

Zusammenfassung Nachweis, dass die pars distalis der Hypophyse des LeopardfroschesRana pipiens eine Melanozyten stimulierende Substanz enthält, die in vitro abgesondert wird. Wässerige Extrakte aus Hypothalamus und Kortex des Frosches hemmen die Ausscheidung der die Melanozyten stimulierenden Substanz in vitro.     

Localization of a new neuroleptic in the pituitary gland of the rat

summary The¹⁴C-labelled, substituted benzamide neuroleptic Tiapride has been found to accumulate transiently in the pituitary gland of the rat following a single dose, and a prolonged retention of the drug was observed in the pars intermedia.     

Activation of the pituitary-adrenal axis by nipple suction in the lactating rat]

The response of the pituitary-adrenal axis to suckling in lactating Rats is dependent on two factors: 1. a psychic factor, which is identical by its effects to the psychological stress of the strange environment (transitory increase of plasma corticosterone and no significant modification of the content of ACTH in the two lobes of the pituitary); 2. a specific factor namely the stimulation of the nipples, which is distinguishable from the psychic factor by a longer release of corticosterone by the adrenals and a durable and significant decrease of the content of ACTH in the pars distalis.     

An immunofluorescent method for identification of isolated thyrotropic cells.

A sensitive and specific immunofluorescent method for identification of thyrotropic cells was developed. The TSH-producing cells were found to be heterogenic in their morphology and intensity of staining.     

Dopamine regulation of testicular activity in intact and hypophysectomized frogs,Rana esculenta

In intact frogs, both GnRHA and L-dopa were able to increase testicular and plasma androgen levels and to induce spermiation. The dopamine antagonist pimozide inhibited both the effects of L-dopa but not those of GnRHa. Hypophysectomy reduced androgen levels, but spermiation was still induced by both GnRHa and L-dopa, suggesting that these agents can directly influence the testis through a route not involving the pars distalis. Again, pimozide antagonised spermiation induced by L-dopa but not that induced by GnRHa.This work was supported (40% and 60%) by the Italian Ministry of Education and the C.N.R. Special Project.     

An immunofluorescent method for identification of isolated thyrotropic cells

Summary A sensitive and specific immunofluorescent method for identification of thyrotropic cells was developed. The TSH-producing cells were found to be heterogenic in their morphology and intensity of staining.