Browsing by Subject "Pituitary gland"
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- PublicationOpen AccessEosin-related fluorescence of acidophil pituitary cells(Murcia : F. Hernández, 1988) Friedman, H.; Friedman, I.V.C.; Mello, C.V.The examination of haematoxylin and eosin stained sections of normal and neoplastic pituitary glands under ultraviolet light illumination discloses fluorescence of acidophil cells. The distinction between prolactin and growth hormone-producing cells is not possible. Such fluorescence depends on previous eosin staining.
- PublicationOpen AccessGrowth hormone and prolactin immunoreactivity in the pituitary gland of postnatal little (lit) mice(Murcia : F. Hernández, 1986) Wilson, D.B.; Wyatt, D.P.Homozygous little (/it/lit) mutant mice exhibit a growth lag which is manifested at approximately two weeks postnatally. Functional aspects of the development of piruitary growth hormone (GH) cells and prolactin (PRL) cells were thus analyzed by means of colloidal gold immunocytochemistry at the ultrastructural level in lit/lit mice and their normal counterparts ranging in age from 5 days postnatally to adulthood. In the adult normal and lit/lit pituitaries, secretory granules in GH cells and PRL cells showed a positive immunoreaction to their respective antisera, as did granules in both cell-types at 5 days postnatally. By 14 days some GH cells in lit/lit pituitaries appeared to be less densely populated with granules than GH cells in normal pituitaries, but a positive immunoreaction continued to occur even in sparsely granulated GH cells. PRL cells showed ultrastructural features in lit/lit pituitaries which were similar to those in normal mice, and immunoreactivity was present at all stages examined. The results indicate that since differences in granule reactivity were not evident between lit/lit and normal GH cells, despite ultrastructural morphologic differences which were present by 14 days postnatally, manifestations of the defect in lit/lit may be primarily quantitative in terms of numbers of granules and/or numbers of GH cells. With respect to PRL cells, neither morphologic nor functional aberrations could be observed; thus, a deficit in PRL hormone production might be the result of a more subtle defect than that in GH cells.
- PublicationOpen AccessHypophyseal pathology in AIDS(Murcia : F. Hernández, 1992) Mosca, L.; Costanzi, G.; Antonacci, C.; Boldorini, R.; Carboni, N.; Cristina, S.; Liberani, C.; parravicini, C.; Pirolo, A.; Vago, L.One hundred and eleven pituitary glands of patients (93 males, 18 females; mean age 32 years, 5 months) who died of fully developed AIDS or ARC were examined under light microscopy with the aid of immunohistochemistry. On post mortem (p.m.) examination a wide series of multiorgan alterations was noticed. Microscopically vanous lesions in both adeno- and neurohypophysis were seen. These ranged from vessel damage to secondaries to systemic infections, neoplasms and functional derangements. Necrotic lumps due to recent infarction could appear in both parts of the gland, while old fibrous scars sustained a previously overcome necrosis. Different pathogens (mainly fungi) could be seen either within the gland or arising from its meningeal surroundings. Examples of tumour pathology were provided by microadenomas, gliosis/gliomas; the frequency of adenomas (11.7%) was similar to that typical of senility. The functional impairment was mainly connected with ACTH cell hyperplasia, which seems in keeping with corticoadrenal or ACTH-receptor damage.
- PublicationOpen AccessInfluence of luteinizing hormone-releasing hormone LHRH, treatment on cellular proliferation in the rat anterior pituitary(Murcia : F. Hernández, 1994) Carbajo, S.; Gonzalez, F.; López-Muñiz, A.; Carbajo-Pérez, E.This study was designed to gain insight into the action of LHRH on the control of cellular proliferation in the anterior pituitary. The fraction of cells labelled with bromodeoxyuridine (S-phase cells) was studied in cytospin preparations of anterior pituitary cells taken from control male and female rats and from rats treated with daily doses of 2 pg1100 g body weight of LHRH (7 days), with doses of 40 pg of LHRH given on alternate days for 14 days (7 doses) or, finally, treated with daily doses of 50 ng of busereline acetate (14 days). Treatment with LHRH for 14 days resulted in a significant increase in the fraction of S-phase cells. However, neither the blockade of gonadotrophin secretion with busereline acetate nor its stimulation with LHRH for seven days resulted in a significant change in the proliferative activity of anterior pituitary cells. This action was independent of sex. No significant changes were seen in the proportions of pituitary gonadotrops of the different study groups. Regardless of the treatmentgroup very few cells doubly-immunostained for BrdU and LH were found. It is concluded that LHRH may stimulate cellular proliferation in the anterior pituitary, but further studies are needed to define which cells are involved in this action.
- PublicationOpen AccessInsulin receptors and signal transduction proteins in the hypothalamo-hypophyseal system, a review on morphological...(Murcia : F. Hernández, 1998) Unger, J.W.; Betz, M.Receptors for insulin are widely distributed in the brain and pituitary. The current hypothesis on receptor function in these regions points to a role of insulin as a mediator in the communication of the peripheral endocrine system with the brain via various steps of the neuroendocrine axis. Recent data demonstrate that receptor-positive neurons in the brain, i.e. in the hypothalamus, and secretory cells in the anterior pituitary gland possess specific proteins that are thought to be involved in key steps of post receptor signal transduction, in particular insulin receptor substrate-1 and phosphatidylinositol 3'-kinase (PI3k). PI3k is a critical enzyme of the intracellular signaling pathway that is activated by a number of receptor tyrosine kinases, including receptors for insulin and IGF- 1. This information further completes the framework indicating in vivo activity of insulin receptors in central neuroendocrine cells and their involvement in one branch of several physiological mechanisms that control body metabolism and nutritional behaviour.
- PublicationOpen AccessInvolvement of pro-apoptotic and anti-apoptotic factors in the early development of the human pituitary gland(Murcia : F. Hernández, 2008) Saraga-Babic, Mirna; Bazina, Mirna; Vukojevic, Katarina; Bocina, Ivana; Stefanovic, VedranThe spatial and temporal pattern of appearance of pro-apoptotic caspase-3 and p53 proteins, and anti-apoptotic bcl-2 protein was investigated in the developing pituitary gland of 6 human embryos 5-8- weeks old, using morphological and immunohistochemical techniques. Their dynamic appearance was analyzed in the Rathke's pouch (future adenohypophysis), mesenchyme, and in the developing neurohypophysis. In the 5th and 6th week, caspase-3 positive cells appeared in the Rathke's pouch (5%) and stalk (11%), in the mesenchyme, but not in the neurohypophysis. In the 6th and 7th week, apoptotic cells were more numerous in the caudal part of the Rathke's pouch due to its separation from the oral epithelium. Pro-apoptotic p53 protein was detected in all parts of the pituitary gland throughout the investigated period. Nuclear condensations characterized cells positive to caspase-3 and p53 proteins. Apoptotic cells displayed condensations of nuclear chromatin on an ultrastructural level as well. While caspase-3 dependent pathway of cell death participated in morphogenesis of the adenohypophysis and associated connective tissue, p53-mediated apoptosis most likely participates in morphogenesis of all parts of the gland, including neurohypophysis. The anti-apoptotic bcl-2 protein was also detected in all parts of the developing gland. With advancing development, the positivity to bcl-2 protein increased in the cells of the adenohypophysis, while it decreased in the neurohypophysis. Bcl-2 protein probably prevented cell death in all parts of the gland and enhanced cell differentiation. The described pattern of appearance of the investigated pro-apoptotic and antiapoptotic factors might be important for normal morphogenesis and function of the pituitary gland.
- PublicationOpen AccessLocalization of androgen and estrogen receptors in rat and primate tissues(Murcia : F. Hernández, 2000) Pelletier, G.G. Pelletier
- PublicationOpen AccessMorphological restoration of gonadotrope population by thymulin gene therapy in nude mice(Murcia : F. Hernández, 2009) Reggiani, Paula; Martines, Eliana; Ferese, Celia; Goya, Rodolfo; Cónsole, GloriaThe integrity of the thymus during the first week of life is necessary for a proper maturation of the pituitary-gonadal axis as revealed by the significantly reduced levels of circulating gonadotropins in congenitally athymic (nude) mice. In the present work we studied the impact of athymia and the effect of neonatal thymulin gene therapy on the pituitaries of adult nude mice. Also circulating thymulin and gonadotropin levels were evaluated. We used an adenoviral vector expressing a synthetic gene for the thymic peptide thymulin (metFTS) termed RAd-FTS. On postnatal day 1, each experimental heterozygous (nu/+) and homozygous (nu/nu) pup of both sexes received a single bilateral i.m. injection of RAd-FTS or RAd-GFP/TK, a control vector expressing green fluorescent protein. On postnatal days 51-52, mice were bled and sacrificed, their pituitaries were immediately dissected, fixed and immunostained. Morphometry was performed by means of an image analysis system. The following parameters were calculated: volume density (VD: cell area/reference area), cell density (CD: number of cells/reference area), and cell size (expressed in μm2). Serum thymulin levels were measured by a bioassay and gonadotropin levels were assayed by RIA. It was observed that neonatal thymulin gene therapy in the athymic mice restored their serum thymulin levels and prevented the reduction in circulating gonadotropin levels. The histometrical analysis revealed that the treatment prevented the reduction in gonadotrope CD and the VD in athymic mice. Our data suggest that thymulin gene therapy may be an effective strategy to approach reproductive deficits associated with endocrine thymus dysfunction.
- PublicationOpen AccessNitric oxide in the stress axis(Murcia : F. Hernández, 1998) Lopez-Figueroa, M.O.; Day, H.E.W.; Akil, H.; Watson, S.J.In recent years nitric oxide (NO) has emerged as a unique biological messenger. NO is a highly diffusible gas, synthesized from L-arginine by the enzyme nitric oxide synthase (NOS). Three unique subtypes of NOS have been described, each with a specific distribution profile in the brain and periphery. NOS subtype I is present, among other areas, in the hippocampus, hypothalamus, pituitary and adrenal gland. Together these structures form the limbichypothalamic- pituitary-adrenal (LHPA) or stress axis, activation of which is one of the defining features of a stress response. Evidence suggests that NO may modulate the release of the stress hormones ACTH and corticosterone, and NOS activity and transcription is increased in the LHPA axis following various stressful stimuli. Furthermore, following activation of the stress axis, glucocorticoids are thought to down-regulate the transcription and activity of NOS via a feedback mechanism. Taken together, current data indicate a role for NO in the regulation of the LHPA axis, although at present this role is not well defined. It has been suggested that NO may act as a cellular communicator in plasticity and development, to facilitate the activation or the release of other neurotransmitters, to mediate immune responses, andlor as a vasodilator in the regulation of blood flow. In the following review we summarize some of the latest insights into the function of NO, with special attention to its relationship with the LHPA axis.
- PublicationOpen AccessPostnatal differentiation of the immunohistochemical expression of aromatase P450 in the rat pituitary gland(Murcia : F. Hernández, 2003) Carretero, J.; Vázquez, G.; Rubio, M.; Blanco, E.; Juanes, J.A.; Pérez, E.; Burks, D.; Vazquez, R.At our laboratory, we have recently demonstrated the immunohistochemical expression of aromatase P450 in the pituitary glands of adult rats; this expression was seen to be sex-dependent. In order to determine whether the changes in the expression of the enzyme are related to changes in the gonadal sphere and whether the expression of the enzyme is related to the postnatal differentiation of hypophyseal cytology, in the present work we performed an immunohistochemical study in the rat pituitary gland from birth to old age. The immunohistochemical reaction to aromatase was evident and very generalized at 7 days after birth, with no large differences between the male and female animals. At 14 days the immunohistochemical reaction was decreased in the females, with no changes in the males. At 17 days, aromatase immunoreactivity in the pituitary glands of female rats was very weak whereas the males showed large numbers of reactive cells. These observations were further pronounced at 21 days and 2 months of life. At 24 months, the immunoreactivity found in the pituitary glands of the male rats had almost completely disappeared. Our results show that a postnatal differentiation in the immunohistochemical expression of aromatase occurs; this is tightly linked to sexual activity and is lost in old age. This suggests that hypophyseal aromatase would be related to the mechanisms of action of gonadal steroids on hypophyseal differentiation and secretion.