Showing papers on "Hypophysectomy published in 2003"
TL;DR: Sex hormones regulate the sex difference in hepatic PPARalpha levels, but not via the sexually dimorphic GH secretory pattern, which is not influenced by gender, gonadectomy, hypophysectomy, or GH treatment.
Abstract: Peroxisome proliferator-activated receptor (PPAR) α is a nuclear receptor that is mainly expressed in tissues with a high degree of fatty acid oxidation such as liver, heart, and skeletal muscle. Unsaturated fatty acids, their derivatives, and fibrates activate PPARα. Male rats are more responsive to fibrates than female rats. We therefore wanted to investigate if there is a sex difference in PPARα expression. Male rats had higher levels of hepatic PPARα mRNA and protein than female rats. Fasting increased hepatic PPARα mRNA levels to a similar degree in both sexes. Gonadectomy of male rats decreased PPARα mRNA expression to similar levels as in intact and gonadectomized female rats. Hypophysectomy increased hepatic PPARα mRNA and protein levels. The increase in PPARα mRNA after hypophysectomy was more pronounced in females than in males. GH treatment decreased PPARα mRNA and protein levels, but the sex-differentiated secretory pattern of GH does not determine the sex-differentiated expression of PPARα. T...
124 citations
TL;DR: It is concluded that a dynamic series of scans should be included in the CT protocol of the pituitary gland in dogs with PDH because it allows for identification of an adenoma or a diffusely abnormal pituitsary gland.
Abstract: Dynamic computed tomography (CT) of the pituitary gland was performed in 55 dogs with pituitary-dependent hyperadrenocorticism (PDH) that underwent transsphenoidal hypophysectomy. On routine contrast-enhanced CT images, microadenomas of the pituitary gland often are indistinguishable from nontumorous pituitary tissue because of isoattenuation. Dynamic CT may allow visualization of these adenomas. The changes in the contrast-enhancement pattern of the pituitary during dynamic CT in 55 dogs with PDH were correlated with surgical and histopathologic findings. In 36 dogs, dynamic CT identified distinct contrast enhancement of the neurohypophysis (pituitary flush). In 24 dogs, this pituitary flush was displaced, which indicated the presence of an adenoma. This observation was confirmed surgically and histopathologically in 18 of the 24 dogs. In 19 dogs, there was a diffusely abnormal contrast-enhancement pattern. CT findings agreed with surgical findings in 13 of these dogs and with histopathologic findings in all 19 dogs. It is concluded that a dynamic series of scans should be included in the CT protocol of the pituitary gland in dogs with PDH because it allows for identification of an adenoma or a diffusely abnormal pituitary gland.
50 citations
TL;DR: The findings suggest the importance of cystatin C and apolipoprotein E in the process of degeneration and/or regeneration of magnocellular neurons after hypophysectomy.
Abstract: To clarify the mechanism underlying the process of degeneration of injured CNS neurons, we have immunohistochemically examined the distribution of cystatin C, apolipoprotein E, IgG, transferrin and ferritin in the hypophysectomized rat hypothalamus. Stainings for ferritin revealed that reactive microglial cells massed in the paraventricular and supraoptic nuclei 14 days after hypophysectomy, when the degeneration of vasopressin neuronal cell bodies was apparent. Cystatin C-positive magnocellular neurons first appeared at 4 days and the number of intensely-stained cells increased rapidly up to the 7th day of hypophysectomy, followed by a decrease thereafter. Most of such cystatin C-positive neurons were simultaneously stained with anti-vasopressin serum. Accumulation of apolipoprotein E in extra-cellular spaces was obvious in the both hypothalamic magnocellular nuclei at 7 days. Several apolipoprotein E-positive cells were localized in the supraoptic nucleus, although the number of apolipoprotein E-positive cells was much smaller than that of cystatin C-positive cells. The experiments performed with the transferrin and IgG antibodies showed undetectable levels of such molecules in and around the degenerating magnocellular neurons during whole experimental periods. These findings suggest the importance of cystatin C and apolipoprotein E in the process of degeneration and/or regeneration of magnocellular neurons after hypophysectomy.
19 citations
TL;DR: It is postulated that FR by reducing the secretion of pituitary hormones, such as GH, diminishes the oxidativedamage of certain tissues, thereby delaying the development of age-related diseases inthese tissues and by this means extends life.
Abstract: Reducing the intake of food in rodents inhibits body growth, retards most physiological ageing processes, delays the onset of pathology and prolongs life. Food restriction (FR) reduces pituitary hormone secretion and in consequence has been called 'functional hypophysectomy'. Direct life-long comparisons in the rat showed that hypophysectomy (HYP) (a complete absence of pituitary hormones) has a greater anti-ageing action than FR (a partial lack of pituitary hormones) on collagen, kidney and muscle. This suggests that pituitary hormones accelerate ageing. Recent American research on genetic variants of the mouse indicates that pituitary growth hormone (GH) may accelerate ageing and shorten life. Both the Snell and Ames dwarf mice have a deficiency of pituitary GH and live 50% longer than normal mice. The Snell dwarf mouse has retarded ageing of both collagen and immune functions. The Ames dwarf mouse has high antioxidant enzyme activities in liver and kidney. A transgenic human GH mouse is short lived, has a low activity of antioxidant enzymes in liver and kidney and an early development of disease in these organs. It is postulated that FR by reducing the secretion of pituitary hormones, such as GH, diminishes the oxidative damage of certain tissues, thereby delaying the development of age-related diseases in these tissues and by this means extends life.
19 citations
TL;DR: Four dogs diagnosed as pituitary-dependent hyperadrenocorticism were treated with transsphenoidal hypophysectomy and postoperative hormone supplementation therapy and clinical signs such as alopecia and calcinosis cutis, as well as endocrinological abnormalities, were markedly alleviated after surgery.
Abstract: Four dogs diagnosed as pituitary-dependent hyperadrenocorticism were treated with transsphenoidal hypophysectomy and postoperative hormone supplementation therapy. On histological examination of the resected tissues, the tumors were ACTH-producing adenoma of the anterior lobe. Clinical signs such as alopecia and calcinosis cutis, as well as endocrinological abnormalities, were markedly alleviated after surgery. The clinical courses of these 4 dogs suggest that transsphenoidal hypophysectomy may be a useful treatment for pituitary-dependent hyperadrenocorticism.
18 citations
TL;DR: Investigation of the influence of growth hormone administration to hypophysectomized rats for 6 wk on accumulation of triglycerides in bone marrow and on the differentiation of primary marrow stromal cells into adipocytes under in vitro conditions found thatHypophysectomy significantly increased triglyceride concentration inBone marrow, which was attenuated by growth hormoneadministration.
Abstract: The hypophysectomized rat has been used as a model to study the effects of growth hormone deficiency on bone. Here, we have investigated the influence of growth hormone administration to hypophysectomized rats (HX) for 6 wk on accumulation of triglycerides in bone marrow and on the differentiation of primary marrow stromal cells into adipocytes under in vitro conditions. We found that hypophysectomy significantly increased triglyceride concentration in bone marrow, which was attenuated by growth hormone administration. Primary bone marrow stromal cells derived from HX rats also had more adipocytes at confluence compared with growth hormone-treated hypophysectomized (GH) rats. When stimulated with 3-isobutyl-1-methylxanthine plus dexamethasone (IBMX-Dex), preadipocyte colony counts increased more significantly in GH rats. Markers of adipocyte differentiation were higher in HX than in control or GH rats at confluence. However, after stimulation with IBMX-Dex, increased expression of markers was seen in GH compared with HX rats. In conclusion, growth hormone administration to hypophysectomized rats attenuated triglyceride accumulation in bone marrow and inhibited the differentiation of stromal cells into adipocytes in vitro.
14 citations
TL;DR: Administration of DDAVP effectively prevented hypernatremia that develops immediately after surgery and DI-like symptoms that persists for about one week after surgery.
Abstract: The prophylactic efficacy of desmopressin acetate (DDAVP) on diabetes insipidus (DI) after hypophysectomy was investigated in the dog. In the control group, hypernatremia with a plasma level of 155 mEq/l or higher persisted for 12 hr from the 4th to the 16th hour after hypophysectomy, and symptoms of DI developed within five days after surgery. In the DDAVP treatment group, these changes were not observed, showing that administration of DDAVP (4 microg, installation, twice daily) effectively prevented hypernatremia that develops immediately after surgery and DI-like symptoms that persists for about one week after surgery.
13 citations
TL;DR: Two methods of fetal pituitary removal provide consistent results as regards the weight increase of adrenal and thyroid glands, thymus gland and testicles, whereas the growth in length of the humerus bone was stimulated and retarded, respectively.
Abstract: A detailed description is given of a surgical technique for selectively removing the pituitary anlage from the intrauterine fetal rat as an alternative to the more generally applied fetal hypophysecto
3 citations
TL;DR: The clinical course of this case strongly suggested that hypophysectomy is a useful and effective treatment for canine PDH with macroadenoma when the disease was diagnosed in the early phase.
Abstract: An 11-year-old female West Highland white terrier weighing 8.3 kg was diagnosed as pituitary -dependent hyperadrenocorticism with pituitary macroadenoma. Surgical excision of the pituitary macroadenoma and hormone supplment therapy was performed. The tumor was histologically diagnosed as ACTH-producing adenoma. After the surgery, increased ALP and Tcho levels observed preoperatively reversed to the normal ranges, and the result of ACTH stimulation test was markedly improved. The systemic skin disorders observed preoperatively also remitted gradually and completely healed after three months of the surgery. The clinical course of this case strongly suggested that hypophysectomy is a useful and effective treatment for canine PDH with macroadenoma when the disease was diagnosed in the early phase.
1 citations
Journal Article•
1 citations