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PubMed1988

Distribution of 14 elements in various rat tissues following hypophysectomy, thyroparathyroidectomy, adrenalectomy, and castration.

The tissue distribution of 14 elements was simultaneously determined in rats 28 d after hypophysectomy (HPY), thyroparathyroidectomy (TPTY), adrenalectomy (ADY), and castration (CTN). The elements Na, K, Ca, Mg, Fe, S, P, Rb, Sr, Mn, Cu, and Zn were investigated in whole blood, plasma, brain, liver, kidney, heart, skeletal muscle, and bone. Additionally Mo was determined in kidney and liver. The following results were obtained: 1) With regard to hormone deficiency: HPY induced the most noticeable variations on all the elements tested owing probably to the direct and indirect effects of adenohypophyseal hormones. ADY led to the expected modification of Na and K but also to a Sr accumulation and a Rb depletion. TPTY induced a sharp decrease in plasma and tissues Ca, an increase in plasma P, but did not disturb the two elements in bone. An increase of Rb in many tissues and of Fe in heart, kidney, and liver were also observed. CTN had little consequences except in bone whose Cu and Fe contents were increased; 2) With regard to element variations: K, Mg, and S underwent little change. Discriminations were revealed between elements such as K and Rb, Ca and Sr, Ca and Mg, and Cu and Zn. The changes of Rb and Sr were consistent with regulatory mechanisms. The accumulation of Fe and Cu in tissues such as liver after HPY, TPTY, and ADY, suggest that the hormonal deficiencies could worsen the hemochromatosis and Wilson's disease; 3) With regard to plasma and tissues: No correlation appeared in element levels between plasma and other tissues. Brain was the least affected and liver, kidney and bone the most.

Adrenalectomy↗
PubMed1977

[Anesthetic studies on trans-sphenoidal hypophysectomy: retrospective study].

This paper deals with the retrospective analysis of anaesthetic management of 31 cases of trans-sphenoidal hypophysectomy. Good management relies on the following points: (1) a precise diagnosis supported by thorough hormonal investigation, (2) adequate pre- and per-op. administration of steroids, (3) adequate monitoring, (4) a fail-safe airway. The authors recommend the combined use of Innovar and halothane under light hypocapnea for the maintenance of anaesthesia. The routine use of deliberate hypotension is not indicated. Diabetes insipidus usually results from this operation and consequently must be treated.

Adolescent↗
PubMed2004

Immunocytochemical localization of mK1, a true tissue kallikrein, in the mouse parotid gland: sexual dimorphism and effects of castration and hypophysectomy.

In the normal parotid glands of mice at 12 weeks of age, mK1, a true tissue kallikrein, was detected at the apical rim of the striated ducts (SDs). Sexual dimorphism in the immunostaining intensity in parotid glands was seen, i.e., immunostaining was more intense in males than in females. Under electron microscopy, secretory granules, being small in size, and condensed at the subluminal cytoplasm, were labeled with immunogold particles showing the presence of mK1. These secretory granules were rather abundant and large in males. Castration in males reduced the immunoreactivity of mK1 in the SD cells because of a decrease in the number and size of secretory granules as revealed by electron microscopy. Hypophysectomy in male mice resulted in considerable loss of immunoreactivity for mK1, which was characterized under electron microscopy by complete disappearance or significant reduction of secretory granules in many SD cells. These results suggest that mK1 expression in the SD cells of murine parotid glands is regulated by pituitary-dependent hormones, and sexual dimorphism of mK1 expression is regulated by androgens.

Androgens↗
PubMed1988

Effects of hypophysectomy and administration of growth and thyroid hormones on the hydroperoxide-induced calcium release process and glutathione levels in rat liver mitochondria.

In order to investigate the effects of growth and thyroid hormones on Ca2+ transport in liver mitochondria, Ca2+ release and other accompanying changes induced by t-butylhydroperoxide were measured in mitochondria from hypophysectomized and hormone-injected rats. Mitochondria from normal and hypophysectomized rats showed similar rates of Ca2+ uptake (40 nmol.min.-1 mg protein-1) and ruthenium red-insensitive release (3 nmol.min.-1 mg protein-1). However, the t-butylhydroperoxide (0.5 mM)-induced release of 90% of the added Ca2+ required 1027 +/- 98 and 560 +/- 35 s in the hypophysectomized and normal groups, respectively, and the difference was independent of Ca2+. The release was accompanied by a loss of membrane potential, large amplitude swelling, the oxidation of NAD(P)H and stimulation of respiration. At conditions of equivalent release rates, the rate and extent of swelling as well as the stimulation of respiration were lower in mitochondria from hypophysectomized rats than those in the normal group. These results were confirmed by electron microscopy and provided evidence for a dissociation between the release of Ca2+ and the increase of membrane permeability. The administration of bovine growth hormone and/or 3,5,3'-triiodo-L-thyronine to hypophysectomized rats decreased the Ca2+ release times by different degrees and thyroid hormone was more effective than growth hormone. Hypophysectomy doubled the GSH content and hormone injections decreased it and the Ca2+ release times in parallel. Indeed, a high degree of correlation (r = 0.96) was obtained between mitochondrial GSH and the release times from groups of differing hormone status. Differences in the groups in the time required for oxidation of 80-90% of GSH were correlated with the differences in the times for release of 90% Ca2+. Therefore, these results demonstrated that growth and thyroid hormones can alter both the hydroperoxide-induced Ca2+ release and the metabolism of GSH in liver mitochondria, suggesting that the two processes are related. It is proposed that the effects of these hormones on Ca2+ transport may result from the promotion of its efflux from mitochondria and its mobilization into the cytosol.

Animals↗
PubMed1978

Effect of hypophysectomy on persistence of methylated purines in rat liver deoxyribonucleic acid after administration of dimethylnitrosamine.

The formation of methylated purines in DNA following dimethylnitrosamine administration was studied in control and hypophysectomized rats. When given the same dose of this carcinogen (in mg/kg body weight) the formation of the major product 7-methylguanine and of the minor products 1-, 3- and 7-methyladenine and 3-methylguanine was slightly greater in the livers of hypophysectomized rats than in controls. The rate of loss of these products from the DNA was not affected by hypophysectomy. O6-Methylguanine levels were significantly greater in the hepatic DNA of hypophysectomized rats compared to controls after doses of dimethylnitrosamine ranging from 1 to 20 mg/kg. This difference was due to a slower rate of loss of this purine from the DNA in the hypothysectomized rats. Growth hormone treatment increased the rate of removal of O6-methylguanine in the hypophysectomized rats but did not restore the activity to that found in controls. The possible significance of these results in the induction of tumors by dimethylnitrosamine is discussed.

Adenine↗
PubMed1985

Immunoreactive fibroblast growth factor (FGF) in rat tissues: molecular weight forms and the effects of hypophysectomy.

Rat tissues were extracted at neutral pH with dilute (0.15 M) ammonium sulfate and examined for presence of fibroblast growth factor immunoreactivity (ir-FGF). Ir-FGF was found in substantial amounts in all the tissues but higher amounts were found in liver and kidney. Gel filtration column chromatography showed the presence of three molecular weight peaks of ir-FGF, one associated with the void volume (the major form in kidney extract), another with an apparent molecular weight of 150-180,000 Da (the major form in serum) and a third one of 70,000 Da (the major form in the other tissues examined: pituitary, brain, liver, spleen and thymus). No immunoreactivity coeluted with authentic FGF purified from bovine pituitary glands, suggesting that FGF is present in neutral extracts in association with binding molecules and/or precursors. Hypophysectomy had no major effect on ir-FGF in the tissues, but increased its amount in serum. The results establish a wide distribution of FGF in several embryologically, morphologically and developmentally distinct tissues and indicate that the pituitary is not the major source of FGF immunoreactivity, although it can be involved in the regulation of plasma levels.

Animals↗
PubMed1986

Hypophysectomy may non-selectively alter pharmacokinetic parameters to enhance the ability of haloperidol to increase striatal dopamine receptor density in the rat.

We have investigated the effect of a range of doses of haloperidol (0.625-5.0 mg/kg/day) or saline, administered for 14 days, followed by a 3 day drug washout period, to sham operated or hypophysectomized rats. Haloperidol increased the number of specific striatal 3H-spiperone binding sites (Bmax) in sham-operated animals at doses of 2.5 and 5.0 mg/kg/day, and in hypophysectomized animals at all doses used (0.625-5.0 mg/kg/day). The inhibition of locomotor activity produced by haloperidol was greater in hypophysectomized than sham-operated animals. Plasma and striatal haloperidol levels after equivalent doses were greater in hypophysectomized than in sham-operated animals. We conclude that hypophysectomy may enhance the ability of haloperidol to induce striatal dopamine receptor supersensitivity in the rat, and that this may be due to differences in the pharmacokinetic handling of haloperidol between sham-operated and hypophysectomized animals.

Animals↗
PubMed1995

Effects of hypophysectomy and thyroxine on the expression of hepatic oestrogen, hydroxysteroid and phenol sulphotransferases.

Sulphation in rats, and other mammals, is carried out by a family of sulphotransferase isoenzymes, which can be further subdivided into oestrogen, hydroxysteroid and phenol sulphotransferases. We have examined the effects of hypophysectomy on the activity and expression of representative members of the three major sulphotransferase sub-families in male Wistar rat liver cytosols, and have found that the different sub-families are subject to differential regulation by pituitary hormones. Our data show that in male rat liver hydroxysteroid sulphotransferases activity was increased, oestrogen sulphotransferases activity was not altered and phenol sulphotransferases activity was reduced. Further, we have studied the effect on sulphotransferase expression of administration of thyroxine and dexamethasone to hypophysectomized rats. Treatment of hypophysectomized rats with thyroxine virtually abolished oestrogen sulphotransferase activity in male rat liver but had no effect on hydroxysteroid sulphotransferase or phenol sulphotransferase activity. Treatment of hypophysectomized rats with dexamethasone had no effect on sulphotransferase activities. Quantitative immunoblot analysis of liver cytosols showed that these changes in enzyme activity were related to changes in levels of the respective enzyme proteins.

Animals↗
PubMed1976

Ultrastructural changes in the vascular organ of the lamina terminalis following ovariectomy and hypophysectomy in the rat.

Based on quantitative evaluations it was observed that 4 and 14 days after ovariectomy, as well as 2 months after hypophysectomy, the larger granulated vesicles (70-110 nm in diameter) in the nerve terminals of the vascular organ of the lamina terminalis (OVLT) almost disappeared. The findings are consistent with the view that the OVLT may play a role in the control of pituitary gonadotrophic function.

Animals↗
PubMed1981

Effect of hypophysectomy and pituitary stalk transection on alpha-melanocyte-stimulating hormone-like immunoreactivity in the brain of the frog, Rana ridibunda Pallas.

The existence of an alpha-MSH-like molecule in the frog brain led us to investigate the role of the pituitary gland in the maintenance of the alpha-MSH content in 3 different regions of the brain. Acetic acid extracts of hypothalamus, rhombencephalon and telencephalon were analyzed by means of a highly specific radioimmunoassay for alpha-MSH in normal, sham-operated, pituitary disconnected and hypophysectomized frogs. Transection of the pituitary stalk gave rise to a significant decrease in alpha-MSH content in the intermediate lobe of the pituitary gland (-71% after 3 days), but did not affect alpha-MSH content in the distal lobe or in the brain. Eight days after total hypophysectomy, an alpha-MSH immunoreactive compound, co-eluting with synthetic alpha-MSH on Sephadex G-25, was found in the 3 brain regions studied. Removal of the whole pituitary gland did not significantly modify alpha-MSH content in the hypothalamus and the telencephalon. A slight increase in alpha-MSH was even observed in the rhombencephalon of hypophysectomized animals. Furthermore, no modification in alpha-MSH immunoreactivity occurred in any region of hypophysectomized animals. These results demonstrate the existence of alpha-MSH-like material in the brain of Rana ridibunda and establish that brain alpha-MSH in the frog is not of pituitary origin.

Animals↗
PubMed1984

Quantitative immunocytochemistry of corticotropin-releasing factor (CRF). Studies on nonbiological models and on hypothalamic tissues of rats after hypophysectomy, adrenalectomy and dexamethasone treatment.

Indirect immunofluorescence cytochemistry of ovine corticotropin releasing factor (oCRF) was performed by use of an antiserum raised against a conjugate of oCRF and bovine thyroglobulin. The staining intensity was quantitated by use of an automated microfluorimeter. In cryostat sections of formaldehyde fixed oCRF containing gelatine models, the staining intensity was dependent on the concentration of oCRF (1-100 microM) added to the gel. Immunoinhibition experiments showed that oCRF induced identical concentration-dependent (0.001-1 microM) quenching of the immunostaining of oCRF containing models and rat median eminence (ME) preparations. Comparison of immunoinhibition of oCRF and ME extracts indicates that approximately 1.5 ng of CRF immunoreactivity (CRFi) is present in the ME of intact adult male Wistar rats. In the hypothalamus of rats, the majority of CRFi nerve fibers are localized in the external zone of the median eminence, whereas a large population of CRFi cell bodies is present in the paraventricular nucleus. Manipulations of the pituitary-adrenal system result in changes in the distribution of CRFi in these neurons. One week after extirpation of the adrenals or of the pituitary gland, the CRFi in the ME was reduced to 32 +/- 3% and 48 +/- 6% respectively. This decrease in CRFi in the median eminence can be largely prevented by treatment of rats with dexamethasone in doses that effectively reduce plasma ACTH and corticosterone levels. In contrast to intact rats, CRFi cell bodies can be visualized in the paraventricular nucleus of non-colchicine-treated rats after adrenalectomy or hypophysectomy. These data support the view that the hypothalamic CRFi neurons play a central role in the control of pituitary-adrenal activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenalectomy↗
PubMed1987

Effects of adrenalectomy and hypophysectomy on postictal seizure protection.

Endogenous opioid systems activated by seizures appear to contribute to the postictal inhibition of subsequent seizure activity. In consideration of the possible postictal anticonvulsant actions of endogenous opioids of peripheral origin, we examined whether intact adrenal or pituitary sources of these opioids are necessary for the progressive decline in convulsion intensity and duration normally recorded during a series of 6 intermittent maximal electroshocks (MES). Adrenalectomy did not alter the progressive seizure protection associated with repeated MES. Hypophysectomy, in contrast, increased convulsion duration and abolished progressive reductions in convulsion severity. These data indicate that: adrenal secretions do not substantially contribute to postictal protective mechanisms, and endogenous opioids of pituitary origin may be involved in postictal protective mechanisms.

Adrenal Glands↗
PubMed1994

Upregulation of nitric oxide synthase and galanin message-associated peptide in hypothalamic magnocellular neurons after hypophysectomy. Immunohistochemical and in situ hybridization studies.

The expression of several bioactive molecules in magnocellular hypothalamic neurons is modified when the axons of these cells are transected. In this study we have evaluated by means of immunocytochemistry and in situ hybridization the effect of hypophysectomy on the expression of nitric oxide synthase (NOS)- and of galanin message-associated peptide (GMAP)-like immunoreactivities (-LIs) as well as on their respective mRNAs in hypothalamic magnocellular neurosecretory neurons. The results show a transient increase in NOS- and GMAP-LIs in magnocellular neurons of both the paraventricular and supraoptic nuclei when compared to normal animals. The maximal increase in staining was observed between 5 and 7 days, and by 14 days NOS-LI was back to normal levels, whereas strong GMAP-LI could still be detected in a few cells. A similar picture was observed for the NOS and GMAP mRNAs. The functional significance of the present findings is unclear, but they indicate a possible role of nitric oxide and GMAP in neurosecretory neurons after injury.

Amino Acid Oxidoreductases↗
PubMed1984

Effects of hypophysectomy and prolactin on calcium regulation in the red-spotted newt, Notophthalmus viridescens.

Hypophysectomized male red-spotted newts exhibited hyponatremia but not hypocalcemia. Parathyroidectomy and a combination of hypophysectomy and parathyroidectomy caused plasma calcium levels to fall, but control levels were reestablished within 12 days. Injections of ovine prolactin had no effect on the plasma calcium or sodium levels of sham-operated and parathyroidectomized newts conditioned in tap water or in a 0.6% sodium chloride solution containing 10 meq calcium/liter. These data indicate that the pituitary gland is not involved in the hypercalcemic regulation of the red-spotted newt.

Animals↗
PubMed1985

A method for hypophysectomy of the sexually mature sterlet, Acipenser ruthenus L., and the state of the fish after the operation.

Hypophysectomy was performed on sexually mature sterlets, Acipenser ruthenus L., in summer and autumn. The operation usually lasted about 45 sec, but never longer than 90 sec. After the parasphenoid was stripped, an ellipsoid hole was trepanated at the level of the eyes. The hypophysis was ablated by catching its rostral end with a pincer. As the result of the extirpation of the hypophysis the majority of the specimens grew steadily lighter, and a considerable loss of the body weight as well as macroscopical changes in the internal organs were observed. The survival rate after the operation was 100% among the fish operated on in autumn and 74-81% of those operated on in summer. Histological examination verified completeness of the extirpation of the gland. The saccus vasculosus was ablated partially or fully together with the hypophysis and the bottom of the infundibulum of the diencephalon was injured in 20-25% of the animals. However, the preoptic nucleus and the proximal part of the preoptic-hypophysial tract were not damaged.

Animals↗
PubMed1988

Effects of salinity, hypophysectomy, and prolactin on whole-animal transepithelial potential in the tilapia Oreochromis mossambicus.

We have examined whether two recently isolated forms of tilapia (Oreochromis mossambicus) prolactin exert similar effects on osmoregulatory physiology. The effects of salinity, hypophysectomy, and replacement therapy with tilapia prolactins on whole-animal transepithelial potential (TEP), gill Na+, K+-ATPase activity, and plasma ions were determined. When intact fish adapted to 25% seawater (SW) were transferred to different salinities, TEP reached a steady state after 10 hr; TEP increased with increasing salinity from fresh water (FW) to 75% SW but was stable from 75 to 125% SW. Plasma osmolality, [Na+], and [Cl-] of these fish 24 hr after salinity change showed that fish in 100 and 125% SW had greater osmotic perturbation than those transferred to lower salinities. Following a 5-day recovery period in 25% SW, hypophysectomized fish transferred to FW for 10 hr had significantly lower TEP and plasma ion levels than either sham-operated fish or intact fish under the same conditions. Injection of hypophysectomized fish with "small" prolactin (tPRL177), "large" prolactin (tPRL188), or a combination of both (0.5 micrograms/g body weight) 22 hr and again 20 min prior to transfer from 25% SW to FW, restored TEP and plasma ion levels to those of sham-operated fish. Neither prolactin affected the TEP or plasma ions of sham-operated (intact) fish. Hypophysectomized fish had lower gill Na+,K+-ATPase activity than sham-operated fish in FW, but prolactin injections as described above did not affect gill Na+,K+-ATPase activity in either hypophysectomized or sham-operated fish. Our results indicate that the two forms of prolactin are indistinguishable with regard to several aspects of tilapia osmoregulation.

Animals↗
PubMed1992

Influence of hypophysectomy, castration, fasting, and spermiation on SBP concentration in male rainbow trout (Oncorhynchus mykiss).

The influence of different experimental and physiological conditions on sex steroid binding protein (SBP) concentrations in the blood (and in hepatic and testicular cytosols) has been studied on male rainbow trout. SBP was measured with a specific binding assay. The aim was to further understanding of regulation of the SBP and in particular to determine the respective influences of reproductive and metabolic status. Twelve days after hypophysectomy, pituitary and steroid hormones were dramatically decreased and SBP concentrations were significantly lowered in blood (-32%) and in hepatic cytosol (-46%) while the binding protein concentration remained constant in testicular cytosol. Castration of maturing animals did not influence SBP concentration in blood and liver cytosol. Toward the end of the reproductive cycle, a dramatic decrease (-80%) of plasma SBP concentration occurred that appears independent of androgen changes that take place during this period, but is concomitant with a rapid increase of plasma growth hormone (GH) levels (and possibly secondary to a natural arrest of food intake). Long-term fasting that increases endogenous GH but decreases plasma IGFs (insulin-like growth factors) concentrations also induces a limited but significant decrease in SBP concentration. Treatment of intact control trout with recombinant bovine GH (1 microgram/g wt, twice a week, for 6 weeks) increased plasma IGF concentrations but did not significantly increase SBP levels. These results suggest that in mature male trout, testicular androgens have little or no influence on SBP regulation. GH levels or liver GH responsiveness and IGF might be involved in SBP regulation. This would, in part, explain the large decrease in SBP around spermiation in trout.

Animals↗