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PubMed1990

Transsphenoidal hypophysectomy: a critical review.

The approach to resection of pituitary tumors has undergone radical changes over the past one hundred years and continues to change. Prolactinomas are the most common indication for hypophysectomy. While transsphenoidal hypophysectomy has now become the standard surgical procedure for gaining access to the pituitary fossa, alternative methods of approaching the sphenoid sinus are advocated. A thorough knowledge of sinonasal anatomy is essential for these transsphenoidal procedures, necessitating otolaryngologic consultation. While mortality is low with any of these procedures, the morbidity of the sublabial approach may be avoided with alternative techniques.

Contraindications↗
PubMed1989

Hypophysectomy differentially alters P-450 protein levels and enzyme activities in rat liver: pituitary control of hepatic NADPH cytochrome P-450 reductase.

Pituitary-determined hormones regulate the expression of hepatic cytochromes P-450 through processes involving both negative and positive controls. Accordingly, protein levels of several P-450 forms are elevated in rat liver following hypophysectomy [P-450 forms designated 2a (gene IIIA2), RLM2 (gene IIA2), and PB-4 (gene IIB1)], whereas protein levels of others are suppressed [e.g., P-450 2c (gene IIC11)]. In the present study, microsomal steroid hydroxylase activities associated with these same P-450 forms were found to be decreased by hypophysectomy, despite elevations in protein levels for several of them. Studies were, therefore, undertaken to determine the biochemical basis for this decrease in microsomal P-450 enzyme specific activity. In vivo treatment of hypophysectomized rats with gonadotropin, under conditions that restore heme to testis P-450, and heme reconstitution experiments carried out with liver homogenates indicated that a deficiency in P-450-associated heme is unlikely to account for the observed decreases in liver P-450 enzyme specific activity. Analysis of the flavoprotein P-450 reductase, however, revealed that the reductase protein and its associated cytochrome c reductase activity are decreased by 50 to 75% in liver microsomes isolated from hypophysectomized rats. Moreover, supplementation of isolated liver microsomes with exogenous purified P-450 reductase stimulated microsomal steroid hydroxylase activity preferentially in the hypophysectomized rats, to levels consistent with the observed changes in P-450 protein levels. Thus, a deficiency in P-450 reductase, which is a rate-limiting component for many P-450-dependent hydroxylation reactions, appears to be responsible for the decrease in steroid hydroxylase specific activity in the hypophysectomized rats. Although growth hormone, adrenocorticotropic hormone, and chorionic gonadotropin were each ineffective at restoring hepatic P-450 reductase when administered to hypophysectomized rats, substantial restoration of P-450 reductase levels could be achieved by treatment of the hypophysectomized rats with thyroxine. Thyroxine treatment of these rats also elevated the microsomal steroid hydroxylase activities associated with the individual hepatic P-450 forms to levels commensurate with their respective P-450 protein levels. These results establish that hepatic P-450 reductase is subject to hormonal controls that are distinct from those governing cytochrome P-450 expression and further demonstrate the complexity of endocrine control of hepatic steroid hormone metabolism.

Animals↗
PubMedDate not supplied

The pituitary mass after transsphenoidal hypophysectomy.

To understand the natural changes in the CT appearance of a pituitary mass after transsphenoidal hypophysectomy of a pituitary tumor, we obtained CT follow-up studies in 12 patients with pituitary adenoma. The heights of the pituitary masses on the coronal sections of each CT study were measured. It was found that the height of the pituitary mass did not return to normal immediately after the operation, despite complete removal of the pituitary tumor. Instead, the height gradually returned to normal between 3 and 4 months after the operation. Results of this study suggest that follow-up CT study of pituitary masses is best performed 3-4 months after transsphenoidal hypophysectomy.

Adenoma↗
PubMed1977

[Morphofunctional changes in the insular apparatus of the pancreas following hypophysectomy and administration of somatotropic hormone].

Mature white male rats were used to study effects of hypophysectomy and STH on sugar content after fasting and after reiterated glucose loading. Morphological and morphometrical investigation of the pancreatic endocrine tissue were made. Zinc content and distribution in the pancreas, as well as aldehydefuchsinophil granulation in B-cells of the islets of Langergans were studied. Hypophysectomy was stated to increase functional activity of the pancreatic insular apparatus. Injection of STH for 9 days resulted in the stimulation of the cells in the insular apparatus. Prolonged injection of STH (for 20 days) produced exhaustion of the pancreatic insular apparatus.

Animals↗
PubMed1979

Transsphenoidal hypophysectomy in the treatment of metastatic breast and prostate carcinoma.

The cases of 70 consecutive patients having a transsphenoidal hypophysectomy for metastatic carcinoma of the breast or prostate are reviewed. In half of the patients with cancer of the breast an objective remission was obtained. In 30 percent of the patients with cancer of the prostate there were objective signs of tumor regression and in 75 percent there was relief of pain. The operative mortality was 1.4 percent and the morbidity of the procedure was gratifyingly small. There is some indication that hypophysectomy may be preferred to adrenalectomy in patients with hormone-responsive metastatic mammary cancer.

Adult↗
PubMed1979

The effects of hypophysectomy on the retinomotor responses of the killifish, Fundulus heteroclitus.

This paper presents the results of an investigation concerned with the effects of long-term hypophysectomy on the retinomotor responses of the euryhaline killifish, Fundulus heteroclitus: 1. The eye of hypophysectomised Fundulus heteroclitus responds to light and dark in the same manner as that of intact controls: the retina is not in a state of permanent light-adaptation as claimed by Vilter (1942) for the hypophysectomised eel. 2. There is no evidence of a persistent circadian rhythm during continous darkness. 3. Unilateral illumination of the eye of intact fish results in dispersion of retinal pigment in both illuminated and unilluminated eyes, as in the goldfish (Ali, 1964), but no such contralateral response was evident after hypophysectomy. The cones are unresponsive.

Adaptation, Physiological↗
PubMed1975

[Transsphenoidal hypophysectomy in metastasizing breast cancers. Experience from 160 cases].

160 patients suffering from advanced metastatic cancer of the breast had transsphenoidal open surgical hypophysectomy. Mortality (1,8 p.cent) and morbidity were extremely low in view of the general conditions of the patients. Immediate relief of pain due to bone metastasis was obtained in 92 p.cent of cases. Such results emphasized the important point of achieving total hypophysectomy.

Adult↗
PubMed1980

[Hypophysectomy in the advanced stage of carcinoma of the prostate (author's transl)].

22 patients with advanced prostatic cancer underwent transnasal-transsphenoidal hypophysectomy. 2 patients died immediately after the operation, when this method was introduced. Of 19 patients, who were followed at short time intervalls, 13 = 68,5% showed a good remission, which lasted on an average of 5.5 (3-8) months. The survival time of these patients with a good remission was 11.5 months, whereas in patients without any remission it was 4.8 months. We recommend the hypophysectomy in individual cases as a possible form of treatment, which might lead to relief of pain and to objective tumor remission.

Humans↗
PubMed1980

Treatment of acromegaly by transethmoidal hypophysectomy.

The results of transethmoidal hypophysectomy are recorded in 34 patients with acromegaly. The post-operative growth hormone (GH) level was reduced to normal in 27 (80 per cent) and to less than 18 mu/l in 33 of the 34 cases. Two patients failed to respond clinically though in one of these the serum GH fell from 100 to 14 mu/l. Both the failures had had previous surgical interference. Amongst the responders there have been no recurrences. In view of these results we are of the opinion that transethmoidal hypophysectomy is at present the treatment of choice for acromegaly.

Acromegaly↗
PubMed1984

Effects of hypophysectomy and hormone replacement on the local and metastatic growth of Morris hepatoma 44.

We have demonstrated recently that the local metastatic growth of Morris hepatoma 44 is thyroid dependent ( Mishkin , S., Morris, H. P., Yalovsky , M., and Murthy , P. V. N. Gastroenterology, 77; 547-555, 1979; Mishkin , S. Y., Pollack , R., Morris, H. P., Yalovsky , M., and Mishkin , S. Cancer Res., 41: 3040-3045, 1981) and that exogenous thyroxine (8 micrograms/kg/day) and prolactin (100 micrograms/day) significantly stimulated tumor growth, while growth hormone (100 micrograms/day) failed to do so ( Pollack , R., Mishkin , S. Y., Morris, H. P., and Mishkin , S. Hepatology, 2: 836-842, 1982). In the present study, thyroid ablation (hypothyroidism) and hypophysectomy inhibited tumor growth significantly. These effects were almost totally reversed by administration of exogenous thyroxine to hypothyroid rats. While prolactin or growth hormone or thyroxine alone failed to restore tumor growth in hypophysectomized animals, administration of all three hormones partially but significantly reversed the inhibition of tumor growth. The number and size of pulmonary metastases paralleled local growth in all the above-mentioned conditions. Plasma membrane lactogenic receptors, measured using human growth hormone, were decreased in hypothyroidism and hypophysectomy groups. Binding levels were restored in those groups in which tumor growth was stimulated. In summary, the local and metastatic growth of Morris hepatoma 44 is affected by anterior pituitary hormones. Plasma membrane lactogenic receptors may mediate these effects.

Angiotensin II↗
PubMed1983

Hypophysectomy decreases retinal porphyropsin in the brook trout (Salvelinus fontinalis).

Hypophysectomy of brook trout (Salvelinus fontinalis) results in a decrease in retinal porphyropsin in animals maintained for one month under continuous light. After one month in continuous darkness, retinal porphyropsin decreases to zero percent in all hypophysectomized fish. The effect of hypophysectomy is reversed by treatment with 1 mg/liter of L-thyroxine in the aquarium water for one month. The results indicate that light-induced changes in visual pigment proportions are partly dependent upon factors regulated by the pituitary.

Animals↗
PubMed1982

[Influence of age, season and hypophysectomy on lipogenesis of adipocyte from rabbit. Insulin effects].

We studied lipogenesis, either from glucose or from acetate, spontaneous or stimulated by insulin, at the level of the isolated adipocyte of the rabbit's perirenal adipose tissue related to growth, season and hormonal troubles induced by hypophysectomy. 1. For the adipocyte, acetate instead of glucose is the major precursor for fatty acid synthesis. 2. Adipocyte lipogenesis of the immature rabbit of two months is higher than that which is observed in the mature rabbit of six months. 3. Adipocyte lipogenesis is strikingly more important in autumn than in spring, both in the young rabbit and the mature one. 4. After hypophysectomy, fatty acid synthesis from acetate is greatly increased at the level of the adipocyte and, in this case, insulin stimulates efficiently lipogenesis from acetate as well as from glucose.

Acetates↗
PubMed1978

Fine structure of Sertoli cells in the rat testis after hypophysectomy, testosterone treatment and re-involution.

Using thin sections and freeze-etch replicas the fine structure of the Sertoli cells of the rat testis was investigated after hypophysectomy, testosterone treatment and re-involution. 41 days after hypophysectomy the Sertoli cells contain numerous dense bodies and remnants of degenerating spermatocytes and spermatids. The Sertoli cell junctions are most prominent. The membranes of neighbouring cells are folded into several layers. Freeze-fracture replicas reveal a normal arrangement of Sertoli cell tight junctions with linear array of membrane particles preferentially on the B-face and complementary grooves on the A-face. The geometric pattern of the ridges is varying with respect to the basal, intermediate and apical portions of the lateral Sertoli cell membranes. Since no major changes of the size, distribution and localization of the Sertoli cell junctions were observed in the different experimental groups these junctions, once formed, are inferred to be independent from hypophyseal hormones.

Androgens↗
PubMedDate not supplied

Effect of pheochromocytoma and hypophysectomy on blood pressure and catecholamines in NEDH rats.

The New England Deaconess Hospital (NEDH) rat provides a valuable model with which to study pheochromocytoma (P); 59% of male rats 700 to 900 days old and 81% of those 900 days or older developed spontaneous P. One transplantable P (P259), when implanted into other NEDH rats, markedly increased plasma norepinephrine and dopamine as well as blood pressure, and usually caused death within 4 weeks. Even without P, about 83% of NEDH rats became hypertensive by 131/2 weeks of age and remained moderately hypertensive until 2 years of age when some animals developed spontaneous P and hypertension became severe. Whether a common mechanism is responsible for early appearance of hypertension and later development of P remains to be determined. Hypophysectomized NEDH rats remained normotensive or slightly hypotensive despite marked elevations of plasma norepinephrine and dopamine caused by P259 implantation; furthermore, survival was prolonged to 3 months. Catecholamine concentrations in plasma and RBC were usually quite similar, indicating that red blood cells play a significant role in inactivating circulating catecholamines. Unlike the normal adrenal, P259 in NEDH rats contains mainly norepinephrine and dopamine with little epinephrine; it appears that P259 is deficient in the enzyme phenylethanolamine-N-methyltransferase (PNMT), which converts norepinephrine to epinephrine. Why hypophysectomy prevents hypertension and prolongs life in rats with P259 implants is unclear; adrenal cortical and thyroid deficiency may play a role. Preliminary observations indicate that hypophysectomy can prevent spontaneous development of P in NEDH rats.

Adrenal Gland Neoplasms↗
PubMed1982

Hypothalamo-hypophysial neurosecretory system of the Indian mud-eel Amphipnous cuchia (Ham.) with a note on the regeneration of the pituitary stalk after hypophysectomy.

The nucleus preopticus (NPO) of Amphipnous cuchia is in the shape of an inverted-L-; the dorsal half of which constituted by the large neurons is the pars magnocellularis (PMC) and the ventral half formed of small cells is called pars parvocellularis (PPC). These cells are stained with aldehyde fuchsin, lead haematoxylin, chrome-alum-haematoxylin and alcian blue. The neurons of the NPO and nucleus lateralis tuberis (NLT) are positive to ascorbic acid test and axons could be traced into both anterior and posterior neurohypophysis. As the NLT neurons lie on the pathway of preoptico-neurohypophysial tract, they come in close contact with NPO axons. The axonal tract entering the pituitary ramifies into the adenohypophysis; more extensively in the pars intermedia where they have perivascular endings. Hypothalamo-hypophysial neurosecretory tract could be demonstrated with Golgi-Cox impregnation technique also. However, all the AF-positive axons do not seem to react positively to Golgi-Cox. In some cases, hypophysectomy is followed by the reorganisation of the proximal cut end of the stalk into a neurohypophysislike organ which is directed backwards. Occasionally some of the cut axons exhibited apparent uncontrolled growth. Hypophysectomy is accompanied by degeneration of some neurons in the PMC.

Animals↗
PubMed1981

Effect of hypophysectomy and castration on hepatic, pulmonary and intestinal aryl hydrocarbon hydroxylase activities in the rat.

The importance of the pituitary gland in the regulation of hepatic drug and steroid metabolism has been previously demonstrated. The present studies involving castrated and hypophysectomized-castrated male rats confirm that the pituitary gland is essential for the expression of the effects of testosterone and dihydrotestosterone on hepatic aryl hydrocarbon hydroxylase (AHH) activity and cytochrome P-450 content. Furthermore, the pituitary gland is required for the inhibitor effects of estradiol on hepatic AHH activity in castrated male rats. Neither castration nor hypophysectomy-castration alters AHH activity in lungs or intestine. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) administration to control animals increased AHH activity by 2-, 15-, and 66.5-fold in liver, lungs and intestinal microsomes, respectively. Hypophysectomy did not prevent TCDD from acting as an inducer of AHH in any of the tissues, although the AHH activities in the three tissues were approximately 60% lower in TCDD-treated, hypophysectomized animals as compared to TCDD-treated, sham-operated control animals treated with TCDD. The results indicate that the pituitary gland plays an important role in regulating the extent of AHH induction in liver, lung and intestine.

Animals↗
PubMed1979

Effect of hypophysectomy and growth hormone treatment on albumin mRNA levels in the rat liver.

A complementary DNA copy of purified rat albumin mRNA was employed in RNA-excess hybridization reactions to examine albumin mRNA levels in the liver of the hypophysectomized rat. In normal rat liver, albumin mRNA sequences were found to be about 10% of the total poly(A)-containing RNA population. Hypophysectomy reduced albumin mRNA levels by approximately 50%. Growth hormone treatment of hypophysectomized animals returned albumin mRNA to nearly normal levels. These effects on albumin mRNA sequences agreed closely with the changes in the synthesis of albumin that are assoicated with these conditions. The results suggest that hypophysectomy and growth hormone influence albumin synthesis by affecting the level of albumin mRNA.

Albumins↗
PubMed1995

[Effect of gonadotrophins, testosterone and growth hormone on spermatogenesis in two hypophysectomy patients].

Human chorionic gonadotrophin (hCG), human menopausal gonadotrophins (hMG) and somatotrope hormone (STH) were used for three months to induce spermatogenesis in a patient with azoospermia following hypophysectomy for Cushing's syndrome. Azoospermia reappeared when testosterone was substituted for hCG, despite continued treatment with FSH and STH. In a second patient who had undergone hypophysectomy for a craniopharyngioma presenting residual oligospermia, STH alone was uneffective in improving the sperm count. In both patients, the level of IGF-1 in seminal fluid was unchanged by STH despite increased serum IGF-1. The use of STH to induce spermatogenesis is discussed in light of its capacity to increase testosterone synthesis is response to hCG.

Adult↗