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PubMed1981

Intracranial traumatic aneurysm following hypophysectomy.

A case of traumatic aneurysm of the ICa following an attempted hypophysectomy is reported, and the management of the case is discussed. Extensive review of the English literature and personal communications (Angell-James, Bateman, Symon, Richards) have revealed only four other proven cases of intracranial aneurysms following operations on the ear and nose, one each following nasal polypectomy and partial intra-nasal ethmoidectomy, trans-antral ethmoidectomy, hypophysectomy, and mastoidectomy.

Carotid Artery Injuries↗

PubMed1978

The time course of the effect of hypophysectomy and oestrogen treatment on the hepatic metabolism of androst-4-ene-3,17-dione in male and female rats.

Hypophysectomy of male animals has little effect on the hepatic androst-4-ene,3,17-dione (androstenedione) metabolism, except for possible changes in the kinetics of the 16alpha-and 7alpha-hydroxylases. On the other hand, hypophysectomy of female animals leads to a "masculinization" of hepatic androstenedione metabolism, following the changes seen in Vmax. of the enzymes involved, probably due to the removal of the source of "feminizing factor" thought to maintain the "female" type of metabolism in the liver. There seems to be a temporal dissociation of the effects on the various enzymes, indicating different cellular control mechanisms for these enzymes. Oestrogen treatment of male rats causes "feminization" of the hepatic androstenedione metabolism. The time study shows an initial increase in 17-hydroxy steroid oxidoreductase and 6beta- and 16alpha-hydroxylase activities, followed by a decrease to the values in females. This biphasic effect is possibly due to an initial direct effect via the hypothalamo-pituitary system.

Androstenedione↗

PubMed1979

Corticotropin regulation of the synthesis of a specific rat adrenal cytosolic protein. Effects of hypophysectomy and actinomycin D.

The mechanism of corticotropin stimulation of the synthesis of a specific rat adrenal cytosolic protein was investigated. This protein (protein E) has a mol.wt. of approx. 30000. It is detected by polyacrylamide-gel electrophoresis of cytosol prepared from adrenal slices from rats treated with corticotropin in vivo and control rats, the slices being incubated with [(3)H]- and [(14)C]-leucine respectively. In rats 1-15 days after hypophysectomy, corticotropin, like dibutyryl cyclic AMP, induces an increase in protein E similar to that induced in control rats, even though both compounds no longer stimulate total protein synthesis. Corticotropin stimulation of protein E synthesis is mediated by cyclic AMP but not by corticosterone, since aminoglutethimide, a steroidogenic inhibitor, does not affect corticotropin stimulation, and dexamethasone alone has no effect. Actinomycin D, when injected in vivo 1h before or after corticotropin injection, prevents the effect of corticotropin on protein E synthesis, which is interpreted as evidence that mRNA synthesis is necessary for the stimulation of protein E synthesis. When injected more than 2h after corticotropin, actinomycin D does not prevent corticotropin stimulation of protein E synthesis, but completely blocks corticotropin stimulation of total protein synthesis. This is interpreted as meaning that, after stimulation of mRNA coding for protein E, corticotropin has no effect on the synthesis of protein E. On the other hand, corticotropin stimulation of protein E synthesis persists after hypophysectomy even though it no longer stimulates total protein synthesis. These data suggest that the factor(s) involved in the synthesis of protein E are more stable than those involved in total protein synthesis.

Adrenal Glands↗

PubMed1988

Regulation of phenobarbital-inducible cytochrome P-450s in rat and mouse liver following dexamethasone administration and hypophysectomy.

Cytochrome P-450s are a superfamily of haem-containing proteins involved in the metabolism of foreign compounds, as well as a variety of endogenous molecules. The hepatic levels and function of this diverse group of enzymes are determined by both constitutive and xenobiotic regulators. To examine the role of constitutive factors in cytochrome P-450 regulation, the levels of three distinct groups of phenobarbital-inducible hepatic cytochrome P-450s were studied following dexamethasone-treatment or hypophysectomy. In the mouse, dexamethasone was a potent inducer of proteins within the PB1 (subfamily IIC), PB2c (family III) and PB3 (subfamily IIB) families. These findings were strikingly different from the effects in the rat where essentially no effect on PB3 expression and indeed suppression of proteins related to PB1 was observed. Determination of mRNA concentration indicated that the difference was at the level of transcription. These findings indicate that synthetic glucocorticoids have the potential to be potent phenobarbital-like inducing agents. In the mouse hypophysectomy, like dexamethasone, induced hepatic mRNA of P-450 from families P-450IIB, P-450IIC and P-450III. Again a species difference was observed as this treatment had essentially no effect in the rat. These data in the mouse indicate that factors produced in the pituitary can either affect the transcription rate of phenobarbital and dexamethasone-inducible P-450 genes or influence the stability of their mRNAs.

Animals↗

PubMed1989

Hypophysectomy does not alter the acinar zonation of gluconeogenesis or the mitochondrial redox state in rat liver.

The biochemical and functional heterogeneity of hepatocytes in different zones of the liver acinus may be related to the concentrations of hormones within the liver acinus. We examined the effects of hypophysectomy, which causes marked changes in plasma hormone levels and in activities of hepatic enzymes that are normally heterogeneously distributed, on the degree of metabolic zonation within the liver acinus. In hypophysectomized rats the activity of alanine aminotransferase was increased, but its normal zonation (predominance in the periportal zone) was preserved. The activity in cultured periportal and perivenous hepatocytes was increased by dexamethasone, but not by glucagon. Periportal hepatocytes from hypophysectomized rats expressed higher rates of gluconeogenesis in culture than did perivenous hepatocytes, irrespective of the absence or presence of dexamethasone, glucagon or insulin. Similar differences in rates of ketogenesis and in the mitochondrial redox state in response to glucagon were observed between periportal and perivenous hepatocytes from hypophysectomized rats as between cell populations from normal rats. Although hypophysectomy causes marked changes in hepatic enzyme activities, it does not alter the degree of zonation of alanine aminotransferase, gluconeogenesis or the mitochondrial redox state within the liver acinus.

Alanine Transaminase↗

PubMed1997

Effect of hypophysectomy on endocrine cell types in rat gastrointestinal mucosa.

The effect of hypophysectomy on the gastrointestinal tract was studied in the rat 8 wk after operation, particularly regarding the frequency and distribution of serotonin, somatostatin and gastrin-immunoreactive cells. Body weight, the length of the intestine and the thickness of the mucosa of the antrum and small intestine were all reduced in the hypophysectomised rats compared with sham-operated and untreated controls. In the hypophysectomised animals the serotonin-immunoreactive cells were fewer in the antrum and caecum, whereas they were more numerous in the proximal large intestine. There were fewer gastrin-immunoreactive cells in the antrum, while the somatostatin-immunoreactive cells were more numerous in the antrum and caecum. The significant influence of hypophysectomy on the gastrointestinal tract could be direct, but could also be associated with the marked effect of pituitary deficiency on endocrine cells, known to exert both trophic and antitrophic actions. However, it could also be an indirect effect on metabolism, resulting in lower food intake, other endocrine cell systems, and growth factors.

Animals↗

PubMed1980

Somatomedin-A bioactivity in rabbit serum after hypophysectomy.

Hall's bioassay was used to determine the somatomedin (Sm) activity pattern after hypophysectomy in young (40 days) and adult (180 days) rabbits. In the young animals, Sm activity decreased a little, but the serum remained slightly active. The serum of the older rabbits progressively lost its sulphation activity and inhibited SO4 uptake after 2 weeks following hypophysectomy. The inhibitory activity could not be destroyed by heating. Concomitantly, the same serum continued to stimulate thymidine uptake. From the present results on bioactivity, it appeared that Sm generation was only partially pituitary-dependent, that the pituitary might control inhibitor synthesis, and that the SO4 and thymidine factors were separate entities, each having its own inhibitor(s).

Age Factors↗

PubMed1984

Effects of diabetes on glucose oxidation in rat aorta after hypophysectomy and adrenalectomy.

The influence of diabetes, hypophysectomy and adrenalectomy on glucose oxidation in rat aorta was studied. Diabetes was induced in normal, adrenalectomized and hypophysectomized-cortisone substituted rats by streptozotocin (65 mg/kg body weight). The oxidation of glucose to CO2 was determined during incubation of rat aorta in vitro for 2-3 hours. The aortic glucose oxidation was reduced after hypophysectomy but was unaffected by adrenalectomy. After streptozotocin treatment the rise in blood glucose concentration was similar in normal, adrenalectomized and hypophysectomized-cortisone substituted rats. In shamoperated diabetic rats the aortic glucose oxidation was reduced after a diabetes duration of 4 days. In adrenalectomized diabetic rats the aortic glucose oxidation was not significantly affected after 4 days but was reduced after a diabetes duration of 14 days. When adrenalectomized diabetic rats were treated with hydrocortisone the aortic glucose oxidation was reduced after diabetes for 4 days. After incubation of normal rat aorta in vitro for 6 hours with cortisol (1 microgram/ml) in the incubation medium a decrease in the aortic glucose oxidation was found. Incubation of aorta with only growth hormone had no effect. These results suggest that cortisol is of importance for the lowered glucose oxidation in diabetic rat aorta.

3-Hydroxybutyric Acid↗

PubMed1983

Effect of hypophysectomy and administration of TSH on the activity of monoamine oxidase in the thyroid gland of rats.

The thyroid monoamine oxidase (MAO) activity was measured in rats after hypophysectomy and TSH treatment to find out whether the thyroid MAO activity can be modified with TSH. Hypophysectomy decreased MAO activity in the thyroid gland of rats. The administration of TSH (2.5 U kg-1 daily for 5 days) to hypophysectomized rats increased MAO activity and fully compensated the absence of the pituitary. These data suggest that the thyroid gland MAO activity is under the regulatory influence of TSH.

Animals↗

PubMed1993

Tumors of the nasal cavity occurring after hypophysectomy.

Olfactory neuroblastoma and malignant melanoma of the nasal cavities as second primary tumors after resection of pituitary adenomas in two patients are described. These cases, which seem to be the first documented in the literature, demonstrate the problems in diagnosis and treatment. Because of its rare occurrence, a second primary tumor may not be suspected when symptoms develop in the region of a previous hypophysectomy. A close follow-up after hypophysectomy for pituitary adenoma is recommended for the early detection of a second primary tumor. Pathogenetic considerations are discussed.

Aged↗

PubMed1999

Endoscopic pituitary surgery: an in vivo model for transnasal transsphenoidal hypophysectomy.

The transseptal transsphenoidal approach to surgical intervention of the pituitary gland has been described for decades. Its gradual acceptance as the standard of therapy is indicative of general trends toward less invasive means of managing intracranial surgical disease. The evolution of the technique has coincided with advances in medical technology, including the introductions of intraoperative fluoroscopy and operative microscopy. Current progress in the field of endoscopy promises to further this evolution: endoscopic telescopes and instruments have improved on the optical and technical limitations of the microscope and require an even less invasive approach to the sella. To test the benefits and limitations of the endoscope in performing transnasal transsphenoidal hypophysectomy in an in vivo model, we operated on two live anesthetized pigs using 4.0-mm 0- and 30-degree 18-cm long endoscopes. The long lengths of the pig snouts precluded a transnasal approach to the sella; however, we were able to use the endoscopes to explore the sphenoid sinus, sella turcica, and parasellar regions via a transoral exposure. Digital images of the relevant skull base anatomy were captured. The benefits and limitations of the technique were noted and compared with our experience with microscopy in transsphenoidal hypophysectomy in humans.

Animals↗

PubMed1983

Regulation of prolactin secretion in the pregnant pig: effect of fetal hypophysectomy and fetal death in small litters.

Fetal effects on prolactin secretion in late pregnancy and at term were studied in gilts with small litters of intact, hypophysectomized, partially hypophysectomized or dead fetuses. Litter size was reduced at surgery at Days 30-40 of gestation and fetal hypophysectomy or sham procedure attempted on Days 90-95 of gestation using an electrocoagulating probe. Plasma prolactin concentrations rose markedly before parturition in three gilts with normal litters (P = 0.05) and to lower peak concentrations in two gilts with a single fetus. Plasma prolactin did not change from basal concentrations in 4 gilts with small litters (1-2 fetuses) of hypophysectomized fetuses or, in 2 gilts with dead fetuses. Basal plasma prolactin concentrations were significantly lower in gilts carrying hypophysectomized or dead fetuses, compared to normal gilts (P = 0.01). A surge of prolactin secretion preceded delivery in 2 gilts with fetuses with incomplete hypophysectomy and in 1 gilt with 1 of 3 hypophysectomized fetuses. Abnormal patterns of prolactin secretion were seen in 1 gilt with 3 of 5 hypophysectomized fetuses and in 1 gilt with 1 partially hypophysectomized fetus. The results suggest that the fetus may be associated with a mechanism regulating plasma prolactin concentration at term. It is possible that this association may be by way of the fetal pituitary endocrine axes, and/or a function of conceptual mass.

Animals↗

PubMed1987

Effects of photoperiod, hypophysectomy, and follicle-stimulating hormone on testicular follicle-stimulating hormone binding sites in golden hamsters.

Experiments were conducted to partially characterize and to examine the regulation of unoccupied testicular follicle-stimulating hormone (FSH) binding sites in adult golden hamsters. Testicular FSH binding sites were measured in the 1800 X gav fraction of whole testicular homogenates using iodinated bovine FSH. Binding of FSH was highly specific for FSH, located primarily in the testes, was time- and temperature-dependent, initially reversible, saturable, and consistent with a model consisting of a single class of high-affinity binding sites (range of equilibrium association constants (Ka) 2-12 X 10(10) M-1). Exposure of hamsters to a short photoperiod consisting of 5L:19D was associated with an increase in concentration (fmol/mg protein), but a reduction in total content (fmol/testes) of testicular FSH binding sites. There was no appreciable 5L:19D-associated alteration in receptor affinity (average Ka = 7.83 X 10(10) M-1). Injections of ovine prolactin (oPRL), ovine luteinizing hormone (oLH), or ovine FSH (oFSH) for 3 days into hamsters housed in 5L:19D for 12 wk had no effect on photoperiod-induced changes in testicular FSH binding sites. On Days 5 and 6 post hypophysectomy, a dramatic increase in FSH binding site concentration occurred, with but marginal effects on binding site affinity. Injections of 5 micrograms oFSH on Days 2, 3, and 4 after hypophysectomy prevented the increase in binding site concentrations measured on Day 5. Injection of a combination of 5 micrograms oFSH, 50 micrograms oPRL, and 25 micrograms oLH also reduced testicular FSH binding site concentrations in hypophysectomized hamsters, but oPRL or oLH by themselves were ineffective. The data indicate a homologous down-regulation of testicular FSH binding sites, but do not exclude the involvement of other hormones.

Animals↗

PubMed1989

Proluminal movement of 3H-androgen across the epididymal epithelium in the rat after hypophysectomy and gonadotropin supplementation.

The effects of hypophysectomy and gonadotropin replacement on transepithelial movement of 3H-androgen in the rat epididymis were examined by in vivo microperifusion of 3H-testosterone followed by in vivo micropuncture to obtain peritubular and intraluminal fluid. In the caput epididymidis of normal rats, intraluminal 3H-androgen concentrations were approximately 300% of those in the interstitial space. In contrast, proluminal movement of 3H-androgen into rat caput epididymal tubules was significantly decreased 10 days after hypophysectomy. 3H-Testosterone movement across the caput epididymal epithelium was completely returned to normal by supplementation with 24 micrograms/day follicle-stimulating hormone (FSH) or 24 micrograms/day luteinizing hormone (LH). However, neither 0.12 micrograms/day FSH nor 250 micrograms/day prolactin returned proluminal androgen movement to normal. It is speculated that epididymal uptake of peritubular testosterone is mediated by androgen-binding protein, which is known to be secreted by Sertoli cells after stimulation by FSH or testosterone.

Animals↗

PubMed1976

Hypophysectomy in the treatment of disseminated carcinoma of the breast and prostate gland.

Transsphenoidal hypophysectomy offers gratifying palliative relief of pain to patients with metastatic cancer of the breast and prostate. This report represents the results of two years' experience with this procedure at Emory University School of Medicine. The physiologic rationale and clinical indications for hypophysectomy are described, as is the operative technic using the open transsphenoidal microsurgical approach. The series of cases reported here includes 20 men with disseminated prostatic carcinoma and 23 women and one man with metastatic carcinoma of the breast. All 44 procedures were done by the transsphenoidal microsurgical approach. Pain was the preoperative indication for surgery in 41, while three patients were operated on for extensive disease without pain. Satisfactory relief of pain was obtained in 76% of the patients with prostatic cancer and in 83% of the breast cancer patients. While the results are gratifying with regard to relief of pain, the duration of follow-up is not sufficient to comment on the value of the procedure in significantly prolonging life.

Adult↗

PubMed1981

Transsphenoidal hypophysectomy in disseminated breast cancer.

Sixty patients with metastatic breast cancer had transsphenoidal hypophysectomy at Emory University Hospital. Median survival for the entire group was ten months. Survival was increased (longer than 14 months) in good responders as compared to nonresponders (three months). Pain was significantly relieved in the majority of those patients who had severe pain. Operative complications were minimal. The technic of transsphenoidal hypophysectomy offers a substantial chance of objective and subjective palliation with minimal morbidity in advanced breast cancer.

Adult↗

PubMed1975

Treatment of acromegaly by transsphenoidal hypophysectomy with cryoapplication.

The therapeutic effect of transsphenoidal hypophysectomy with cryoapplication has been studied in twenty-nine patients with active acromegaly. The mean follow-up time was 15 months (354 months). A significant improvement of symptoms and signs occurred in all but three patients. The level of plasma immunoreactive growth hormone (IRGH) was reduced in all but two patients and a normal level of plasma IRGH was achieved in sixteen patients. Skin thickness, the level of serum inorganic phosphorus and the urinary excretion of hydroxyproline and calcium were significantly decreased in the great majority of the patients. The operation was not accompanied by any visual complications, but cerebrospinal rhinorrhoea, subsiding spontaneously, developed in two and postoperative meningitis in one patient. Hypothyroidism and adrenocortical deficiency developed in eight, gonadotrophin deficiency in thirteen, and persistent diabetes insipidus in one patient. It is concluded that transsphenoidal hypophysectomy with cryapplication is a safe and effective method for the treatment of acromegalic patients.

Acromegaly↗

PubMed1992

Low recurrence rate after partial hypophysectomy for prolactinoma: the predictive value of dynamic prolactin function tests.

OBJECTIVE: To determine the factors influencing the outcome of transethmoidal partial hypophysectomy for suspected prolactinoma and the predictive value of pre and post-operative dynamic PRL function tests. DESIGN: A retrospective study of patients undergoing surgery for a suspected prolactinoma in Cardiff between 1979 and 1989. PATIENTS: Eighty-two hyperprolactinaemic patients (75 women, seven men) diagnosed as having a prolactinoma on the basis of dynamic PRL function tests, radiological investigation and exclusion of other causes. MEASUREMENTS: TSH and PRL responses to domperidone (10 mg i.v.) and TRH (200 micrograms i.v.) measured preoperatively, 2 months post-operatively, and annually thereafter. CT scan performed preoperatively in 58 patients. Operative findings, including adenoma size, documented in each case. RESULTS: Forty-two patients (51%) had microadenomas (less than 10 mm), 37 (46%) had macroadenomas and in three no tumour was found at operation. Preoperatively, normal responses of both TSH (incremental rise less than 2.0 mU/l) and PRL (greater than 100% rise) to domperidone were observed in two patients only: both had an abnormal vascular supply to the pituitary rather than an adenoma. Serum PRL was normalized in the early post-operative period (less than 72 h; 'early cure') in 65 patients (79%). The highest early cure rate (96%, n = 26) was in patients with adenomas of 5-9 mm, lower rates being achieved for lesions of 10-19 mm (80%, n = 30), less than 5 mm (63%, n = 19) or greater than or equal to 20 mm (57%, n = 7). The early cure rate was strongly correlated with preoperative PRL, ranging from 100% in patients with PRL less than 1000 mU/l (n = 13) to zero in those with PRL greater than 10,000 mU/l. Dopamine agonist therapy of between 5 weeks and 4 years duration prior to surgery was associated with a significantly reduced early cure rate (60 vs 94%, P less than 0.02) in macroadenoma but not microadenoma patients. Recurrent hyperprolactinaemia during mean follow-up of 51.7 months occurred in eight patients (12%), in five cases within 2 months of surgery and in the others at 26, 48 and 50 months. Recurrence could not be predicted from any preoperative parameter, but a serum PRL greater than 150 mU/l 1-3 days following microadenomectomy was associated with early recurrence and probably indicates failed surgery. An abnormal response of TSH to domperidone was documented 2 months post-operatively in 11/60 patients with normal basal PRL, and preceded all three late recurrences. Of four patients with abnormal responses of both PRL and TSH at this time, two have relapsed to date. CONCLUSIONS: In carefully selected patients, partial hypophysectomy is an acceptable alternative to medical treatment for prolactinoma. Preoperatively, dynamic tests accurately identified those patients whose hyperprolactinaemia was non-adenomatous in origin and, post-operatively, identified a subgroup of patients at increased risk of late recurrence.

Adult↗