ACTH-producing Adenoma Research Articles

Subchondral fractures of the femoral head: a review of seven cases

Objective. – To describe the main characteristics of subchondral fractures of the femoral head. Case-Reports. – The seven patients, five women and two men, with a mean age of 50 years (37–76 years), presented with mechanical pain in the groin. Bone loss was the main risk factor. Two patients had postmenopausal osteoporosis (including one with a history of ovariectomy at 30 years of age), two had osteoporosis induced by glucocorticoid therapy given after transplantation (liver and allogeneic bone marrow, respectively), one had an ACTH-producing adenoma, and one had femoral osteopenia at a site of topical glucocorticoid therapy for atopic dermatitis. The remaining patient had osteopenia and a history of smoking. Phosphate and calcium levels were normal in five patients. One patient had isolated hypocalciuria and another had moderate proximal tubular disease with phosphate wasting and hypercalciuria. Magnetic resonance imaging (MRI) disclosed a subcapital line of low signal on T1- and T2-weighted sequences surrounded by an area of variable size generating low signal on T1 images and high signal on T2 images, with postgadolinium enhancement, denoting marrow edema. Complete elimination of weight bearing for 6 weeks, symptomatic agents, and treatment of the underlying causes of bone insufficiency were used in all seven patients. Mean follow-up was 2.4 years (range, 11–39 years). No cases of osteonecrosis were recorded. Conclusion. – Several cases of subchondral fracture have been reported in the literature. Bone insufficiency was the main risk factor in all the patients.

Expression of hypoxia-inducible factor-1alpha (HIF-1alpha) in pituitary tumours.

The present study was performed to investigate HIF-1alpha (hypoxia-inducible factor-1alpha) expression in a large number of immunohistochemically and ultrastructurally characterized surgically removed pituitary tumours. The potential relation of HIF-1alpha with outcome variables as well as the presence of HIF-1alpha expression in the tumours treated with dopamine agonists and octreotide, a long-acting somatostatin analogue was also investigated. HIF-1alpha immunoreactivity was confined to the nucleoplasm whereas the nucleoli were unconspicuous. The distribution of HIF-1alpha was evident in the tumours whereas normal adenohypophysial cells showed no HIF-1alpha staining. HIF-1alpha expression was detected not only in the tumour cells but also in endothelial cells lining the blood vessels within the tumour. ACTH producing adenomas showed the lowest level of HIF-1alpha expression whereas pituitary carcinomas and GH producing adenomas had the highest counts. The statistical study demonstrated no significant correlation between HIF-1alpha expression, patient age, gender, tumour, size, invasiveness, cell proliferation rate and vascularity. These results suggest that the behaviour of pituitary tumours does not primarily depend of HIF-1alpha expression. Our study demonstrated an increase HIF-1alpha expression in bromocriptine treated PRL producing pituitary adenomas compared with untreated tumours but no increase in octreotide treated tumours.

Expression of CRF1 and CRF2 receptors in human cancers.

Overexpressed peptide receptors in human tumors represent clinically relevant targets for cancer diagnosis and therapy. Corticotropin-releasing factor (CRF) and its receptors have not been known to be involved in human cancer. The aim of the present study was to investigate such possibility by evaluating the expression of CRF(1) and CRF(2) receptors using in vitro autoradiography with subtype-selective CRF analogs in more than 200 primary human cancer samples. We show that a majority of pituitary adenomas express CRF receptors, often in high amounts. Whereas ACTH-producing adenomas preferentially express CRF(1) receptors, nonfunctioning adenomas (gonadotropin-producing and null-cell adenomas) and GH- and TSH-producing adenomas express CRF(2) receptors. Furthermore, several central and peripheral nervous system tumors express CRF receptors: medulloblastomas, paragangliomas, neuroblastomas, and some meningiomas express CRF(1) receptors, but ependymomas or Ewing sarcomas do not. Insulinomas can also express CRF receptors, whereas ductal pancreatic cancers or prostatic, colorectal, and non-small cell lung cancers lack CRF receptors. In all receptor-positive tumors, the receptors were located on tumor cells. The high incidence of CRF(1) or CRF(2) receptors in selected human tumors suggests that unlabeled CRF agonists may be evaluated as inhibitors of tumor cell proliferation in cancer therapy, and radiolabeled CRF analogs may be used for cancer diagnosis and/or radiotherapy.

Successful Treatment of Pituitary Macroadenoma with Transsphenoidal Hypophysectomy in a Dog

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.

Topoisomerase IIα Expression in Pituitary Adenomas and Carcinomas: Relationship to Tumor Behavior

DNA topoisomerase IIα (Topo IIα) is a molecular and immunohistochemical marker that indicates proliferation rate and is the target for several antineoplastic agents. The present immunohistochemical study of a large series of surgically removed pituitary tumors was designed to assess the prognostic significance of Topo IIα expression relative to patient age, gender, tumor type and size, invasiveness, metastasis, MIB-1–labeling index and angiogenesis. Changes of Topo IIα expression in the tumors treated with bromocriptine and octreotide, a long-acting somatostatin analogue were also investigated. Topo IIα immunopositivity was detected only in the nuclei of tumor cells. Gonadotroph adenomas, null cell adenomas, and ACTH-producing adenomas had the lowest Topo IIα indices, whereas primary pituitary carcinomas and silent type 3 adenomas presented the highest counts. The statistical study demonstrated no significant correlation between Topo IIα expression, patient gender, and vascularity. In contrast, significant negative correlation was found between Topo IIα expression and patient age. Topo IIα expression was significantly higher in invasive than noninvasive tumors. A tendency to have higher counts was also observed in microadenomas compared with in macroadenomas. Although Topo IIα and MIB-1 indices were similar in most tumor types, no significant correlation between Topo IIα and MIB-1–labeling indices (r = .16, P = .09) was found. Only non-functioning adenomas showed positive correlation (r = .41, P = .006) between both proliferation markers. Our results demonstrated a significant decrease in Topo IIα index in octreotide-treated, GH-producing adenomas, compared with untreated tumors, but no significant changes were observed in bromocriptine-treated, PRL-producing adenomas. The present study showed no significant advantage of Topo IIα over MIB-1 as a prognostic marker; however, Topo IIα may provide crucial information regarding selection of adenohypophyseal tumors responsive to antineoplastic therapy, such as invasive pituitary adenomas and pituitary carcinomas, which exhibit a high Topo IIα index.

Management of Cushing's Disease: An Update

Most cases of hypercortisolemia seen in the adult population are caused by microadenomas of the anterior pituitary gland.[1] [19] Cushing's disease is the life-shortening illness caused by hypercortisolism secondary to an adrenocorticotropic hormone (ACTH)-secreting pituitary adenoma. More than any other secretory tumor of the pituitary gland, the basophilic ACTH-producing adenoma responsible for Cushing's disease continues to provide the clinician with diagnostic and therapeutic challenges. Recent advances in surgical strategy, endocrinologic assessment, and adjuvant therapies have improved the surgeon's ability to treat this medically devastating disease.

Glial-derived neurotropic factor and RET gene expression in normal human anterior pituitary cell types and in pituitary tumors.

Glial-derived neurotropic factor (GDNF) signaling is mediated through a 2-component system consisting of the so-called GDNF receptor-alpha (GFRalpha1), which binds to GDNF. This complex activates the tyrosine kinase receptor RET. In this paper we demonstrate GDNF, GFRalpha1, and RET mRNA and protein expression in the human anterior pituitary gland. Double immunohistochemistry of anterior pituitary sections showed GDNF immunoreactivity in more than 95% of somatotrophs and to a lesser extent in corticotrophs (20%); it was almost absent in the remaining cell types. Also, although more than 95% of somatotrophs were stained for RET, no positive immunostaining could be detected in other cell types. Furthermore, we have looked for GDNF and RET in human pituitary adenomas of various hormonal phenotypes. Strong positive immunostaining was found for c-RET in all of the GH-secreting adenomas screened as well as in 50% of ACTH-producing adenomas. Positive immunostaining for GDNF was found in all of the GH-secreting adenomas and in 10% of the corticotropinomas. Lastly, we found strong positive immunostaining for GFRalpha1 in 90% of the somatotropinomas and 50% of the corticotropinomas as well as in 1 of 8 prolactinomas and 1 of 13 nonfunctioning adenomas. All of the remaining pituitary tumors screened were negative for RET, GDNF, and GFRalpha1. This study indicates that GDNF may well be acting in the regulation of somatotroph cell growth and/or cell function in the normal human anterior pituitary gland. The expression of RET in all of the somatotropinomas and in 50% of the ACTH-producing tumors implies that GDNF and RET could be involved in the pathogenesis of pituitary tumors.

Galanin in human pituitary adenomas: frequency and clinical significance.

Galanin (GAL) is a neuropeptide widely expressed in the central and peripheral nervous system and in neuroendocrine tissue, including the adenohypophysis where, in humans, it is expressed in corticotrophs and in ACTH-producing adenomas. Previous analyses of human tissue have used antiserum against porcine GAL for detection of GAL immunoreactivity (GAL-IR) and no pathophysiological correlates have been reported. Given significant differences between the sequence of porcine and human GAL peptides, the aim of this study was to use antiserum raised against synthetic human GAL to investigate GAL-IR in non tumorous pituitaries and in pituitary adenomas, and to correlate GAL-IR with the clinical and hormonal characteristics of patients with Cushing's disease. Six nontumorous pituitaries were obtained from autopsy and 151 pituitary adenomas, comprising 62 functioning (16 corticotroph, 26 somatotroph, 19 lactotroph and one thyrotroph) and 89 nonfunctioning adenomas, were obtained by surgery. All non tumorous pituitary glands showed GAL-IR in corticotrophs, in basophil cells within the neurohypophysis and in nerve fibres of the neurohypophysis. GAL-IR was found in a subset (10 of 16) of patients with ACTH-secreting tumours causing Cushing's syndrome. GAL-IR was rarely expressed in somatotroph adenomas and prolactinomas, but was expressed in approximately one-third of nonfunctioning tumours. GAL-IR was found in almost 90% of nonfunctioning tumours that were positive for ACTH. There were no significant differences in sex ratio, age at presentation or 24-h urinary free cortisol secretion in the subset of patients with Cushing's disease positive (n = 10) or negative (n = 6) for GAL-IR. However, Cushing's patients positive for GAL-IR tended to have smaller tumours and achieved a higher cure rate than those without (100 vs. 50%, P = 0.017). Galanin is present in normal and tumorous human pituitaries. In addition, GAL colocalizes exclusively in corticotrophs of normal pituitaries and is coexpressed almost exclusively in corticotrophs from functioning and nonfunctioning tumours. The finding that corticotroph adenomas can function irrespective of the presence of GAL suggests that GAL may not play a pathophysiological role in Cushing's disease. However, the better surgical outcome observed in patients with Cushing's disease who had tumours positive for GAL-IR suggests that the expression of GAL confers a less aggressive tumour phenotype.

Ghrelin and growth hormone (GH) secretagogue receptor (GHSR) mRNA expression in human pituitary adenomas.

The level of growth hormone (GH), growth hormone secretogogue (GHS) and GHS receptor (GHSR) messenger ribonucleic acid (mRNA) expression has been reported as being higher in GH-producing pituitary adenomas than in other types of pituitary adenomas. Recently, ghrelin, an endogenous ligand specific for GHSR, was isolated. Therefore, we attempted to clarify whether ghrelin mRNA is expressed in various types of human pituitary adenoma by competitive reverse transcription-polymerase chain reaction (RT-PCR). We also examined the relationship between the levels of ghrelin or GHSR mRNA and hormonal and tumour characteristics in patients with pituitary adenomas. Pituitary adenoma tissue was obtained at surgery from 13 patients with acromegaly, 4 with prolactinomas, 5 with gonadotrophin (Gn)-producing adenomas, 4 with non-functioning adenomas, 2 with ACTH-producing adenomas and 2 with TSH-producing adenomas. The expression levels of human ghrelin mRNA and GHSR mRNA were quantified using a competitive RT-PCR method. Ghrelin mRNA was detected in all pituitary adenoma tissues examined, with the highest mean level detected in non-functioning adenomas, a moderate level in GH-producing adenomas and Gn-producing adenomas, and the lowest level in prolactinomas. The level of ghrelin mRNA expression in GH-producing adenomas correlated negatively with the size of the adenoma (n = 13) (r = - 0.756, P = 0.0028). Furthermore, the mean level of ghrelin mRNA expression in high-grade (III and IV of Hardy classification) GH-producing adenomas was significantly lower than that in low-grade (I and II) GH-producing adenomas (P = 0.0016). GHSR mRNA was also detected in all pituitary adenomas with the highest mean level in GH-producing adenomas, a moderate level in nonfunctioning adenoma, and the lowest level in prolactinoma and Gn-producing adenomas. Ghrelin mRNA, in addition to GHSR mRNA, is expressed in various types of pituitary adenoma with different levels of expression in each type. Our findings suggest that ghrelin produced in pituitary adenoma may play some role in the mechanism underlying the development of adenoma cells through autocrine and/or paracrine pathways.

Long-term results of radiation therapy for pituitary adenoma.

Local control for pituitary adenomas treated with external beam radiation therapy was retrospectively analyzed to evaluate the efficacy of radiation. Thirty-eight patients treated with radiation therapy between 1979 and 1994 were analyzed. The median age was 46. Nineteen newly diagnosed tumors were treated with surgery and radiation therapy, while the others were recurrent cases. Twenty-two tumors were non-functioning, while 10 produced growth hormone (GH) and three each were prolactin-, and adrenocorticotropic hormone (ACTH)-producing tumors. The median-radiation dose was 50 Gy in 25 fractions. Non-functioning adenomas and prolactin-producing adenomas were completely controlled, judging from the absence of tumor progression on neuroimaging studies and clinical symptoms, and normalization of the serum prolactin level (< 25 ng/ml). On the other hand, local control was obtained in only one of the 3 patients with ACTH-producing adenomas, and the control rate at 10 years was only 46% for GH-producing adenomas. Panhypopituitarism developed in 35% of the patients after radiation therapy. No other serious complications were noted. Non-functioning pituitary adenomas and prolactin-producing adenomas were well controlled with external radiation therapy combined with surgery. However, dose escalation might be necessary to control GH-or ACTH-producing tumors. It is important to replace corticosteroid hormone and thyroid hormone in many patients.

Pituitary Adenomas Treated by Microsurgery with or without Gamma Knife Surgery: Experience in 122 Cases

The clinical outcome of 122 patients with pituitary adenomas treated by microsurgery and/or Gamma Knife radiosurgery (GKRS) was analyzed to evaluate patient selection criteria and the role of GKRS. Sixty-six resections were performed in 59 patients. All tumors were macroadenomas, except for 5 ACTH-producing adenomas. Twenty-four of the 31 hypersecreting adenomas showed normal serum hormone values after treatment. Postoperative complications were rhinorrhea, cranial nerve palsies, and a small thalamic infarct. GKRS was performed on 18 of the operated patients because of residual tumors, mostly in the cavernous sinus. Thirty-five of the 63 patients treated by GKRS were followed for more than 2 years. All adenomas except 2 were stable or had decreased in size. Eleven of 17 functioning adenomas showed normal serum hormone values after treatment. It is concluded that tumors that compress the optic pathway should be removed and that residual tumors in the cavernous sinus are good indications for radiosurgery.

Immunohistochemical demonstration of oncocytes in nongonadotrophic pituitary adenomas.

An immunohistochemical study to demonstrate oncocytes in nongonadotrophic pituitary adenomas was performed. The adenomas were 10 prolactinomas, 2 ACTH-producing adenomas (ACTHomas), and 28 growth hormone-producing adenomas (GHomas); we also studied 5 pituitary oncocytomas. GHomas were divided into two groups: GHomas with (GHomas-1) and without (GHomas-2) fibrous bodies. A small number of solitary large cells showed intense cytoplasmic granular reactivity for mitochondrial protein and cytochrome oxidase, resembling oncocytes in oncocytomas. The proportions of the mitochondrial protein-positive cells ranged from zero to 2.1% (0. 3+/-0.4%). They were more frequent in GHomas, GHomas-1 in particular, than other types of adenomas (P<0.01), and were mostly negative in prolactinomas and ACTHomas. In multivariate analysis, the proportions showed positive correlation with age (P<0.01) and the Ki-67 (MIB-1) labeling index (P<0.01) and tended to increase in number with recurrence (P<0.05). In GHomas, these cells were more common in cases with low basal GH level (P<0.01) and large tumor volume (P<0.01). We consider that these cells represent oncocytes existing in varying numbers in adenomas. We suggest that oncocytic change in nongonadotrophic adenomas indicates poor differentiation and/or some aggressiveness, which lead to a decrease in the endocrine activity of the tumor.

Prop-1 gene expression in human pituitary tumors.

A novel type of pituitary-specific transcription factor, Prophet of Pit-1 (Prop-1) gene (PROP1), expresses in just early embryonic stage in mouse and closely related as a causative gene in combined pituitary hormone deficiency. We studied PROP1 expression to further clarify its correlation with tumorigenesis and biological behavior in human pituitary adenomas. Eighteen pituitary adenomas and three normal pituitary glands were examined for the expression of PROP1 and POU1F1 by using RT-PCR Pituitary adenomas were diagnosed as non-functioning adenomas (n = 11), prolactinomas (n=5), GH-producing adenoma (n = 1) and ACTH-producing adenoma (n = 1). One of non-functioning adenomas was pituitary carcinoma with cerebellar metastasis and CSF dissemination. Our results demonstrated PROP1 expression in all pituitary tumors examined, in contrast, POU1F1 was detected in 14 of pituitary tumors. PROP1 was also expressed in normal pituitary gland, however, it was not in normal brain tissue, glioblastomas (cell lines and tumor tissues) and meningioma. Our data indicated that PROP1 expression was observed constantly both in the pituitary tumors and normal human adult pituitary tissues, suggesting that PROP1 is an essential transcriptional factor for pituitary specific gene expression in human. Therefore, detection of PROP1 might be a useful indicator for differentiating pituitary adenomas, regardless of their hormonal phenotypes, from other brain tumors.

Low level of glucocorticoid receptor messenger ribonucleic acid in pituitary adenomas manifesting Cushing's disease with resistance to a high dose-dexamethasone suppression test.

The overnight 8-mg dexamethasone suppression test is often used to differentiate Cushing's disease, due to an oversecretion of ACTH from the pituitary gland, from other kinds of Cushing's syndrome. However, a few patients with ACTH-producing pituitary adenoma show no suppression of plasma cortisol after the administration of 8 mg of dexamethasone. To clarify the relationship between the level of glucocorticoid receptor (GR) in the pituitary adenoma and the sensitivity to dexamethasone in Cushing's disease, we thus examined the levels of GR alpha and GR beta mRNAs in the pituitary adenomas in six patients who were proven at surgery to have pituitary ACTH-producing adenomas. Total RNA was extracted from six pituitary adenomas and pituitary tissue adjacent to one of the adenomas, and the mRNA levels of GR alpha, GR beta, pro-opiomelanocortin (POMC) and beta-actin in these samples were sampled by quantitative RT-PCR. The GR alpha mRNA levels in the adenomas from the two patients who showed no response to the 8-mg dexamethasone suppression test were significantly lower than those in the adenomas of four patients who showed suppression. The GR beta mRNA level was much lower than that of GR alpha mRNA but not significantly different among the six adenomas. These results suggest strongly that decreased expression of GR alpha in pituitary adenomas may be the major reason for the marked insensitivity to the 8-mg dexamethasone suppression test observed in two patients with Cushing's disease.

Elevated proenkephalin-derived peptide levels in ACTH-producing adenomas: nucleus and cytoplasm localization.

The biosynthesis of met-enkephalin in human pituitary and human pituitary adenomas is still not well known. In this work, we studied the processing of proenkephalin-derived peptides in postmortem human pituitary (PMHP), ACTH-producing adenomas (ACTH-PA), nonfunctioning adenomas (NFA), and GH-producing adenomas (GH-PA). ACTH-PA contained at least 10 times more proenkephalin-derived peptides than PMHP, NFA,and GH-PA. Proenkephalin processing was different in the four tested tissues. In ACTH-PA, proenkephalin was processed to high-, intermediate-, and low-mol-wt products. The highest met-enkephalin-containing peptides levels corresponded to intermediate and low-mol-wt materials, although met-enkephalinArg-Phe and synenkephalin immunoreactivity appeared only in high-mol-wt peptides. In PMHP and NFA, met-enkephalin-Arg-Phe immunoreactivity was detected in intermediate- and low-mol-wt materials, and it was absent in GH-PA. Immunoblotting of ACTH-PA showed that met-enkephalin-Arg-Phe immunoreactivity corresponded to peptides of 44, 32-30, 27, and 17 kDa. The 32-30 and 17-kDa molecules were localized in the nuclear fraction where they were extracted after enzymatic digestion with DNase I. Plasmatic met-enkephalin levels did not increase in patients with Cushing's disease, suggesting that the pentapeptide stored in ACTH-PA was not released to the general circulation. In conclusion, we demonstrated that only ACTH-PA contained high levels of proenkephalin peptides, which were stored in cytoplasm organelles and in the nucleus, probably bound to chromatin. These results suggest an adenoma-specific physiological role of proenkephalin products.

Urocortin expression in human pituitary gland and pituitary adenoma.

Urocortin is a recently identified neuropeptide of the CRF family in the mammalian brain, but its expression in human tissue has been little studied. In this study, we examined urocortin expression in human anterior pituitary gland and pituitary adenomas by RIA, high performance liquid chromatography, immunohistochemistry, messenger ribonucleic acid (mRNA) in situ hybridization, and reverse transcriptase-PCR. Immunoreactive urocortin concentrations in normal pituitary tissue extract were 103.25 +/- 39.05 ng/g wet wt (mean +/- SEM; n = 4), and their levels were all significantly higher than those in other portions of central nervous system of the same subjects. High performance liquid chromatography analysis of human pituitary extract demonstrated a single peak corresponding to that of the expected chromatographic mobility of synthetic human urocortin-(1-40). Urocortin-immunoreactive cells were detected in the anterior pituitary gland. Neither urocortin-immunoreactive nerve fibers nor cells were detected in the posterior lobe. Immunostaining in serial mirror tissue sections revealed that 76.55 +/- 3.06% of urocortin-immunoreactive cells expressed GH immunoreactivity, whereas 22.25 +/- 3.02% and less than 1% of urocortin-immunoreactive cells expressed PRL and ACTH, respectively. mRNA hybridization signals of urocortin were also detected in urocortin-immunopositive pituitary cells. The reverse transcriptase-PCR analysis demonstrated a 145-bp RNA band corresponding to that of the expected length of urocortin in all cases of normal pituitary glands examined (n = 3). We also immunostained urocortin in 52 cases of human anterior pituitary adenomas, including GH-producing adenomas (n = 14), ACTH-producing adenomas (n = 13), PRL-producing adenomas (n = 11), and nonfunctioning hormonally inactive adenomas (n = 14). No urocortin immunoreactivity was detected in these adenoma cells, except for one case of GH-producing adenoma and one case of nonfunctioning adenoma. We also performed mRNA in situ hybridization in 27 adenomas. No hybridization signals were detected in these adenomas, except in two cases. The results described above indicated that urocortin is synthesized in human anterior pituitary cells and may play an important role in biological features of normal pituitary gland, possibly as an autocrine or a paracrine regulator

Gonadotropin-releasing hormone and gonadotropin-releasing hormone receptor messenger ribonucleic acids expression in nontumorous and neoplastic pituitaries.

In the nontumorous pituitary, GnRH stimulates the release and synthesis of LH and FSH by gonadotroph cells via the GnRH receptor (GnRH-R). Little is known, however, about expression of GnRH and GnRH-R messenger RNAs (mRNAs) in nontumorous pituitary tissue and in adenomas. To learn more about the distribution and regulatory roles of GnRH and its receptor, we investigated the expression of both GnRH and GnRH-R mRNAs in nontumorous human pituitary and in various types of pituitary adenomas using the RT-PCR, in situ hybridization, and in situ hybridization in combination with RT-PCR (in situ RT-PCR). Using RT-PCR, GnRH mRNA was found to be expressed in normal human pituitaries and in all types of adenomas. Similarly, GnRH-R mRNA was expressed in nontumorous human pituitaries and in most, but not all, adenomas. These included 5 gonadotroph adenomas, 6 null cell adenomas, 1 of 2 GH-producing tumors, and 1 of 2 ACTH-producing adenomas, but not in the 2 PRL-producing adenomas examined. In situ hybridization studies showed GnRH and GnRH-R mRNAs in all 3 nontumorous pituitaries and in 12 of 33 (36.4%) and 10 of 33 adenomas (30.3%), respectively. Using an indirect in situ RT-PCR technique to increase the sensitivity of the in situ localization, GnRH and GnRH-R mRNAs were detected in 29 (87.9%) and 25 (75.8%) of 33 adenomas, respectively. This is the first report of the localization of GnRH and GnRH-R mRNAs in individual pituitary adenoma cells using in situ RT-PCR. The frequent expression of GnRH and GnRH-R mRNAs in pituitary cells suggests that GnRH has autocrine/paracrine functions in nontumorous and neoplastic pituitary tissues.

CDNA cloning and mRNA expression analysis of the human neuronatin. High level expression in human pituitary gland and pituitary adenomas.

The authors cloned the nearly complete cDNA of human neuronatin with the aid of an expressed sequence tag (EST) database, and analyzed its expression in various human tissues by Northern blot analysis. The nucleotide and deduced amino acid sequences of the human neuronatin showed a high similarity to those of rodents. The Northern blot analysis revealed that the human neuronatin message was expressed predominantly in the fetal brain in the brain-specific manner, but only faintly in the adult brain. Among the various adult human tissues examined, the anterior pituitary gland was shown to be the only place where the neuronatin mRNA was strongly expressed. Intense neuronatin expression was also observed in several human pituitary adenomas, including ACTH-producing, GH-producing, and nonfunctioning adenomas, but hardly detected in other brain tumors.

Follicle stimulating hormone-beta subunit gene is expressed in parallel with a transcription factor Ad4BP/SF-1 in human pituitary adenomas.

A transcription factor Ad4BP/SF-1 is implicated in the differentiation of gonadotrophs in the pituitary gland, but it is not known whether human pituitary cells express this factor. The present study aimed to disclose (1) whether human pituitary adenomas express Ad4BP/SF-1, and (2) if this is the case, what kinds of adenoma express the factor. Total RNA was extracted from 23 pituitary adenomas obtained by transsphenoidal surgery, and subjected to Northern blot analyses using cDNAs of bovine Ad4BP/SF-1, porcine FSH-beta, LH-beta and glycoprotein hormone-alpha (GPH-alpha) subunts as radiolabelled probes. These adenomas included 13 clinically non-functioning adenomas, 1 GH/PRL-producing adenoma, 6 GH-producing adenomas, 2 PRL-producing adenomas and 1 ACTH-producing adenoma. The expression of Ad4BP/SF-1 exactly coincided with the expression of FSH-beta. Thus 5 out of 13 clinically non-functioning adenomas expressed Ad4BP/SF-1 and only these 5 adenomas expressed FSH-beta. Interestingly, only one of the GH-producing adenomas also expressed Ad4BP/SF-1 as well as FSH-beta. GPH-alpha was expressed in 4 non-functioning adenomas and 2 hormonally functioning adenomas, but did not necessarily coincide with Ad4BP/SF-1 expression. None of the 23 adenomas we tested expressed LH-beta, probably because LH-beta-producing adenomas are rather rare. The expression of FSH-beta was parallel with Ad4BP/SF-1 expression, indicating that the expression of Ad4BP/SF-1 is restricted to cells derived from gonadotroph lineages in human pituitary adenomas.

Effect of Surgery on Gonadal Function of Premenopausal Women with Pituitary Adenomas Other Than Prolactinomas.

The effects of surgery on pituitary-gonadal function were investigated in women with pituitary adenomas other than prolactinomas. The subjects were 46 women of premenopausal age with a pituitary adenoma. Twenty tumors were GH producing, 19 were nonfunctioning, and 7 were adrenocorticotropin producing adenomas. The surgery was performed mainly via the transsphenoidal route, with the aim of eradicating the tumor and preserving pituitary function. The menstrual cycle was preserved postoperatively in 9 out of 10 (90%) patients with regular preoperative menstruation. Menstrual disturbance was seen in 36 (78.3%) cases preoperatively. The causative factors for menstrual disturbance were gonadotropin impairment and hyperprolactinemia in GH producing and nonfunctioning adenoma. Excessive hormonal secretion itself is a major causative factor for menstrual disturbance in GH and ACTH producing adenoma. Regular menstruation was restored following surgery in 20 out of 36 (55.6%) patients with menstrual problems. The predicting factors for postoperative recovery of menstruation are: size of adenoma less than 40 mm, period of amenorrhea less than 5 years, and preoperatively preserved gonadotropin secretion. In addition, preoperative hyperprolactinemia was also a predicting factor in women with nonfunctioning adenoma. Thus, even in patients with pituitary adenomas other than prolactinoma, the restoration of menstruation is highly achievable when surgery is performed with attention to preserving pituitary function.