Reversible shrinkage of a growth hormone-secreting pituitary adenoma by a long-acting somatostatin analogue, octreotide

Octreotide acetate (SMS-201-995), a somatostatin analogue, was used to treat an acromegalic patient harboring a growth hormone-secreting pituitary macroadenoma. Intermittent subcutaneous administration of octreotide suppressed growth hormone and insulin-like growth factor-I (IGF-I) levels and ameliorated clinical symptoms. Magnetic resonance imaging performed after 16 weeks revealed a 70% shrinkage of the pituitary mass, with a resultant partially empty sella turcica. To document that this shrinkage occurred as a result of octreotide treatment and not spontaneous tumor infarction, the medication was withdrawn for 4 weeks. A second magnetic resonance image disclosed regrowth of the tumor accompanied by rebound of growth hormone and IGF-I secretion. Subsequent biochemical remission has been sustained with preservation of anterior pituitary function since the drug was reinitiated. These findings suggest that intermittent subcutaneous administration of octreotide may provide potent medical ablation of growth hormone-secreting macroadenomas.     

Shrinkage of a primary thyrotropin-secreting pituitary adenoma treated with the long-acting somatostatin analogue octreotide (SMS 201-995)

The long-acting somatostatin agonist octreotide can control TSH hypersecretion from most thyrotropic adenomas. Octreotide therapy has even been shown to improve chiasmal dysfunction. We report another patient in whom octreotide therapy was associated with gradual suppression of TSH hypersecretion, which escaped partially, dramatic and very rapid and sustained improvement of chiasm compression, and dramatic and sustained shrinkage of an unresectable TSH-secreting pituitary tumour. Unusual and prolonged gastrointestinal adverse reactions eventually disappeared except for steatorrhea. In conclusion, octreotide may be considered as first line treatment in patients with unresectable thyrotropic adenomas.     

Abnormal response of luteinizing hormone beta subunit to thyrotrophin-releasing hormone in patients with non-functioning pituitary adenoma

OBJECTIVE it has been suggested that the response of free β-subunit of LH (LHβ) to TRH Is the most useful in-vivo marker of gonadotroph adenomas in patients with non-functioning pituitary adenomas (NFPA). The aim of the present study was to investigate LHβ secretion in patients with NFPA in whom other markers of gonadotroph adenomas, such as supranormal basal concentrations or responses of intact gonadotrophins to TRH, were absent. DESIGN AND PATIENTS Serum basal levels Of LHβ, LH and FSH were evaluated in 80 patients with NFPA showing normal levels of intact gonadotrophin, 20 with PRL-secreting adenomas, 25 with OH-secreting adenomas and 58 healthy subjects. Moreover, LHβ, LH, FSH and alpha-subunit (α-SU) were evaluated in 27 patients with NFPA In whom intact gonadotrophin responses to TRH were absent, 8 with PRL-oma, 7 with GH-oma and 17 healthy subjects before and 20,30 and 60 minutes after the intravenous administration of either 200 μg TRH or placebo. A response was considered present when serum LHβ increased by at least 50% above basal levels. MEASUREMENTS LHβ was evaluated using a new assay based on the sequestration of the combined and free α-SU by an anti α-SU blotinylated monoclonal antibody (MAb) and the subsequent measurement of the LHβ by an IFMA method employing two MAbs directed towards two different epitopes on LHβ. intact LH and FSH were assayed with an IFMA method and α-SU with an IRMA method. RESULTS in basal conditions, no significant difference in the mean values of LHβ was observed among patients with different types of tumour and normal controls. In 9 of 27 (33%) patients with NFPA, TRH caused an abnormal elevation of serum LHβ (net increase 410 ± 403%, range 71-1300) which was completely dissociated from changes in intact gonadotrophins. Of the 5 patients who had a TRH test repeated after transsphenoidal surgery, abnormal LHβ responses disappeared in 2 and were maintained in 3. Disappearance of LHβ response occurred only in patients in whom improvement of visual field and radiological imaging after adenomectomy was observed. in contrast, in ail patients with pituitary tumours other than NFPA and healthy subjects a response to TRH was absent (net increase ranging from 0 to 23%). immunofluorescence, performed on 14 NFPA removed from patients either responsive or unresponsive to TRH, showed a variable proportion of cells positive for LHβ, without a significant difference between the two groups. CONCLUSIONS These results indicate that measurement of basal LHβ is of poor value in the diagnosis of non-functioning pituitary adenomas and the identification of gonadotroph adenomas among non-functioning pituitary adenomas. Conversely, an abnormal response of free LHβ to TRH occurs in about a third of patients with low/normal basal gonadotrophins unresponsive to TRH stimulation.     

Follicle stimulating hormone-secreting pituitary adenoma: inappropriate secretion and effect of pulsatile luteinizing hormone releasing hormone analogue (buserelin) administration.

A patient with an FSH secreting pituitary adenoma is reported. Elevated FSH and serum free alpha-subunit (SU) with low levels of LH and testosterone (T) were found. Immunostaining showed the presence of alpha-SU, FSH-beta and LH-beta subunits. LHRH analogue (buserelin) was administered in a pulsatile manner, by portable computerized infusion pump sc for ten days. During the first 24 h of treatment FSH, LH (p less than 0.001) and T (p less than 0.01) rose significantly. Ten days later, the expected desensitization phenomenon did not occur, but further increases of T (8.4 +/- 2.6, mean +/- SD, vs 17.4 +/- 4.1 nmol/l, p less than 0.001) and FSH (58.9 +/- 9.6 vs 70.7 +/- 3.8 mlU/ml, p less than 0.001) were registered. LH decreased (12.5 +/- 2.4 vs 7.1 +/- 0.6 mlU/ml, p less than 0.001) at day 10, but remained higher than basal level (5.0 +/- 0.6, p less than 0.001). Free alpha-SU also rose (2.8 +/- 0.4 vs 4.4 +/- 1.7 mlU/ml, p less than 0.001) after ten days of treatment. The chronic stimulatory effect of analogue on LH with a lack of desensitization suggests tumorous secretion despite a partially preserved negative feedback of testosterone. Low basal LH levels, in some patients with FSH secreting tumors may not be due to tumor mass effect, but rather may be the consequence of altered LH production and/or secretion by the tumor. Although buserelin may not have a therapeutic effect, it is of use in differential diagnosis of hypergonadotropinemia.     

FSH and LH secreting pituitary adenoma.

A case of FSH and LH secreting pituitary adenoma which was not preceded by hypogonadism is reported. The patient, a 50-year-old man, was admitted to the hospital because of left temporal hemianopsia. No clinical evidence of hypogonadism was demonstrated. Endocrine studies of hypogonadism was demonstrated. Endocrine studies revealed markedly elevated plasma FSH of 295 mIU/ml and slightly elevated LH of 35 mIU/ml (2nd IRP-HMG). Plasma FSH and LH did not respond to the administration of LRF, conjugated equine estrogens and testosterone. Plasma testosterone was 691 ng/dl and rose nromally after pregnant mare's serum gonadotropin. Sperm count was 46 X 10(6)/ml. Transfrontal hypophysectomy was followed by a marked decrease of both FSH (to 19mIU/ml) and LH (to 22 mIU/ml). Histologic examination of the tumor revealed 90% chromophobe cells and 10% slightly eosinophilic cells. Two sizes of secretory granules were demonstrated. Tumor cells in tissue culture secreted both FSH and LH.     

Serum concentrations of gonadotrophins in hypergonadotrophic patients following stimulation by a long-acting analogue of luteinizing hormone-releasing hormone

The effect of D-Ser(TBU)6-EA10-LRH, a long-acting analogue of luteinizing hormone-releasing hormone (LRH), was studied in patients with hypergonadotrophism due to orchidectomy (n = 8) or due to Klinefelter's syndrome (n = 6). Patients orchidectomized less than 7 days prior to the administration of the compound presented with maximum concentrations of LH (63.8 +/- 29.9 mIU/ml) within 60 min following iv injection of the LRH-analogue (10 micrograms). This behaviour of LH was qualitatively similar to that seen in healthy men. In patients orchidectomized more than 40 days prior to the administration of the LRH-analogue and in patients with Klinefelter's syndrome the occurrence of maximum serum LH-concentrations (115.0 +/- 39.4 and 149.4 +/- 134.5 mIU/ml, respectively) was delayed up to 240-360 min following iv LRH-analogue. This pattern of LH secretion is similar to that of healthy women. No qualitative differences in stimulated FSH-concentrations were observed between the described groups of hypergonadotrophic patients. These findings demonstrate a time-dependent increase in the 'second pool' of LH following orchidectomy. The similar behaviour of stimulated LH-release in healthy women and in male patients with long-term hypergonadotrophic hypogonadism could indicate an augmented production of endogenous LRH in these individuals as compared to healthy men, providing an explanation for the sexually related differences in the LH-response upon the administration of the LRH-analogue.     

The effect of thyroid hormone and a long-acting somatostatin analogue on TtT-97 murine thyrotropic tumors.

Thyroid hormone inhibits thyrotropin (TSH) production and thyrotrope growth. Somatostatin has been implicated as a synergistic factor in the inhibition of thyrotrope function. We have previously shown that pharmacological doses of thyroid hormone (levothyroxine [LT4]) inhibit growth of murine TtT-97 thyrotropic tumors in association with upregulation of somatostatin receptor type 5 (sst5) mRNA and somatostatin receptor binding. In the current study, we examined the effect of physiological thyroid hormone replacement alone or in combination with the long-acting somatostatin analogue, Sandostatin LAR, on thyrotropic tumor growth, thyrotropin growth factor-beta (TSH-beta), and sst5 mRNA expression, as well as somatostatin receptor binding sites. Physiological LT4 replacement therapy resulted in tumor shrinkage in association with increased sst5 mRNA levels, reduced TSH-beta mRNA levels and enhanced somatostatin receptor binding. Sandostatin LAR alone had no effect on any parameter measured. However, Sandostatin LAR combined with LT4 synergistically inhibited TSH-beta mRNA production and reduced final tumor weights to a greater degree. In this paradigm, Sandostatin LAR required a euthyroid status to alter thyrotrope parameters. These data suggest an important interaction between the somatostatinergic system and thyroid hormone in the regulation of thyrotrope cell structure and function.     

Reduction of pituitary size by the somatostatin analogue SMS 201-995 in a patient with an islet cell tumour secreting growth hormone releasing factor

Acromegaly is rarely caused by the ectopic secretion of growth hormone releasing factor (GRF) from peripheral neuroendocrine tumours. We evaluated the ability of a recently developed somatostatin analogue (SMS 201-995, Sandoz) to reduce hormone levels and pituitary size in a young woman with acromegaly and Zollinger-Ellison syndrome secondary to a metastatic pancreatic islet cell tumour secreting GRF and gastrin. Gastrin, GRF, and growth hormone (GH) levels declined dramatically following the initiation of therapy with the analogue by continuous iv infusion. Although intermittent sc therapy was not effective in suppressing hormone levels, continuous sc infusion of SMS 201-995 has provided good control of both GRF and GH levels for nine months. Moreover, treatment with SMS 201-995 was associated with a substantial reduction in pituitary enlargement and an improvement in her gastric symptoms. Continuous sc infusion of SMS 201-995 may be useful in treating enlarged pituitaries resistant to other modes of therapy.     

Effects of chronic treatment with oestrogen, an oestrogen antagonist and a potent luteinizing hormone releasing hormone agonist analogue on pituitary responsiveness to luteinizing hormone releasing hormone in the rat

The rise in gonadotrophin release which occurs after ovariectomy is caused by steroid withdrawal resulting in an enhanced pituitary responsiveness to LH releasing hormone (LHRH) associated with increased LHRH release and pituitary LHRH binding. The effects of oestrogen replacement after ovariectomy and chronic treatment of intact rats with an oestrogen antagonist, tamoxifen, on LH release and in-vitro pituitary responses to LHRH have been investigated. Capsules containing crystalline oestradiol, implanted at the time of ovariectomy, completely inhibited the rise in LH release although pituitary responsiveness was greater after 10 days in the oestrogen-treated rats than in untreated ovariectomized controls. On day 4 after ovariectomy pituitary responses to LHRH were comparable in both treated and untreated groups although in both groups the responses were greater than those measured in intact dioestrous rats. Treatment with tamoxifen over a 4-day period also augmented pituitary responsiveness but only at the lowest dose (0.5 mg/kg); no effect on serum LH concentrations was observed. Higher doses of the antagonist (1 and 2 mg/kg) did not affect pituitary responses, although the highest dose did cause a significant rise in serum LH. Treatment with a daily dose of 50 ng [D-Ser(But)6]LHRH(1-9)nonapeptide-ethylamide, starting on the day of ovariectomy, markedly attenuated the LH responses to LHRH ex vivo at days 2, 4 and 10 after ovariectomy. In contrast, the analogue treatment did not abolish the rise in LH release but this was proportionately less than in controls.     

Gonadotropin-release upon intravenous administration of a long-acting analogue of luteinizing hormone-releasing hormone in females with increased plasma-androgens.

D-Ser-(TBU)3-EA10-LH-RH, an analogue of luteinizing hormone-releasing hormone (LH-RH) with prolonged action evokes in normal male and female subjects a qualitatively different secretory pattern of LH, as peak levels are reached between 30 and 60 min in males and between 120 and 240 min in females. Females with increased production of adrenal androgens due to congenital adrenal hyperplasia (off substitution therapy; N=8), idiopathic hirsutism (N=1) and adrenocortical carcinoma (N=2) present upon the administration of the LH-RH-analogue with a secretory pattern of LH and FSH which is qualitatively identical with that of normal female subjects, whereas the response of LH in these patients differs from that seen in normal males. Pre-treatment with dexamethasone did not induce any qualitative changes in the secretory response of LH and FSH upon the LH-RH-analogue in patients with increased endogenous production of adrenal androgens. A larger pool and/or a more pronounced de novosynthesis of LH, which apparently is not altered by increased levels of adrenal andorgens, may be the cause of the more pronounced and prolonged increase of LH in female subjects following the administration of the LH-RH-analogue.     

Prolactin suppresses luteinizing hormone secretion and pituitary responsiveness to luteinizing hormone-releasing hormone by a direct action at the anterior pituitary

In pathological or experimental hyperprolactinemia, the elevated circulating levels of PRL are the usual cause of the impairment in gonadotropic function. The present study was undertaken to determine whether PRL could suppress basal LH secretion and LHRH-stimulated LH release by a direct action at the anterior pituitary. Anterior pituitaries from ovariectomized rats were incubated in medium 199 alone or in medium 199 containing ovine PRL, and basal and the LHRH-stimulated LH release were followed for 2 or 3 h in vitro. Ovine PRL at 40 and 80 micrograms/ml suppressed basal LH release by 41% and 72%, respectively, at 2 h of incubation. This suppressive effect of both concentrations of PRL continued to the third hour of incubation. LHRH at 5 ng/ml increased the release of LH from pituitaries incubated in medium alone by 57%, 61%, and 107% at 1, 2, and 3 h of incubation, respectively. However, in the pituitaries treated with 40 micrograms/ml ovine PRL, the stimulatory effects of LHRH were diminished at all time points measured. Pretreatment of anterior pituitaries with ovine PRL for 6 h significantly inhibited by 81% the LHRH (5 ng/ml) stimulation of LH release at 2 h of incubation. On the other hand, inhibition of endogenous PRL release by 10(-6) M bromocriptine enhanced the stimulatory effects of 5 ng/ml LHRH by 2.5-fold at 2 h of incubation. The inhibitory effects of PRL on basal and stimulated LH secretion appeared unique, since neither BSA nor vasopressin could elicit similar suppressive effects on LH. These results suggest that in anterior pituitaries exposed to elevated levels of PRL, LH secretion and pituitary responsiveness to LHRH could be impaired. This phenomenon may contribute in part to the antigonadotropic effects of PRL.     

Long-term treatment with bromocriptine of a plurihormonal pituitary adenoma secreting thyrotropin, growth hormone and prolactin.

A 48-year-old female presented with acromegaly, amenorrhea and hyperthyroidism associated with high serum free T4 levels and measurable TSH concentrations. The administration of GHRH induced significant increases in GH, PRL and TSH. Conversely, intravenous infusion of dopamine or oral administration of bromocriptine effectively inhibited GH, PRL and TSH secretion. Serum alpha-subunit levels were neither affected by GHRH, dopamine nor bromocriptine. Transsphenoidal surgery was performed and immunostaining of the tissue showed that the adenoma cells were positive for GH, PRL or TSH. The patient was treated with bromocriptine at a daily oral dose of 10 mg after surgery. Serum TSH were initially suppressed but returned within reference intervals with persistent normalized free T4 levels. Serum PRL became undetectable and GH levels were stable around 6 ng/ml except the periods of poor drug compliance, when serum TSH, GH and PRL levels rose considerably. The patient was followed-up for 10 years without any change in the residual adenoma tissues as detected by magnetic resonance imaging. These findings suggest that long-term bromocriptine therapy is effective in treating the hypersecretory state of a plurihormonal adenoma secreting TSH, GH and PRL.     

Haemodynamic effects of a long-acting somatostatin analogue in patients with liver cirrhosis

The influence of SMS 201-995 (octreotide, Sandostatin), a long-acting somatostatin analogue, on splanchnic haemodynamics was studied in 15 patients with liver cirrhosis and in 5 healthy individuals before, during, and after 60 min of intravenous SMS infusion (25 and 50 micrograms/h, respectively). No adverse effects of the SMS infusion were seen. In the basal state the estimated hepatic blood flow was 1.04 +/- 0.08 l/min (mean +/- SE) in the patients and 1.62 +/- 0.09 l/min (P less than 0.001) in the controls. At 15 min after the beginning of the infusion the blood flow had already decreased by 15-30% (P less than 0.05-0.01). The reduction was more marked in controls than in patients, and it persisted in both groups during and for 60 min after the infusion. Wedged hepatic venous pressure, measured in the patients, was 20 +/- 2 mmHg in the basal state and 18 +/- 1 mmHg during the infusion (P less than 0.05), and it remained at this level for 60 min after the infusion. Free hepatic venous pressure was unchanged throughout the study. Splanchnic oxygen uptake was similar in the two groups in the basal state and remained unaltered during and after SMS infusion. Both heart rate and arterial systolic and diastolic blood pressure remained unchanged during SMS administration. In summary, SMS infusion results in a fall in hepatic blood flow and a slight but significant decrease in wedged hepatic venous pressure, whereas no effect was noted on the systemic circulation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Hypersecretion of an abnormal form of follicle-stimulating hormone associated with suppressed luteinizing hormone secretion in a woman with a pituitary adenoma

Pituitary tumors producing FSH have hitherto been reported only in males, all of whom have had normal or raised LH levels in serum. This report describes a female with a pituitary adenoma associated with supranormal serum levels of FSH. The FSH was also qualitatively abnormal when compared with FSH in the serum of other postmenopausal women, had a lower apparent molecular weight on gel chromatography, and was less negatively charged, as shown by electrophoresis. The results of LRH tests and suppression tests with ethinyl estradiol indicated autonomy of the FSH-producing adenoma. The FSH level increased concomitant with tumor enlargement and decreased after surgical removal of the pituitary adenoma or pituitary irradiation. The serum level of the glycoprotein alpha-subunit was raised about 100-fold. Any free FSH beta-subunits were not detectable in serum. The abnormal FSH had antigenic sites in common with both the alpha- and beta-subunits of FSH. The LH level was extremely low, and there was no response to LRH tests or ethinyl estradiol treatment. After gel chromatography, a small amount of LH, corresponding to 1/50th of the average for the patient's age, was detected at the position for normal LH. There was no GH response to insulin-induced hypoglycemia, while the cortisol increase was normal. Thyroid and adrenal functions were normal. The PRL level was within the normal range and increased slightly after estrogen treatment.     

Hyperthyroidism secondary to a pituitary adenoma secreting TSH, FSH, alpha-subunit and GH

A 51-year-old man had been treated for hyperthyroidism with antithyroid drugs for 8 years. He was then found to have a large pituitary adenoma with biochemical evidence of overproduction of TSH, FSH and alpha-subunit. Subsequent immunocytochemical and tissue culture studies confirmed secretion of these hormones. In addition, the tumour stained for GH and was capable of GH production in vitro. This combination of hormones produced by a pituitary adenoma has not been previously reported.     

Association between KISS1 rs5780218 promoter polymorphism and onset of growth hormone secreting pituitary adenoma

Objectives

This study analyzed the KISS1 c.-145delA (rs5780218) promoter polymorphism in a cohort of patients with growth hormone secreting pituitary adenoma (somatotropinoma) and controls, to investigate its role in the incidence of acromegaly and to assess patient/tumor characteristics.Material and methods rs5780218 allelic and genotypic distributions were compared between 49 somatotropinoma patients and 167 healthy controls. rs5780218 was also assessed in relation to patient characteristics and tumor aggressiveness, as characterized by tumor invasion and resistance to conventional therapy. The relationship between KISS1 mRNA expression and the rs5780218 genotype was also assessed in available pituitary tumor samples.

The long-acting somatostatin analogue SMS 201-995 causes malabsorption

Somatostatin and its long-acting analogue SMS 201-995 (Sandostatin) have been suspected of causing steatorrhoea. The aim of this study was to examine the effect of SMS 201-995 on fat assimilation in healthy subjects, using 14C-triolein and 3H-oleic acid as tracers of dietary triglycerides and free fatty acids, respectively, and 51CrCl3 as non-absorbable marker. Six healthy male volunteers participated in the double-blinded, randomized, crossover study. In each test period either 1 ml of SMS 201-995, containing 200 micrograms, or 1 ml of isotone saline was given subcutaneously three times within 16 h. Faeces were collected for 3 days, every stool separately. The faecal 14C-triolein and 3H-oleic acid excretion was calculated from two aliquots of faeces. In addition, the mean daily faecal fat excretion was estimated. When placebo was given, the median 14C-triolein excretion was 1% (range, 0.9-1.6%), the median 3H-oleic acid excretion was 5% (range, 3-10%), and the daily faecal fat excretion was 4 g/day (range, 1-6 g/day), all within normal limits. When SMS 201-995 was given, the faecal 14C-triolein excretion increased to a median of 75% (range, 43-119%), the 3H-oleic acid excretion increased to a median of 82% (range, 46-126%), and the faecal fat excretion increased to a median of 22 g/day (range, 4-34 g/day), all clearly above normal. The faecal 14C-triolein/3H-oleic acid test showed triglycerides and free fatty acids to be equally malassimilated, which indicates malabsorption.