The alpha-adrenoceptor control of adrenocorticotropin secretion in man.

Oral administration to six normal male volunteers of an alpha-adrenoceptor agonist, guanfacine (4 mg daily for 4 days) had no significant effect on ACTH release induced by metyrapone (a single oral 1-g dose). The same treatment with guanifacine significantly reduced ACTH secretion stimulated by insulin-induced hypoglycemia in another group of six male volunteers. These results indicate that, in man, the adrenergic system has an inhibitory input on stress-induced ACTY secretion via alpha-adrenoceptors. The concept of alpha-adrenergic control of ACTH secretion in man is in agreement with some experimental in vivo and in vitro data recorded in animals.

Inhibitory effect of guanfacine, a central alpha-adrenoceptor agonist, on prolactin secretion stimulated by insulin-induced hypoglycemia.

In six normal male volunteers oral administration of an alpha-receptor agonist, guanfacine (1 mg/q.i.d. for 4 days), had no effect on PRL release induced by 5 mg metoclopramide iv. The same treatment with quanfacine in six other normal subjects significantly reduced PRL secretion stimulated by insulin-induced hypoglycemia (P less than 0.05). These results suggest that an adrenergic pathway, hypothalamic or extrahypothalamic, might be involved in the inhibitory control of PRL secretion.

Effect of 1-5 hydroxytryptophan infusion on growth hormone and prolactin secretion in man.

The effect of a new soluble ester of 1-5 hydroxytryptophan (1-5 HTP, Ro 3-5940, 200 mg infusion) on prolactin (PRL) and growth hormone (GH) release was tested in 11 young, healthy subjects (6 men, 5 women). To minimize side-effects, peripheral decarboxylase inhibition was achieved with benserazide (Ro 4-4602.) PRL increased significantly (P less than 0.01) after benserazide alone in all subjects. A further significant increase (P less than 0.01) of PRL plasma levels occurred only in women up to 90 min after the infusion of 1-5 HTP was discontinued. Benserazide administration had no effect of basal GH levels, but a significant increase of GH release (P less than 0.01) was noticed 30-120 min after the end of 1-5 HTP infusion in both men and women. The mean peak value of GH plasma levels after 1-5 HTP administration was 32.0 +/- 8.8 ng/ml. It was postulated that benserazide penetrated at the level of the pituitary, decreasing the synthesis of dopamine and consequently reducing its known inhibitory effect on PRL release. The PRL increase (statistically significant only in women), as well as the release of GH after 1-5 HTP infusion, was considered as further evidence for stimulatory serotoninergic control of both PRL and GH secretion.

Sandostatin LAR in acromegalic patients: a dose-range study.

Sandostatin LAR is a sustained release formulation of octreotide that has been developed by microencapsulating the drug with biodegradable poly(lactide-glycolide)-glucose. We have investigated the efficacy and tolerability of Sandostatin LAR given as a single dose im to patients with active acromegaly who showed good GH suppression during a 2- to 4-week pretreatment period with octreotide given sc. Two double blind studies were performed. Initially, 14 patients were randomized and observed over 42 days after a single im injection of 3, 6, 9, or 12 mg Sandostatin LAR. In the second study, 15 patients were randomized and observed over 60 days after a single im injection of either 20 or 30 mg Sandostatin LAR. Assessments of 12-h GH and octreotide profiles and adverse events were made on day -14 (during treatment with Sandostatin, sc); day 0 (off treatment after wash-out period); days 1, 7, 14, 21, 28, 35, and 42; and, for study 2, also on days 49 and 60 after the im injection. Only injections of 20 or 30 mg were followed by a suppression of basal GH and insulin-like growth factor I to levels comparable to those seen during sc treatment. The suppression of mean GH to less than 5 micrograms/L lasted for 4 weeks in the group receiving 20 mg and for at least 6 weeks in those given 30 mg Sandostatin LAR. The pharmacokinetic profile fitted a biphasic drug release model previously described for peptides in similar drug delivery systems. Serum concentrations correlated with the im administered dose. Suppression of GH and insulin-like growth factor I was achieved at serum octreotide concentrations exceeding approximately 600 ng/L. Tolerability was good. Sandostatin LAR holds promise as a valuable drug for the treatment of acromegaly. The results of ongoing long term studies will provide further necessary knowledge of the drug.

Long-lasting suppression of prolactin secretion and rapid shrinkage of prolactinomas after a long-acting, injectable form of bromocriptine.

Since Corenblum reported in 1975 the first documented reduction of tumor size in two patients with macroprolactinoma, evidence has accumulated that bromocriptine causes shrinkage of PRL-secreting adenomas in most patients. Recently a long-acting form of bromocriptine (bromocriptine LA) was developed. A single dose of 50 mg i.m. decreases basal and sleep-related PRL secretion in normal subjects for 28 days. We treated 13 patients (8 women, 5 men) with PRL secreting tumors (5 macroadenomas and 8 microadenomas) with a single dose (50 mg) of bromocriptine LA. In the 5 patients with macroprolactinomas plasma PRL levels decreased markedly within 12 hours, reaching normal levels in only one patient. In all patients the suppression of PRL secretion lasted at least 28 days and the tumor size was reduced by 20% to 59% within 21 days after the injection. Visual fields improved in all 3 patients with abnormal vision prior to the injection. In one patient with bitemporal hemianopsia an almost normalization of the visual field was noted 24 hours after bromocriptine LA administration. In 7/8 patients with microprolactinomas plasma PRL levels decreased to within the normal range within 12 hours after the administration of bromocriptine LA. The normalization of PRL secretion lasted for at least 28 days. Menses resumed in all 6 women 7 to 41 days after the injection, galactorrhea disappeared in all 4 patients, and libido and potency become normal in both men with microprolactinomas. Patients treated with bromocriptine LA reported only short-lasting (1 hour - 2 days) mild or moderate adverse effects, consisting of dizziness (4 patients) and nausea (4 patients). Long-acting bromocriptine should be considered as the initial management for patients with PRL-secreting tumors. The use of bromocriptine LA could also overcome the compliance problems that occur in many patients soon after the initiation of oral bromocriptine therapy.

Long term therapy of patients with macroprolactinoma using repeatable injectable bromocriptine.

The efficacy and tolerability of a long term treatment (21-53 months; mean, 36) with a new injectable form of bromocriptine (Parlodel LAR, Sandoz) was assessed in 13 patients (9 males and 4 females, aged 14-68 yr) with macroprolactinoma. Parlodel LAR was administered deeply im once monthly, with 50 mg as the first dose. Depending on the patient's tolerability to the drug and the PRL levels, the dose was individually progressively increased to 100 mg (2 patients), 150 mg (3 patients), or 250 mg (4 patients). Persistently normal PRL levels were recorded in 4 patients even after the first injection and in 5 other patients treated with higher doses of Parlodel LAR (2 patients with 100 mg/month; 3 patients with 150 mg/month). The remaining 4 patients who were treated with 250 mg/month had a marked reduction of PRL levels (72-94%), but did not reach normalization. Two patients treated with 150 mg/month maintained normoprolactinemia in spite of subsequent dose reduction of Parlodel LAR to 50-100 mg/month. In 1 patient PRL plasma concentrations remained within normal range for 3 months after the transitory discontinuation of Parlodel LAR at the end of the first year of therapy. Regular menses were resumed in 1 of 3, and galactorrhea disappeared in 2 of 3 women. All male patients had a return of libido and potency; gynecomastia disappeared in both male patients, and galactorrhea disappeared in 1 of 2 male patients. Visual fields improved in all 5 patients; complete normalization occurred in 2 of them. A consistent shrinkage of the macroadenoma (23-100%) at different times after therapy was shown by magnetic resonance imaging and/or computed tomography in 12 of 13 patients. Six patients reported mild/moderate side-effects (nausea, vomiting, orthostatic hypotension, or dizziness) within 24 h after the first injection. In 2 of these patients, mild side-effects persisted for 1-2 days after the first 3-6 injections, and in one patient, mild nausea was reported after each injection. In conclusion, in patients with macroprolactinoma, Parlodel LAR is an effective and well tolerated preparation of bromocriptine when administered once a month.

Depot long-acting somatostatin analog (Sandostatin-LAR) is an effective treatment for acromegaly.

Octreotide (Sandostatin) is a synthetic analog of somatostatin, an endogenous GH inhibitory peptide that has been used as an adjunct to surgery and radiotherapy in the treatment of acromegaly. When given sc in divided daily doses, it lowers serum GH to less than 5 micrograms/L in approximately 50% of cases. Data suggest that continuous infusions of somatostatin analogs may be more effective in lowering GH. We have evaluated Sandostatin-LAR, a new long-acting preparation of Sandostatin, in eight patients with acromegaly. After an initial pharmacokinetic study, patients received a minimum of 10 im injections of Sandostatin-LAR (20, 30, or 40 mg) at 28- or 42-day intervals. Serum GH levels decreased from 10.7 +/- 2.8 micrograms/L (mean +/- SE) at baseline to a nadir of 2.6 +/- 0.4 micrograms/L after the tenth injection, and to less than 5 micrograms/L in every patient. Serum insulin-like growth factor-I decreased from 927 +/- 108 ng/mL at baseline to 472 +/- 59 ng/mL at the end of the sixth injection and returned to normal (< 500 ng/mL) in seven of the eight patients. This was associated with significant improvements in headache, arthralgia, and sweating. There was no evidence of octreotide accumulation, and the drug was well tolerated. To date, no gallstones have occurred, and serial pituitary imaging has revealed no increase in the size of the initial pituitary tumor. In particular, two previously untreated patients have shown complete regression of the initial microadenoma and have serum GH values of less than 2.5 micrograms/L. Sandostatin-LAR is an effective and well-tolerated treatment for patients with acromegaly. Undoubtedly the initial indication for Sandostatin-LAR will be in the patient who is not cured after surgery and radiotherapy, but our experience suggests that it may be used as a primary treatment in some acromegalics.

Sandostatin LAR in acromegalic patients: long-term treatment.

We have evaluated the long term effects and safety of Sandostatin LAR, a long acting formulation of octreotide, during 18 subsequent injections given every fourth week to 14 octreotide-sensitive acromegalic patients. The dosages (20, 30, or 40 mg) were adjusted according to GH response, side-effects, or symptom relief and assessed on day 28 after each injection. We found a stable and consistent suppression of GH and insulin-like growth factor (IGF-I) during the entire study period. Daily mean GH levels were suppressed below 2 micrograms/L in 9, to between 2-5 micrograms/L in 3, and to between 5-10 micrograms/L in 2 patients. The corresponding IGF-I values were suppressed to below 500 micrograms/L in 9 patients and to between 500-1000 micrograms/L in the remaining 5 patients. Increasing the dosage of Sandostatin LAR from 20 to 30 mg had no obvious additional effect on GH suppression, but provided a further decrease in IGF-I levels. Forty milligrams of the drug had no additional effect on GH or IGF-I compared to 30 mg. Acromegalic signs and symptoms improved during treatment. Although the fluctuations of daily mean octreotide levels were high, dosage increments caused an increase in the average serum concentration in the individual patient. Pituitary tumor size reduction was seen in all previously untreated patients (n = 4). We found only minor changes in glucose metabolism (oral glucose tolerance test and hemoglobin A1C) during treatment, but no biologically relevant changes in thyroid function (TSH, T3, and free T4). One patient developed asymptomatic gallstones, and another acquired vitamin B12 deficiency during treatment. The drug is well tolerated during long term treatment. Sandostatin LAR may well be the future medical treatment of choice for acromegalic patients.

Long-term effects of depot long-acting somatostatin analog octreotide on hormone levels and tumor mass in acromegaly.

The effects of a 12- to 24-month treatment with depot long-acting octreotide (OCT-LAR) on hormone profile, tumor mass, and clinical symptoms were reported in 36 patients with active acromegaly [GH, 34.2 +/- 5.6 microg/L; insulin-like growth factor I (IGF-I), 784.5 +/- 40.4 microg/L]. Fifteen patients were de novo whereas 21 had previously undergone unsuccessful surgery. Serum GH (P < 0.0001) and IGF-I levels (P < 0.0001) significantly decreased as early as after the first injection of OCT-LAR and progressively declined during the 12-24 months of treatment both in de novo and in operated patients. At the last follow-up, GH hypersecretion was controlled (< or =2.5 microg/L) in 69.4% whereas normal IGF-I levels were achieved in 61.1% of patients. GH and IGF-I suppression during OCT-LAR treatment was similar in de novo and operated patients as shown by nadir GH (2.3 +/- 0.6 vs. 2.2 +/- 0.6 microg/L) and IGF-I (323.1 +/- 34.9 vs. 275.5 +/- 33.0 microg/L), percent suppression of GH (92.7 +/- 2.0 vs. 85.9 +/- 3.3%) and IGF-I (57.4 +/- 4.9 vs. 61.5 +/- 4.6%), and prevalence of GH (73.3 vs. 76.2%) and IGF-I (53.3 vs. 71.4%) control. A decrease in tumor volume was observed in 12 of 15 de novo patients, whereas no shrinkage was detected in 4 of 9 operated patients. No patient had tumor reexpansion during OCT-LAR treatment. Significant clinical improvement was obtained in all patients; heart rate, systolic blood pressure, and diastolic blood pressure significantly decreased in the entire population. A mild but significant increase of blood glucose levels, followed by a decrease of serum insulin levels, was observed after 3 months of treatment: this effect subsided with treatment continuation. OCT-LAR treatment was well tolerated by most patients. In conclusion, long-term treatment with OCT-LAR was effective in controlling GH and IGF-I hypersecretion in most patients with acromegaly, when applied either as primary therapy or as adjunctive therapy after surgery. Tumor shrinkage was observed in de novo patients during OCT-LAR treatment, suggesting that it can be successfully applied as primary therapy in patients bearing invasive tumors, who are less likely to be cured after surgery.

Hormonal mechanism of milk secretion in the newborn.

The mechanism inducing milk secretion in 10 puerperal women and in their children (Witch's milk) was studied by means of sequential hormone measurements starting at delivery and continued during the first postpartum week. Determinations included prolactin (PRL), growth hormone (GH), estradiol 17beta (E217beta), and progesterone (PG). Hormonal levels in the newborns closely paralleled those of the mothers. In both groups, the onset of milk secretion coincided with the disappearance of sex steroids from plasma in the presence of elevated PRL concentrations. Response to TRH (8 microng/kg) revealed adequate PRL reserve, and failure of this peptide to modify basal GH in the neonates was suggestive of appropriate hypothalamic control. The role of estrogens in the induction of pituitary hyperplasia during pregnancy is discussed.

Treatment of macroprolactinomas with the long-acting and repeatable form of bromocriptine: a report on 29 cases.

Twenty-nine patients with macroprolactinomas were treated by monthly intramuscular injections of the long-acting and repeatable form of bromocriptine (Parlodel-LAR) in doses ranging from 50-150 mg. They were divided into two groups: group I consisted of 22 patients who received Parlodel LAR before transsphenoidal adenomectomy; group II was composed of 7 patients with earlier neurosurgery and of 2 patients from group I not cured by transsphenoidal adenomectomy. Duration of therapy varied from 1-12 months, and a total of 104 injections was given. At nadir day, serum PRL levels were situated between less than 1% and 43% of pretreatment values. At day 28 after the first injection, serum PRL levels varied between less than 1% to 139% of initial values. No difference could be detected between the two groups regarding the percent of PRL inhibition. Long-term treatment with Parlodel-LAR resulted in a sustained inhibition of PRL secretion, except for 1 case. Resumption of menstrual cycles occurred in 4 out of 15 women and correction of hypogonadism in 4 out of 14 men. Amelioration of disturbed visual fields was recorded in 3 out of 8 patients. Diminution of the adenoma volume was radiologically documented in 14 out of 22 cases. Only few and mild side effects were recorded. One patient with partial adrenal deficiency suffered from a syncope, but this was prevented by hydrocortisone supplementation during the subsequent Parlodel-LAR administration. In conclusion, Parlodel-LAR proved effective in the treatment of macroprolactinomas, achieving rapid inhibition of PRL secretion, and in some patients amelioration of hypopituitarism, reduction in tumor size, and improvement in visual fields, and caused no serious side effects. It is a valuable preparation to surgery and can also be used in long-term medical therapy.

Cardiovascular effects of depot long-acting somatostatin analog Sandostatin LAR in acromegaly.

Cardiovascular disease is the most severe complication of acromegaly accounting for the increased mortality of these patients. Recently, the slow-release form of octreotide (OCT; Sandostatin LAR, OCT-LAR), for im injection every 28 days, was reported to induce suppression of GH levels below 7.5 mU/L (2.5 microg/L) in 39-75% of patients, and normalization of insulin-like growth factor (IGF)-I levels for age in 64-88% of patients, with an excellent patients' compliance. The aim of the present study was to investigate the early effect of OCT-LAR treatment on the left ventricular (LV) structure and performance in 15 somatostatin analog-naive patients with acromegaly (GH, 94.8 +/- 24.9 mU/L; IGF-I, 757.9 +/- 66.6 microg/L), focusing on the early effect of GH and IGF-I suppression on the heart. Cardiac structure was investigated by echocardiography, whereas LV performance was investigated by gated-blood-pool scintigraphy, before and after 3 and 6 months of treatment with OCT-LAR. OCT-LAR was initially administered im, at a dose of 20 mg every 28 days, for 3 months. In six patients, the dose was then increased to 30 mg every 28 days to achieve disease control, which was considered when fasting and/or glucose-suppressed GH values were below 7.5 and 3.0 mU/L, respectively, together with IGF-I values within the normal range for age. The treatment with OCT-LAR for 6 months induced a significant decrease of GH (to 12.9 +/- 3.0 mU/L) and IGF-I levels (to 340.3 +/- 40.2 microg/L) in all 15 patients. After 6 months of treatment, the percent IGF-I suppression was 52.8 +/- 4.4%, and serum GH/IGF-I levels were normalized in 9 patients. A significant decrease of LV mass index (LVMi), interventricular septum thickness, and LV posterior wall thickness was observed in all 15 patients after 3 and 6 months of OCT-LAR treatment: LVMi was decreased by 19.1 +/- 2.0% without any difference in patients with (19.9 +/- 2.7%) or without disease control (17.8 +/- 3.3%). Among the 11 patients with LV hypertrophy, 6 normalized their LVMi after treatment. At study entry, an inadequate LV ejection fraction (LVEF) at rest (<50%) was found in 5 patients (33.3%), whereas an impaired response of LVEF at peak exercise (<5% increase of basal value) was found in 9 patients (60%). A significant increase in LVEF, both at rest (from 51.6 +/- 2.6 to 58.1 +/- 1.7%, P < 0.01) and at peak exercise (from 51.6 +/- 2.3 to 60.2 +/- 2.4%, P < 0.001) was found in patients with (as compared with those without) disease control (from 55.2 +/- 3.8 to 58.0 +/- 4% and from 61.8 +/- 4.6 to 61.8 +/- 3.4%, respectively). Among the 5 patients with inadequate LVEF at rest, all but 1 regained a normal LVEF after 6 months of treatment; whereas, among the 9 patients with an impaired response of the LVEF at peak exercise, 3 patients normalized, 4 improved, and 2 impaired their responses after treatment. The percent of IGF-I suppression was significantly correlated with the percent increase of resting LVEF (r = 0.644, P < 0.01). Exercise duration (from 6.0 +/- 0.7 to 7.3 +/- 0.7 min) and capacity (from 69.0 +/- 8.2 to 80 +/- 7.8 watts) were increased in the 15 patients considered as a whole, but the improvement in the exercise response was significant only in patients with disease control (P < 0.01 and P < 0.05, respectively) who also had an increase in the peak ejection rate (P = 0.03). No change in hemodynamic parameters, either at rest or at peak exercise, was found after treatment with OCT-LAR in the 15 patients. In conclusion, the results of the present study demonstrate that OCT-LAR im injections every 28 days induces a sustained suppression of GH levels and IGF-I levels in all acromegalic patients, allowing achievement of disease control in 60% of patients after 6 months of treatment. The sustained suppression of IGF-I levels was followed by a significant reduction of LVMi in all patients already after 3 months of treatment, with recovery of LV hypertrophy in 6 of 11 patients. (ABSTRACT TRUN

A pregnancy in an acromegalic woman during bromocriptine treatment: effects on growth hormone and prolactin in the maternal, fetal, and amniotic compartments.

An unexpected 20-week-old pregnancy was found in a young acromegalic who had been treated with 10 mg bromocriptine/day for 10 months. The drug was continued throughout the period of gestation. No growth of the pituitary adenoma was noticed. The intrauterine development of the fetus was normal. Bromocriptine therapy had no discernible effect on the expected patterns of secretion of placental hormones, but inhibited completely the increase of PRL in the serum of the mother. Maternal plasma GH concentrations were very high in spite of the treatment and progressively declined after delivery. The plasma GH level was normal in the child, but PRL was very low at birth and increased in the following days. The expected high PRL concentration was found in the amniotic fluid. This case study suggests that bromocriptine crosses the human placenta and affects the fetal pituitary, maternal GH does not influence fetal or amniotic GH, and amniotic fluid PRL correlates poorly with either maternal or fetal blood levels and is not affected by bromocriptine.

Occurrence and effects of octreotide antibodies during nasal, subcutaneous and slow release intramuscular treatment.

OBJECTIVE: Previous studies have indicated that antibody formation against octreotide is extremely rare. We examined the occurrence of octreotide antibody formation after treatment with three administration forms in large populations of patients with acromegaly or carcinoid syndrome. DESIGN: (i) Nasally administered octreotide: 70 previously untreated patients and 81 previously s.c. octreotide-treated patients participated. (ii) Subcutaneously administered octreotide: 172 acromegalic patients and 59 patients with carcinoid syndrome treated for up to 12 years participated. (iii) Intramuscularly administered depot octreotide (Sandostatin LAR): 62 acromegalic patients participated. METHODS: Presence of antibodies is defined as increased precipitation by polyethylene glycol of (125)I-octreotide after incubation with serum; this was also used for screening of cross-reaction with somatostatin and lanreotide (Somatuline). RESULTS: In patients who received nasal octreotide for at least 9 and up to 12 months (n=42), the occurrence of octreotide antibodies was 77% and 81% for previously untreated and treated patients respectively. In subcutaneously treated patients it was 63/231 (27%) after a mean exposure of 3 years. In patients treated for more than 5 years (n=53) it was 57% and after 8 years (n=18) 72%. In contrast, no patient could with certainty be identified to be antibody-positive after a mean of 2.5 years intramuscular Sandostatin LAR treatment (n=47). In all populations, the antibody-positive patients were as well controlled as the antibody-negative patients. Octreotide antibodies did not cross-react with native somatostatin (n=141), while about 25% of the antibody-positive sera did cross-react with the somatostatin analogue, lanreotide (Somatuline, Ipstyl, Angiopeptin). CONCLUSIONS: Antibody formation against octreotide is much more frequent than previously believed. It depends primarily on drug exposure time and route of administration. It does not alter the GH/IGF-I status in treated acromegalic patients and induces only mild local reactions in some patients.

New evidence for growth hormone modulation by the alpha-adrenergic system in man.

The effect of BS 100-141, N-amidino 2-(2.6 dichlorophenyl) acetamide hydrochloride, a new drug with central alpha-adrenoceptor activity, on growth hormone (GH) secretion was investigated in 24 young, healthy volunteers. Six normal volunteers were treated with 1 mg and 8 with 2 mg BS 100-141; 8 of these 14 were treated with placebo, using single oral doses. Ten normal volunteers received single oral doses of 2 and 4 mg BS 100-141, 0.15 and 0.30 mg clonidine in a randomized, crossover study. GH secretion was significantly increased after 2 and 4 mg BS 100-141 and 0.30 mg clonidine. Prolactin and insulin plasma levels, glycerol, and blood sugar were not significantly influenced by BS 100-141. The results give new evidence for an alpha-adrenoceptor mechanism modulating GH secretion in normal young men.

Sandostatin LAR (microencapsulated octreotide acetate) in acromegaly: pharmacokinetic and pharmacodynamic relationships.

Double-blind, single-dose studies of 120 acromegalic patients given 10, 20, and 30 mg Sandostatin LAR (Sandoz Pharma Ltd, Basel, Switzerland) established the drug's pharmacokinetic profile. Patients then entered open-labeled extension phases, with Sandostatin LAR intramuscular (IM) injections every 4 weeks. These produced broadly constant octreotide concentrations with dose proportionality. Area fluctuations were minimal. Steady-state conditions were generally reached after the second to third injection. There was no evidence of downregulation with Sandostatin LAR over 1 year of study. Based on the pharmacokinetic/pharmacodynamic relationship of octreotide, a starting dose of 20 mg Sandostatin LAR and administrations every 4 weeks provide growth hormone (GH) control comparable to the thrice-daily subcutaneous (SC) injection regimen, which is commonly 0.3 to 0.6 mg/d. The reduction from the burden of two to three SC injections per day is a particular advantage of Sandostatin LAR, which is an attractive alternative to the approved Sandostatin injection.

Sandostatin LAR: a promising therapeutic tool in the management of acromegalic patients.

A stable and sustained suppression of growth hormone (GH) secretion was noted in 101 patients treated long term with individual doses (20 and 30 mg in 89 patients, 40 mg in 12 patients) of Sandostatin LAR (Sandoz Pharma Ltd, Basel, Switzerland). Doses of 20 mg and 30 mg at 4-week intervals delivered average octreotide concentrations of 1,348 +/- 483 ng/L and 2,631 +/- 1,026 ng/L, respectively, in steady-state conditions and provided adequate control of patients who had been well controlled during treatment with 0.1 mg and 0.2 mg thrice-daily subcutaneous (SC) Sandostatin. Suppression of GH serum concentrations to less than 5 micrograms, 2 micrograms, and even 1 microgram/L was recorded in more patients and more consistently during long-term treatment with Sandostatin LAR than Sandostatin. A marked decrease or even a normalization of insulin-like growth factor-1 (IGF-1) serum concentrations was observed after the first double-blind 10-, 20-, or 30-mg dose of Sandostatin LAR. A progressive improvement was recorded during long-term treatment, with normalization of IGF-1 serum concentrations in 65.3% of patients. A marked clinical improvement was observed in parallel, with 36 of 101 patients (35.6%) becoming asymptomatic after the nineteenth injection of Sandostatin LAR. A greater than 20% shrinkage of the GH-secreting adenoma was also recorded in 12 of 14 patients treated with Sandostatin LAR after receiving only 2 to 4 weeks of treatment with SC Sandostatin and in 11 of 18 patients receiving Sandostatin LAR as adjuvant therapy after failure of surgery. The systemic tolerability of Sandostatin LAR was good, and most adverse events were mild and short term (1 to 2 days). No impairment of thyroid function was detected. Newly occurring gallstones were recorded in four of 101 patients and microlithiasis in four of 101 after up to 30 months of treatment with Sandostatin LAR. Due to its excellent efficacy, good tolerability, convenience of administration, and acceptability by patients, Sandostatin LAR is considered a promising therapeutic tool in the management of acromegalic patients.

Return of gonadotropic function in postpartum women during bromocriptine treatment.

The rapid postpartum return of gonadotropic function during bromocriptine treatment was investigated through hormonal measurements in 15 women. Luteinizing hormone (LH) was measured by a novel and specific assay that does not cross-react with human chorionic gonadotropin (hCG). Prolactin was effectively suppressed by bromocriptine and hCG was cleared within 2 weeks. During the first week, both follicle-stimulating hormone (FSH) and LH were undetectable. The return of FSH and LH secretion occurred in the second postpartum week and initially was characterized by a high FSH/LH ratio. The causes of the 1-week delay in resumption of pituitary gonadotropin secretion are not known, but endogenous opioids may play a role. The possible relation between the high FSH/LH ratio and low LH pulse frequency also is discussed.

Long-acting injectable bromocriptine (Parlodel LAR) in the chronic treatment of prolactin-secreting macroadenomas.

OBJECTIVE: To evaluate the efficacy and tolerability of Parlodel LAR (Sandoz, Basel, Switzerland), a long-acting injectable bromocriptine, in PRL-secreting macroadenomas. DESIGN: Eleven patients with macroprolactinomas were studied in an academic environment in an open and prospective protocol. Ten patients were followed for 6 months and 8 for 1 year. Fifty to 200 mg IM of Parlodel LAR were administered every 28 days. RESULTS: At the end of the 1st month, 64% of the patients had PRL suppression of > 75% of baseline values. After 1 year, 88% of the cases had PRL suppression of > 90%. Persistent PRL normalization was seen in three cases. Tumor shrinkage was seen in 64% of the patients on day 5, in 73% on day 28, and in 90% after 6 months of treatment. Early visual field improvement was seen in 83% of the cases. All patients had improvement of clinical symptoms. CONCLUSION: Parlodel LAR is well tolerated and very effective in the long-term treatment of patients with PRL-secreting macroadenomas.

A long-acting repeatable form of bromocriptine as long-term treatment of prolactin-secreting macroadenomas: a multicenter study.

OBJECTIVE: To assess the efficacy and tolerability of monthly injections of the long-acting repeatable bromocriptine in patients with macroprolactinomas. DESIGN: Open and prospective trial. SETTING: This multicenter trial was carried out in seven university hospitals. PATIENTS: Forty-two patients with prolactin (PRL)-secreting macroadenomas. INTERVENTIONS: Fifty to 200 mg of the drug were administered intragluteally every 28 days for 6 to 24 months. MAIN OUTCOME MEASURES: The efficacy was assessed by repetitive plasma PRL measurements, visual field determinations, and computed tomography scan examinations. RESULTS: After the first 50-mg injection, the mean percentage decrease of PRL levels was 71% from baseline on day 14; between days 1 and 28, PRL levels were suppressed to normal in nine cases, and a clear tumor shrinkage was documented in 21% of the patients. Normalization of PRL secretion was obtained in 62%, and a clear-cut reduction in tumor size in 50% of the patients after 6 months of treatment. CONCLUSIONS: The long-acting repeatable form of bromocriptine was a well tolerated and quickly effective treatment in most of these patients with macroprolactinomas.