Faculty Bibliography

Severe long-term complaints of dumping occur in a small number of patients after gastric surgery. Dietary modification, fiber preparations, and medical therapy are often ineffective. In these severely affected patients administration of the somatostatin analog octreotide before meals appears to be a promising new strategy. The effects of octreotide on both gastrointestinal transit time and hormonal changes appear to contribute to the benefits seen in dumping syndrome. However, as the majority of studies conducted have employed only a single dose of octreotide, careful long-term assessment of the nutritional and metabolic effects will be required. Recent results suggest that octreotide may be administered up to 2 hr before a meal and therefore has a sufficiently long duration of action to be of practical long-term use. Moreover, general improvements in life-style, as well as beneficial effects on symptoms, have been reported with long-term treatment, although the potential development of diarrhea will require careful monitoring. The development of an oral or nasal formulation should further improve the practical application of octreotide as a treatment for dumping syndrome.

This article reports the changes in gallbladder function examined by ultrasonography in 20 Chinese patients with active acromegaly treated with sc injection of the somatostatin analog octreotide in dosages of 300-1500 micrograms/day for a mean of 24.2 +/- 13.9 months. During treatment with octreotide, 17 patients developed sludge, 10 had gallstones, and 1 developed acute cholecystitis requiring surgery. In all of 7 patients examined acutely, gallbladder contractility was inhibited after a single 100-micrograms injection. In 8 patients followed for 24 weeks, gallbladder contractility remained depressed throughout therapy. After withdrawal of octreotide in 10 patients without gallstones, 8 patients assessed had return of normal gallbladder contractility within 1 month. In 8 of the remaining 10 patients who developed gallstones during treatment, gallbladder contractility normalized in 5 patients (3 of whom has disappearance of their stones within 3 weeks), and remained depressed in 3 (2 of whom had stones present at 6 months). Our results suggest that the suppression of gallbladder contractility is the cause of the successive formation of bile sludge, gallstones, and cholecystitis during octreotide therapy in Chinese acromegalic patients. It is therefore very important to follow the changes of gallbladder function during long-term octreotide therapy of acromegalic patients.

Somatostatin analogues such as octreotide have been shown in experimental systems to exhibit antineoplastic activity. Further laboratory and clinical research is needed to clarify the mechanism of action of somatostatin analogues as antineoplastics, and to determine if the encouraging preclinical results will lead to novel endocrine approaches to the treatment of breast cancer.

Twenty-five acromegalic patients were studied during 6 years of treatment with octreotide, with a particular focus on the following parameters: (1) Administration schedule: in 10 patients, continuous subcutaneous (SC) octreotide infusion was compared with injections of octreotide at three dose levels (100, 250, and 1,500 micrograms/24 h) and was found to induce a greater and less-fluctuating 24-hour growth hormone (GH) suppression. (2) Carbohydrate tolerance: average 24-hour blood glucose levels were unaffected by octreotide, regardless of administration schedule. Oral carbohydrate tolerance and intravenous (IV) glucose tolerance were unaffected by continuous octreotide infusion. However, octreotide injection given shortly before the tests reduced carbohydrate tolerance. (3) Thyroid function: octreotide and somatostatin acutely reduce the response of thyroid-stimulating hormone (TSH) to thyrotropin-releasing hormone (TRH). After a few days of treatment, it was demonstrated that octreotide slightly inhibits iodothyronine deiodination and induces a transient reduction in serum triiodothyronine (T3), rapidly compensated for by a persistent slight elevation of serum TSH. (4) Fat absorption was estimated as 24-hour fecal fat content and found to be in the same high-normal range before and after octreotide treatment. Vitamin K and D absorption were unaffected by octreotide. The incidence of gallstone formation was not greater than in the general Danish population, possibly due to the schedule used for octreotide injections. (5) Foot volume was regularly estimated and found to decrease with time, on average by 12% during the first 18 months.(ABSTRACT TRUNCATED AT 250 WORDS)

The aim of this study was to determine the role of octreotide administration in acromegalic patients as a preparation for selective adenomectomy using transsphenoidal route. Octreotide was administered for 3 to 6 weeks before surgery in 12 patients and for 4 to 39 months in 25 patients. The clinical response was judged as excellent or good in 10 of 12 patients from group I and in 23 of 25 patients from group II. Marked reduction (ie, greater than 50% of initial values) in serum growth hormone (GH) levels was seen in all patients, with levels to less than 5 micrograms/L in 68% of patients and less than 2 micrograms/L in 27%. Insulin-like growth factor 1 (IGF-1) levels decreased to within normal limits in half the cases. During long-term treatment, an escape phenomenon could be seen. Varying degrees of tumor shrinkage were seen in more than 50% of cases. During surgery, with regard to the relative ease or difficulty in removing the tumor, the consistency of the tumor and the separation of normal from pathological tissue, no significant difference was observed between patients given octreotide and those from control series. Morphological changes in adenomatous tissue were rather small. The surgical outcome was similar in the pretreated series as in the control series, except in enclosed adenomas, which showed a tendency to a higher success rate. Since octreotide improves both the clinical condition and hormonal parameters and induces varying degrees of tumor shrinkage, it is potentially useful as an adjunct to surgery. Morphological data suggest that octreotide exercises a functional inhibitory effect on GH release.

Diabetes is characterized by paradoxical hypersomatotropinemia and hyperglucagonemia. The latter appears to enhance the tendency in imperfect metabolic control to reduce nitrogen balance, and the former appears to accelerate the deterioration of carbohydrate and lipid metabolism, and also to induce peripheral insulin resistance and hyperinsulinemia. In addition to direct metabolic effects, increasing evidence points to an association between hypersomatotropinemia and a number of metabolically dependent, characteristic functional abnormalities linked to the development of late diabetic manifestations. These include increased capillary fragility, lipid and hemostatic aberrations, tissue hyperperfusion, including increased cardiac output and renal plasma flow, and kidney hypertrophy. In theory, octreotide's actions could reduce these aberrations, and, in fact, this has been confirmed in recent experimental trials.

This report details the first half of a double-blind, crossover sequence (Latin square) study of local and hormonal effects of nasally insufflated Sandostatin compared with those of subcutaneously injected Sandostatin. Nine of the planned 16 patients have been studied. They received a single application of 0.5, 1.0, and 2.0 mg Sandostatin as nasal powder and 0.1 mg by subcutaneous (SC) injection. The results indicate that absorption from the nasal epithelium occurs after approximately 10 minutes and comprises approximately 20% of the dose administered. This indicates that peak serum Sandostatin values occur very rapidly, ie, 10 minutes after application. After approximately 2 hours, the serum disappearance rates are similar to those obtained after SC injection. The suppressive effect on serum growth hormone (GH) levels is equal with the two forms of application and suggests that future clinical treatment with an intranasal application of 0.5 mg thrice daily is feasible. No side effects were noted apart from an immediate swelling of nasal mucosa, which receded gradually over the following 2 hours. This was either unnoticed or considered insignificant by the patients and will probably be deemed harmless by the rhinologist in eventual long-term clinical trials.