Cardiovascular effects of the somatostatin analog octreotide in acromegaly
Article Abstract:
Acromegaly is a disease predominantly afflicting middle-aged individuals in which a tumor of the pituitary gland causes enlargement of the bones of the extremities and head, swelling of the soft tissues of the face, and severe metabolic abnormalities. Cardiovascular disease is also common. It has been reported that administration of a brain peptide, somatostatin, improves cardiovascular function in patients with acromegaly. However, the short plasma half-life of somatostatin limits its therapeutic utility. The development of the long-acting somatostatin analog octreotide holds promise for the treatment of acromegaly. Seven patients with active acromegaly, based on clinical tests (failure to suppress growth hormone secretion following oral ingestion of glucose), who were referred to an endocrinological clinic for treatment, were studied. Three of the patients had congestive heart failure (a condition caused by a decreased ability of the heart to pump blood, characterized by weakness, shortness of breath, abdominal pain, and swelling in the lower body); the other four patients had no cardiovascular symptoms. Patients received subcutaneous injections of octreotide three times daily for three months; following clinical evaluation, they continued to receive injections for up to two years. Blood chemistry evaluations indicated that the octreotide acted as a somatostatin analog (e.g. growth hormone and insulin-like growth factor levels were suppressed), and blood volume was reduced in all patients. The patients without heart disease symptoms showed minor cardiovascular responses to octreotide. In the three patients with congestive heart failure, a dramatic return to normal was seen in several indices of cardiovascular function, and this normalization was maintained for the duration of the treatment. However, it is not known if these effects are a direct result of reduced growth hormone levels, or an indirect response to some other change such as a reduction in blood volume. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: Annals of Internal Medicine
Subject: Health
ISSN: 0003-4819
Year: 1990
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Sleep apnea in acromegaly
Article Abstract:
Acromegaly is a disease that results from oversecretion of growth hormone, often from microscopic tumors of the pituitary gland. Growth hormone is necessary for normal childhood growth, and causes the bones to lengthen, among other effects. Since most bones can not grow once a person has reached adulthood, the excess growth hormone of acromegaly can only cause some bones to enlarge. This results in increases in the size of the hands, feet, skull, and jaw, giving an unusual appearance to affected individuals. One of the concurrent problems some persons with acromegaly develop is sleep apnea, or periods of not breathing during sleep. This is caused by intermittent obstruction of the upper airways by the enlarged tissues of the throat, producing a lack of oxygen, disturbed sleep, nightmares and daytime sleepiness. A group of 53 persons with known acromegaly were referred to a sleep study center, where they were monitored for breathing abnormalities and growth hormone levels while they slept. Of these, 43 met specific diagnostic criteria for sleep apnea. No relation was found between growth hormone levels and the presence or absence of sleep apnea. Twenty-two of the patients with sleep apnea also had high blood pressure, a known consequence of sleep apnea for many patients. Conservative estimates, based on these results, suggest that sleep apnea occurs in up to 17 percent of persons with acromegaly, compared with 1 to 5 percent of the general population. Many patients with acromegaly and sleep apnea also develop high blood pressure, which might explain the higher than average risk of heart disease among persons with acromegaly. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: Annals of Internal Medicine
Subject: Health
ISSN: 0003-4819
Year: 1991
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