Insulin acromegaly

Insulin is a powerful anabolic hormone but it is unlikely that insulin deficiency causes skeletal muscle atrophy by direct action on muscle fibers (as opposed to neurogenic atrophy) except in chronic untreated cases. There is however a close parallel between the catabolic states induced by glucocorticoid excess and by insulin deficiency. Moreover, impaired insulin action is implicated in other endocrine myopathies as a contributory cause of muscle wasting. Both acromegaly and thyrotoxicosis are associated with insulin resistance due to a postreceptor defect, and secondary hyperparathyroidism due to hypophosphatemia also gives rise to insulin insensitivity. 

Prolonged exposure to elevated growth hormone and insulin-like growth factor I levels can lead to serious complications in patients with acromegaly. Aggressively manage... 

It is a peptide containing 14 amino acids and inhibits the release of growth hormone, TSH and prolactin from the pituitary and insulin and glucagon in pancreas. It has a very short plasma half-life. Because of its shorter duration of action and lack of specificity in inhibiting only GH secretion, its use in the treatment of acromegaly is limited. 

In 24 patients with acromegaly, glucose homeostasis was assessed before and after 6 months of either 2-weekly lanreotide (n = 14) or monthly octreotide (n = 10) (21). Insulin resistance and triglyceride concentrations improved. Glucose homeostasis, measured by HbAic, deteriorated. This was probably due to impaired insulin secretion. There were no distinct differences between the analogues, but the numbers were small. 

Parkinson, C., Kassem, M., Heickendorff, L., et al. PEGvisomant-induced serum insulin-like growth factor-I normalization in patients with acromegaly returns elevated markers of bone turnover to normal. J. Clin. Endocrinol. Metab. 88(12) 5650-5655. 2003. 

Endocrinopathies Excessive production of insulin counterregulatory hormones can cause diabetes mellitus. Examples include excessive production of growth hormone (acromegaly), cortisol (Cushing s syndrome), epinephrine (pheochromocytoma), and glucagon (glucago-noma). 

Type 1 DM idiopathic is a nonimmune form of diabetes frequently seen in minorities with intermittent insulin requirements. The prevalence of type 1 DM has been increasing over the last one hundred years. Maturity onset diabetes of youth (MODY), which has an identifiable genetic defect in the glucokinase gene, and endocrine disorders such as acromegaly and Cushing s syndrome, can be secondary causes of DM. These unusual etiologies, however, only account for 1% to 2% of the total cases of type 2 DM. See the section on other forms of diabetes mellitus later in this chapter for further discussion. 

Pharmacologic therapy for acromegaly should be considered when surgery and irradiation are contraindicated, when rapid control of symptoms is needed, or when other treatments have failed to normalize growth hormone (GH) and insulin-like growth factor-1 (IGF-I) concentrations. 

R7. Rieu, M., Girard, F., Bricaire, H., and Binoux, M., The importance of insulin-like growth fiu tor (somatomedin) measurements in the diagnosis and surveillance of acromegaly. /. CUn. Endocrinol. Metab. 55, 147-153 (1982). 

Octreotide acetate is an endocrine and metabolic agent, whose actions mimic those of natural hormone somatostatin. It suppresses secretion of serotonin and gastroentero-pancreatic peptides (e.g., gastrin, insulin, glucagon, secretin, and motilin), and also suppresses the growth hormone. It is indicated in the symptomatic treatment of diarrhea associated with carcinoid tumors, treatment of profuse watery diarrhea associated with vasoactive intestinal peptide tumors (VIPoma), and to reduce blood levels of growth hormone and IGF-1 in acromegaly patients who have had inadequate response to or cannot be treated with resection, pituitary irradiation, and bromocriptine at maximally tolerated doses. 

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