0021-972X/90/7104-1059$02.00/0 Journal of Clinical Endocrinology and Metabolism Copyright © 1990 by The Endocrine Society
Vol. 71, No. 4 Printed in U.S.A.
Secretory Dynamics of Growth Hormone in an Acromegalic Patient Associated with Graves' Disease* AKIRA SHIMATSU, HIROYUKI MURABE, SHIGEKAZU SASAKI, NAOKI HATTORI, TSUTOMU TANOH, AND HIROO IMURA Second Division, Department of Internal Medicine, Kyoto University Faculty of Medicine, Kyoto 606, Japan
ABSTRACT. The dynamics of GH secretion were investigated in an acromegalic patient with Graves' disease during treatment with antithyroid drugs and radioactive iodine. The mean (±SE) basal plasma GH levels were 16.5 ± 0.9 and 7.8 ± 0.7 ^g/L during the hyperthyroid and euthyroid states, respectively. There was a positive correlation (r = 0.902) between basal GH and free T4 levels. Twenty-four-hour plasma GH and urinary GH excretion both increased during the thyrotoxic state. Intra-
T
HYROID hormones have an essential role in the synthesis and secretion of GH. The release of GH in response to provocative stimuli is blunted in hypothyroidism (1, 2). However, the regulation of GH secretion in hyperthyroidism has not been fully elucidated; a normal response to insulin-induced hypoglycemia or arginine infusion has been reported (2-4), while decreased secretion has been observed by other investigators (5-7). We studied a patient with acromegaly associated with hyperthyroidism and describe a close correlation between thyroid function and GH secretion.
venous administration of TRH induced a marked increase in plasma GH levels during euthyroidism and a modest increase when the paient was hyperthyroid, whereas GH release induced by GH-releasing hormone was not altered by thyroid status. These findings suggest that hyperthyroidism stimulated spontaneous GH secretion from the pituitary adenoma, but inhibited the stimulating effect of TRH. (J Clin Endocrinol Metab 7 1 : 1059-1063, 1990)
and TSH binding inhibitory immunoglobulin was +34.0% (normal, —10 to +10%). Magnetic resonance imaging of the brain revealed a localized low intensity area in the pituitary gland, suggesting the presence of a microadenoma. The patient was treated with antithyroid drugs, with poor control of thyroid function. Ten millicuries of 131I were administered, and he became transiently hypothyroid. After resuming a euthyroid state with T4 supplementation, the patient underwent successful transsphenoidal adenomectomy. Histological examination of the adenoma tissues showed positive immunostaining for GH. He remained euthyroid after T4 was discontinued. Hyperhidrosis disappeared, and the thickness of the soft tissues was decreased after pituitary surgery.
Case Report A 30-yr-old man was hospitalized because of palpitations and acral enlargement. Physical examination revealed signs of hyperthyroidism, including a diffusely enlarged thyroid gland. He also had clinical features of acromegaly, such as excessive sweating, increased thickness of the soft tissues, and protrusion of the brows and mandible. Plasma levels of GH and insulinlike growth factor-I (IGF-I) were 19.5 ^g/L and 2.26 X 103 U/ L, respectively, with an increased basal metabolic rate (+66%). Hyperthyroidism was confirmed by elevated serum levels of T4) T3, and free T4 (f T4) and suppressed TSH levels. Antithyroidalmicrosomal antibody was positive at 1:6400 (normal,
Vol. 71, No. 4 Printed in U.S.A.
Secretory Dynamics of Growth Hormone in an Acromegalic Patient Associated with Graves' Disease* AKIRA SHIMATSU, HIROYUKI MURABE, SHIGEKAZU SASAKI, NAOKI HATTORI, TSUTOMU TANOH, AND HIROO IMURA Second Division, Department of Internal Medicine, Kyoto University Faculty of Medicine, Kyoto 606, Japan
ABSTRACT. The dynamics of GH secretion were investigated in an acromegalic patient with Graves' disease during treatment with antithyroid drugs and radioactive iodine. The mean (±SE) basal plasma GH levels were 16.5 ± 0.9 and 7.8 ± 0.7 ^g/L during the hyperthyroid and euthyroid states, respectively. There was a positive correlation (r = 0.902) between basal GH and free T4 levels. Twenty-four-hour plasma GH and urinary GH excretion both increased during the thyrotoxic state. Intra-
T
HYROID hormones have an essential role in the synthesis and secretion of GH. The release of GH in response to provocative stimuli is blunted in hypothyroidism (1, 2). However, the regulation of GH secretion in hyperthyroidism has not been fully elucidated; a normal response to insulin-induced hypoglycemia or arginine infusion has been reported (2-4), while decreased secretion has been observed by other investigators (5-7). We studied a patient with acromegaly associated with hyperthyroidism and describe a close correlation between thyroid function and GH secretion.
venous administration of TRH induced a marked increase in plasma GH levels during euthyroidism and a modest increase when the paient was hyperthyroid, whereas GH release induced by GH-releasing hormone was not altered by thyroid status. These findings suggest that hyperthyroidism stimulated spontaneous GH secretion from the pituitary adenoma, but inhibited the stimulating effect of TRH. (J Clin Endocrinol Metab 7 1 : 1059-1063, 1990)
and TSH binding inhibitory immunoglobulin was +34.0% (normal, —10 to +10%). Magnetic resonance imaging of the brain revealed a localized low intensity area in the pituitary gland, suggesting the presence of a microadenoma. The patient was treated with antithyroid drugs, with poor control of thyroid function. Ten millicuries of 131I were administered, and he became transiently hypothyroid. After resuming a euthyroid state with T4 supplementation, the patient underwent successful transsphenoidal adenomectomy. Histological examination of the adenoma tissues showed positive immunostaining for GH. He remained euthyroid after T4 was discontinued. Hyperhidrosis disappeared, and the thickness of the soft tissues was decreased after pituitary surgery.
Case Report A 30-yr-old man was hospitalized because of palpitations and acral enlargement. Physical examination revealed signs of hyperthyroidism, including a diffusely enlarged thyroid gland. He also had clinical features of acromegaly, such as excessive sweating, increased thickness of the soft tissues, and protrusion of the brows and mandible. Plasma levels of GH and insulinlike growth factor-I (IGF-I) were 19.5 ^g/L and 2.26 X 103 U/ L, respectively, with an increased basal metabolic rate (+66%). Hyperthyroidism was confirmed by elevated serum levels of T4) T3, and free T4 (f T4) and suppressed TSH levels. Antithyroidalmicrosomal antibody was positive at 1:6400 (normal,
