Central Hypothyroidism Related to Pituitary Adenomas: Low Incidence of Central Hypothyroidism in Patients With Acromegaly

Abstract

Context The most frequent cause of central hypothyroidism (CeH) is pituitary adenomas, but the mechanisms remain unclear. Objective We investigated serum thyroid levels and GH/IGF-1 in central hypothyroidism in untreated patients with pituitary nonfunctioning and GH-secreting adenomas. Design This was a retrospective cross-sectional study of cases collected from Gunma University and Toranomon Hospitals between 2007 and 2016. Patients One-hundred thirty-nine cases of nonfunctioning pituitary adenoma (NFPA) and 150 cases of GH-secreting pituitary adenoma (GHPA) were analyzed. Main Outcome Measures The correlations between thyroid levels, several clinicopathological parameters, and GH/IGF-1 were examined. Results Twenty-four percent of NFPA patients had CeH. The severity did not correlate with tumor size, age, or sex, and all cases had normal TSH levels. In contrast, only 8.7% of GHPA patients had CeH; approximately half had normal TSH levels and approximately half had low TSH levels. Serum TSH levels in GHPA patients were significantly lower and free T4 (FT4) and free T3 levels were higher than those in patients with NFPA. Furthermore, approximately one-fourth of GHPA patients had normal FT4 and low TSH levels. In addition, serum FT4 levels and serum TSH levels were positively and negatively correlated, respectively, with serum IGF-1 levels. Furthermore, IGF-1 levels in patients with GHPA decreased with age. Conclusions (i) NFPA patients with CeH had TSH levels within a normal range. (ii) GHPA patients had a low incidence of CeH, which may be a result of stimulated thyroid function by GH/IGF-1. (iii) We found an age-dependent decrease in serum IGF-1 levels in patients with GHPA.

Hyperprolactinemia and Hypopituitarism in Acromegaly and Effect of Pituitary Surgery: Long-Term Follow-up on 529 Patients

“…A recent study showed that the incidence of central hypothyroidism was 8.7% among acromegaly patients, far lower than that in NFPA patients, which might result from the stimulation effect of GH/IGF-1 on thyroid function ( 9 ). Our data revealed that 5.9% of acromegaly patients had hypothyroidism, and the IGF-1 levels in these patients were remarkably lower than those with normal thyroid function.…”

“…The adenoma can cause acromegalic manifestations by producing excessive GH, hyperprolactinemia by secreting prolactin or compressing the pituitary stalk, and hypopituitarism in at least one axis by damaging the pituitary gland ( 4 – 6 ). Hypopituitarism in acromegaly mainly includes central hypogonadism, central hypothyroidism, and central adrenal insufficiency ( 1 , 2 , 7 – 9 ). Therefore, apart from the influence of excessive GH and IGF-1, acromegaly patients also suffer from hyperprolactinemia and hypopituitarism, causing comorbidities and worsening their quality of life and prognosis ( 7 , 9 – 11 ).…”

“…Hypopituitarism in acromegaly mainly includes central hypogonadism, central hypothyroidism, and central adrenal insufficiency ( 1 , 2 , 7 – 9 ). Therefore, apart from the influence of excessive GH and IGF-1, acromegaly patients also suffer from hyperprolactinemia and hypopituitarism, causing comorbidities and worsening their quality of life and prognosis ( 7 , 9 – 11 ).…”

“…Unfortunately, due to the rarity of the disease, information regarding the rates and clinical correlations of hyperprolactinemia and hypopituitarism in acromegaly and the effect of surgery is limited. Previous studies were usually retrospective, enrolled small sample size, or focused only on a single axis ( 9 , 21 , 25 , 26 ). The Pituitary Surgery Center of Neurosurgery Department at Peking Union Medical College Hospital (PUMCH) is one of the largest in China performing 800-1000 pituitary surgeries per year ( 27 ).…”

The intestinal flora of patients with GHPA affects the growth and the expression of PD-L1 of tumor

“…Growth hormone-secreting pituitary adenoma (GHPA) is a common subtype of FPA [ 2 ]. Excess production of GH leads to acromegaly, heart disease, sleep apnea, and other conditions that shorten life expectancy [ 3 ]. After systemic treatment (surgery and medication), certain GHPAs challenge effective clinical treatment because of relapse or drug resistance [ 4 , 5 ].…”