Diagnosis of hypoprolactinemia.

Prolactin is a polypeptide hormone composed of 199 amino acids, synthesized by lactotroph cells. Its primary effects are on the mammary gland and gonadal axes, but it also influences different organs and systems, particularly metabolic functions. Current literature has mainly focused on the diagnosis, monitoring, and treatment of hyperprolactinemia. Due to the lack of a well-established effective treatment for hypoprolactinemia, it is not clinically emphasized. Therefore, data on its diagnosis is limited. Hypoprolactinemia has been associated with metabolic dysfunctions such as type 2 diabetes mellitus, fatty liver, dyslipidemia, fertility problems, sexual dysfunction, and increased cardiovascular disease. While often seen as a part of combined hormone deficiencies due to pituitary damage, isolated prolactin deficiency is rare. Hypoprolactinemia can serve as a marker for extensive pituitary gland damage and dysfunction.Low or undetectable serum prolactin levels and the absence of a sufficient prolactin peak in the thyrotropin-releasing hormone (TRH) stimulation test are considered diagnostic for hypoprolactinemia. Gender appears to influence both basal prolactin levels and TRH stimulation test responses. Basal prolactin levels of, at least, 5 ng/mL for males and 7 ng/mL for females can be used as cut-off levels for normal prolactin reserve. Minimum peak prolactin responses of 18 ng/mL for males and 41 ng/mL for females to TRH stimulation can exclude hypoprolactinemia. However, larger population studies across different age groups and sexes are needed to better define normal basal prolactin levels and prolactin responses to the TRH stimulation test.

The diagnosis and prevalence of hypoprolactinemia in patients with panhypopituitarism and the effects on depression and sexual functions.

PURPOSE: We aimed to investigate the prevalence and the diagnostic criteria of hypoprolactinemia in patients with panhypopituitarism and the effects of hypoprolactinemia on depression and sexual functions. MATERIALS AND METHODS: Forty-eight patients with panhypopituitarism and 20 healthy volunteers were included. Basal hormone levels were measured and a TRH stimulation test was performed. For the evaluation of sexual functions, questionnaries of Female Sexual Functional Index (FSFI) for females and International Erectile Functional Index for males were performed to the subjects. Depressive symptoms were evaluated by Beck Depression Envontory score (BDI-II). RESULTS: The peak PRL response to TRH stimulation test at 5th percentile in the control group was 18.6 ng/ml in males and 41.6 ng/ml in females and accepted as the cut-offs for sufficient response of PRL. Prolactin was insufficient in 42(87.5%) patients. A basal PRL level of ≤ 5.7 ng/ml in males and 7.11 ng/ml in females was 100% specific in predicting an inadequate response to TRH stimulation test with 80% and 70% sensitivity respectively. A basal PRL level of ≥ 8.5 ng/dl in males was 100% specific and 76% sensitive, and in females a level of ≥ 15.2 ng/dl was 96% specific and 66% sensitive in predicting an adequate response to TRH. PRL deficient patients with panhypopituitarism had higher depression scores compared to the controls, lower sexual function scores in males. CONCLUSION: PRL deficiency is prevalent among individuals with panhypopituitarism, with the potential to result in elevated depression scores in both sexes and impaired sexual functions in males. A basal PRL level seems to be sufficient for the diagnosis of hypoprolactinemia in routine clinical practice.

Cutaneous findings in patients with acromegaly and its relationship with concomitant endocrinopathies.

OBJECTIVES: Skin changes in acromegaly are often the first sign of the disease. The aim of this study was to describe the cutaneous findings in patients with acromegaly. In addition, a secondary aim was to investigate the possible association of these findings with remission status and concomitant endocrinopathies. DESIGN, PATIENTS, AND MEASUREMENTS: In this prospective multicenter study, 278 patients over the age of 18 years with acromegaly who were followed up in 14 different tertiary healthcare institutions were included. These patients, who were followed up by the Endocrinology Department, were then referred to a dermatologist for dermatological examination. The frequency of skin lesions was investigated by detailed dermatologic examination. Dermatological diagnosis is reached by clinical, dermatological and/or dermoscopic examination, and rarely skin punch biopsy examinations in suspicious cases. The possible association of the skin findings between remitted and nonremitted patients and with concomitant endocrinopathies were evaluated. RESULTS: The most common skin findings in patients with acromegaly in our study were skin tags (52.5%), cherry angiomas (47.4%), seborrhoea (37%), varicose veins (33%), acneiform lesions (28.8%), hyperhidrosis (26.9%) and hypertrichosis (18.3%). Hypertrichosis was significantly more prevalent in patients nonremitted (p: .001), while xerosis cutis was significantly more prevalent in patients remitted (p: .001). The frequency of diabetes mellitus and hypothyroidism was significantly higher in patients with varicose veins and seborrhoeic keratosis than those without. Additionally, the coexistence of hypothyroidism, hyperthyroidism and galactorrhea was significantly higher in patients with Cherry angioma than in those without Cherry angioma (p-values: .024, .034 and .027, respectively). The frequency of hypogonadism in those with xerosis cutis was significantly higher than in those without (p: .035). CONCLUSIONS: Cutaneous androgenization findings such as skin tag, seborrhoea, acne and acanthosis nigricans are common in patients with acromegaly. Clinicians should be aware that skin findings associated with insulin resistance may develop in these patients. It can be said that the remission state in acromegaly has no curative effect on cutaneous findings. Only patients in remission were less likely to have hypertrichosis. This may allow earlier review of the follow-up and treatment of acromegaly patients presenting with complaints of hypertrichosis. Additionally, it can be said that patients with skin findings such as cherry angioma may be predisposed to a second endocrinopathy, especially hypothyroidism. Including dermatology in a multidisciplinary perspective in acromegaly patient management would be beneficial to detect cutaneous findings earlier.

Disease-free survival and the prognostic factors affecting disease-free survival in patients with medullary thyroid carcinoma: a multicenter cohort study.

PURPOSE: Despite several factors that may have been associated with poor disease-free survival (DFS) in patients with medullary thyroid carcinoma (MTC), only a few studies have evaluated the prognostic factors affecting DFS in MTC patients. Therefore, this study evaluated the prognostic factors affecting DFS, in a large number of patients with MTC. METHODS: Patients treated for MTC were retrospectively analyzed. Patients were stratified as having persistent/recurrent disease and no evidence of disease (NOD) at the last follow-up. The factors affecting DFS after the initial therapy and during the follow-up period were investigated. RESULTS: This study comprised 257 patients [females 160 (62.3%), hereditary disease 48 (18.7%), with a mean follow-up time of 66.8 ± 48.5 months]. Persistent/recurrent disease and NOD were observed in 131 (51%) and 126 (49%) patients, respectively. In multivariate analysis, age > 55 (HR: 1.65, p = 0.033), distant metastasis (HR: 2.41, p = 0.035), CTN doubling time (HR: 2.7, p = 0.031), and stage III vs. stage II disease (HR 3.02, p = 0.048) were independent predictors of persistent/recurrent disease. Although 9 (8%) patients with an excellent response after the initial therapy experienced a structural recurrence, the absence of an excellent response was the strongest predictor of persistent/recurrent disease (HR: 5.74, p < 0.001). CONCLUSIONS: The absence of an excellent response after initial therapy is the strongest predictor of a worse DFS. However, a significant proportion of patients who achieve an excellent response could experience a structural recurrence. Therefore, careful follow-up of patients, including those achieving an excellent response is essential.

Evaluation of growth hormone deficiency in women with unexplained infertility.

PURPOSE: Growth hormone (GH) has been recognized to play a regulatory role in female reproduction. It has been reported that infertile GH deficient patients regained fertility after GH replacement. The frequency of GH deficiency is not established in patients diagnosed with unexplained infertility. Here, we aim to present the prevalence of GH deficieny in this patient group. METHODS: We included patients diagnosed with unexplained infertility throughout 18 months. Insulin tolerance test (ITT) and glucagon stimulation tests (GST) were performed and insufficient response to both tests was required for the diagnosis of GH deficiency. RESULTS: Twenty-five patients were included in the study, the mean age was 27.4 ± 4.5 years and the median duration of infertility was 60 months (min:14, max:120). Two patients were GH deficient according to GST and 14 to ITT. Two patients (8%) showed lack of response on both tests and were diagnosed with GH deficiency. CONCLUSION: The rate of GH deficiency among women with unexplained infertility was 8% in this preliminary study. There is need for further studies with larger patient groups to verify the results.

Alterations in Serum miR-126-3p Levels over Time: A Marker of Pituitary Insufficiency following Head Trauma.

INTRODUCTION: Traumatic brain injuries (TBIs) pose a high risk of pituitary insufficiency development in patients. We have previously reported alterations in miR-126-3p levels in sera from patients with TBI-induced pituitary deficiency. METHODS: To investigate why TBI-induced pituitary deficiency develops only in some patients and to reveal the relationship between miR-126-3p with hormone axes, we used mice that were epigenetically modified with miR-126-3p at the embryonic stage. These modified mice were subjected to mild TBI (mTBI) according to the Marmarou's weight-drop model at 2 months of age. The levels of miR-126-3p were assessed at 1 and 30 days in serum after mTBI. Changes in miR-126-3p levels after mTBI of wild-type and miR-126-3p* modified mouse lines validated our human results. Additionally, hypothalamus, pituitary, and adrenal tissues were analyzed for transcripts and associated serum hormone levels. RESULTS: We report that miR-126-3p directly affects hypothalamus-pituitary-adrenal (HPA) axis upregulation and ACTH secretion in the acute phase after mTBI. We also demonstrated that miR-126-3p suppresses Gnrh transcripts in the hypothalamus and pituitary, but this is not reflected in serum FSH/LH levels. The increase in ACTH levels in the acute phase may indicate that upregulation of miR-126-3p at the embryonic stage has a protective effect on the HPA axis after TBI. Notably, the most prominent transcriptional response is found in the adrenals, highlighting their role in the pathophysiology of TBI. CONCLUSION: Our study revealed the role of miR-126-3p in TBI and pituitary deficiency developing after TBI, and the obtained data will significantly contribute to elucidating the mechanism of pituitary deficiency development after TBI and development of new diagnostic and treatment strategies.

Hypoprolactinemia. Does it matter? Redefining the hypopituitarism and return from a mumpsimus : "Absence of proof is not the proof of absence".

Prolactin (PRL) is secreted by the lactotroph cells in the anterior pituitary gland which is under inhibitory control of dopamine. The mature human PRL has more than 300 physiological actions including lactation, reproduction, homeostasis, neuroprotection, behavior, water and electrolyte balance, immunoregulation and embryonic and fetal development. PRL is involved in the growth and development of mammary gland, preparation of the breast for lactation in the postpartum period, synthesis of milk, and maintenance of milk secretion. Abnormalities in the synthesis and secretion of PRL may result in hyperprolactinemia or hypoprolactinemia. Although hyperprolactinemia has been extensively investigated in the literature, because of the subtle or unclearly defined symptoms, hypoprolactinemia is a less-known and neglected disorder. Failure of lactation is a well-known clinical manifestation of hypoprolactinemia. Recent studies reveal that hypoprolactinemia may have some effects beyond lactation such as increased risk for metabolic abnormalities including insulin resistance, abnormal lipid profile, obesity and sexual dysfunction. Very low level of PRL is suggested to be avoided in patients receiving dopamin agonist treatment to prevent unwanted effects of hypoprolactinemia. Another important point is that hypoprolactinemia is not included in the classification of hypopituitarism. Anterior pituitary failure is traditionally classified as isolated, partial and complete (panhypopituitarism) hypopituitarism regardless of prolactin level. Therefore, there are two kinds of panhypopituitarism: panhypopituitarism with normal or high PRL level and panhypopituitarism with low PRL level. In this review, we present two personal cases, discuss the diagnosis of hypoprolactinemia, hypoprolactinemia associated clinical picture and suggest to redefine the classification of hypopituitarism.

The effects of hypercortisolism on the frequency and magnitude of sleep EEG waves in patients with Cushing syndrome: A spectral analysis study.

OBJECTIVES: Our aim was to investigate the effects of endogenous chronic hypercortisolism on sleep electroencephalogram (EEG) and differences between the adrenocorticotropic hormone (ACTH)-dependent and independent Cushing Syndrome (CS) patients through a sleep spectral analysis program. METHODS: A total of 32 patients diagnosed as having endogenous CS (12 ACTH-dependent and 20 ACTH-independent) and a control group comprising 16 healthy individuals were included in the study. Polysomnographic analysis was performed. Blood samples were collected at 08:00 AM for analysis of ACTH and basal cortisol, and at 00:00 AM for midnight cortisol levels. The frequency and power of the slow wave activity (SWA), theta, alpha, and beta waves of the first and last non-rapid eye movement (NREM) cycles were measured with a spectral analysis program. RESULTS: The CS patient group had higher SWA power, especially in the first NREM cycle. In the ACTH-dependent group, SWA maximum and mean power values were higher in the frontal channels in the first NREM, compared to the last NREM sleep stage (p<0.05). CONCLUSION: Cortisol has been found to be associated with SWA waves, making these waves higher in power, especially in the first NREM phase. This difference was much less pronounced in the final NREM sleep stage. The difference between the first and last NREM sleep stages with respect to the power of SWA in the frontal channel in the ACTH-dependent group suggests that not only cortisol but also high levels of ACTH affect the power of slow waves during sleep.

Hypothalamic-Pituitary Axis Function and Adrenal Insufficiency in COVID-19 Patients.

The outbreak of COVID-19 has affected more than half a billion people worldwide and caused more than 6 million deaths since 2019. The responsible virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), primarily affects the lungs, but it has multisystemic effects. It is well known that dysfunction of multiple endocrine organs may occur during or after COVID-19. Impairment of the hypothalamic-pituitary-adrenal (HPA) axis is of utmost importance as it may lead to death if went undiagnosed. SARS-CoV-2 may cause both primary and secondary adrenal insufficiencies (AIs). The clinical manifestations of AI are generally non-specific and might be attributed to the complications caused by the infection itself. The underlying pathogenetic mechanisms were explained by the immunogenic, vascular effects of the infection or the direct effects of the virus. The diagnosis of AI in critically ill patients with COVID-19 is not straightforward. There is lack of consensus on the cut-off values of basal serum cortisol levels and stimulation tests during the disease. Here we review the literature with a special regard on the evaluation of the HPA axis in patients with COVID-19. We conclude that the possibility of AI should always be kept in mind when dealing with patients with COVID-19, and repeated basal cortisol measurements and the ACTH stimulation test results could guide the clinician during the diagnostic process.

Idiopathic hirsutism: Is it really idiopathic or is it misnomer?

Hirsutism, which is characterized by excessive growth of terminal hair in a male pattern, may result from various causes including polycystic ovary syndrome (PCOS), non-classic congenital adrenal hyperplasia, adrenal or ovarian tumors or it may be idiopathic. Idiopathic hirsutism is currently defined as hirsutism associated with normal ovulatory function, normal serum androgen levels and normal ovarian morphology, however, the pathogenesis of idiopathic hirsutism is not clear. The androgens are the main hormones to stimulate growth of body hair, therefore, there should be any form of increased androgen effect irrespective of normal serum androgen levels in any patient with hirsutism. In accordance to this scientific truth, we have previously shown that, although within normal limits, patients with idiopathic hirsutism have relatively higher serum androgen levels (relative hyperandrogenemia) in comparison to healthy subjects which let as to think that is idiopathic hirsutism really idiopathic? In addition to relative hyperandrogenemia, we have previously shown that, in comparison to healthy subjects, women with idiopathic hirsutism demonstrated higher expression of steroid sulphatase and 17-beta hydroxysteroid dehydrogenase mRNA both in the subumbilical region and arm skin, which contributes to local androgen metabolism. Those results support the idea that, in some patients, although the adrenals or ovaries do not secrete increased amount of androgens leading to hyperandrogenemia, pilocebaceous unit locally produce increased amount of androgens leading to hirsutism without ovulatory dysfunction. Upon the demonstration of relative hyperandrogenemia and possible increase in local androgen synthesis in patients with idiopathic hirsutism, we think that idiopathic hirsutism is not idiopathic and it may be named as "normoandrogenic hirsutism". Furthermore, it may not be a different entity but may be an early stage of hyperandrogenic disorders such as PCOS. Clinically, this can be find out by following-up patients with idiopathic hirsutism prospectively.

Prediabetes and mild hepatosteatosis are associated with blunted cortisol response to glucagon but not to growth hormone.

BACKGROUND: Although there is a close relationship between cortisol and growth hormone (GH) levels, glucose intolerance and hepatosteatosis, changes in GH and the hypothalamo-pituitary-adrenal (HPA) axis were not previously studied in prediabetes. The main purpose of the present study was to assess changes in GH and HPA axis and their relationship with hepatosteatosis in prediabetic patients. METHODS: Forty prediabetic patients, with body-mass index (BMI) 25-35kg/m2, and 23 healthy individuals, with normal glucose tolerance and similar age and BMI, were included. The 75g oral glucose tolerance test and glucagon stimulation test (GST) were used. RESULTS: No significant differences were detected between prediabetic patients and healthy individuals in terms of insulin-like growth factor-1 (IGF-1), insulin-like growth factor-binding protein-3 (IGFBP-3), IGF-1/IGFBP3 ratio or adrenocorticotropic hormone (ACTH). GH responses to GST did not differ between groups. On the other hand, peak cortisol and area under the curve (AUC) (cortisol) response on GST were significantly lower in prediabetic patients. Both peak GH and AUC (GH) response on GST correlated negatively with waist circumference and body weight. The degree of hepatosteatosis correlated negatively with peak cortisol, GH, AUC (cortisol) and AUC (GH) response on GST. CONCLUSION: Cortisol response to GST is decreased in prediabetic patients, with relatively well conserved GH response. This suggests altered HPA axis responsiveness in prediabetes, as is known in diabetes. Thus, HPA axis changes in patients with diabetes probably start before the development of diabetes as such.

Case Report: A Novel Mutation Leading to 11-ß Hydroxylase Deficiency in a Female Patient.

BACKGROUND: 11ß hydroxylase deficiency (11ßOHD) ranks as the second most common enzyme deficiency that causes congenital adrenal hyperplasia. Depending on the severity of the enzyme deficiency, it can lead to cortisol deficiency, androgen excess and hypertension due to increased mineralocorticoid precursor levels. Many different types of mutations in the CYP11B1 gene located on chromosome 8q24.3 have been shown to cause 11ßOHD. Here, we report a novel missense mutation that leads to 11ßOHD in a female patient. CASE PRESENTATION: A 35-year-old female patient was admitted to the Endocrinology Department with a complaint of abdominal pain. The patient had a history of genital reconstruction surgery twice in childhood. On physical examination, an abdominal mass was detected. Laboratory examination of the patient revealed low levels of cortisol, potassium and high levels of ACTH, 11-deoxycortisol and androstenedione, suggesting 11ßOHD. Genotyping showed a novel homozygous missense mutation (c.1385T>C L462P variant) detected on the 8th chromosome where the CYP11B1 gene is located. Glucocorticoid therapy was commenced for the patient whose diagnosis of 11ßOHD was confirmed by both hormonal and genetic tests. A mass originating from the left adrenal gland with the largest diameter of 7 cm was compatible with myelolipoma. CONCLUSION: In this case report, we aimed to contribute to the literature by reporting a new missense mutation in the CYP11B1 gene, leading to classic type 11ßOHD that has not been described before.

The coexistence of newly diagnosed acromegaly with primary empty sella: More frequent than expected?

OBJECTIVE: We investigated the coexistence of newly diagnosed acromegaly with primary empty sella (ES), which is considered to be a rare association, and the impact of ES on the laboratory, radiological and prognostic status of acromegaly. DESIGN: Acromegaly patients diagnosed and followed-up between 2012 and 2021 were included. Empty sella was defined as the pituitary gland and adenoma filling <50% of the sella turcica on preoperative T1 magnetic resonance imaging (MRI). RESULTS: 102 acromegalic patients (45 male, 57 female, 45.5 ± 12.8 (range: 20-70 years) were included and data of a median 3 years (range: 0.5-9 years) were presented. ES was detected in 19 (18.6%) patients and 4 had complete and 15 had partial ES. Although not significant, adenoma size and residual adenoma on MRI on postoperative 3rd month, and disease remission at last control were lower in acromegaly with ES than in acromegaly without ES, while the rate of female gender and remission on postoperative 3rd month were higher. While preoperative serum prolactin and nadir GH responses to OGTT were significantly lower in patients with ES, there was no difference in terms of other pituitary hormones among both groups. CONCLUSION: The present study revealed the coexistence of newly diagnosed acromegaly with primary ES at a rate of nearly 20% which is more frequent than expected and this association is not rare. The presence of ES was not associated with any preoperative/postoperative pituitary hormone levels and remission status, except lower preoperative prolactin and nadir GH responses to OGTT.

The Role of Apoptosis and Autophagy in the Hypothalamic-Pituitary-Adrenal (HPA) Axis after Traumatic Brain Injury (TBI).

Traumatic brain injury (TBI) is a major health problem affecting millions of people worldwide and leading to death or permanent damage. TBI affects the hypothalamic-pituitary-adrenal (HPA) axis either by primary injury to the hypothalamic-hypophyseal region or by secondary vascular damage, brain, and/or pituitary edema, vasospasm, and inflammation. Neuroendocrine dysfunctions after TBI have been clinically described in all hypothalamic-pituitary axes. We established a mild TBI (mTBI) in rats by using the controlled cortical impact (CCI) model. The hypothalamus, pituitary, and adrenals were collected in the acute (24 h) and chronic (30 days) groups after TBI, and we investigated transcripts and protein-related autophagy (Lc3, Bcln1, P150, Ulk, and Atg5) and apoptosis (pro-caspase-3, cleaved caspase-3). Transcripts related to autophagy were reduced in the hypothalamus, pituitary, and adrenals after TBI, however, this was not reflected in autophagy-related protein levels. In contrast, protein markers related to apoptosis increased in the adrenals during the acute phase and in the pituitary during the chronic phase. TBI stresses induce a variation of autophagy-related transcripts without modifying the levels of their proteins in the HPA axis. In contrast, protein markers related to apoptosis are increased in the acute phase in the adrenals, which could lead to impaired communication via the hypothalamus, pituitary, and adrenals. This may then explain the permanent pituitary damage with increased apoptosis and inflammation in the chronic phase. These results contribute to the elucidation of the mechanisms underlying endocrine dysfunctions such as pituitary and adrenal insufficiency that occur after TBI. Although the adrenals are not directly affected by TBI, we suggest that the role of the adrenals along with the hypothalamus and pituitary should not be ignored in the acute phase after TBI.

Acromegaly is associated with a distinct oral and gut microbiota.

PURPOSE: Our aim was to investigate the changes in the composition of oral and gut microbiota in patients with newly diagnosed acromegaly and their relationship with IGF-1 levels. METHODS: Oral and fecal samples were collected from patients with newly diagnosed acromegaly without comorbidities and from healthy controls. The composition of the microbiota was analyzed. The general characteristics, oral and stool samples of the patients and healthy control subjects were compared. The changes in microbiota composition in both habitats, their correlations and associations with IGF-1 were statistically observed using machine learning models. RESULTS: Fifteen patients with newly diagnosed acromegaly without comorbidities and 15 healthy controls were included in the study. There was good agreement between fecal and oral microbiota in patients with acromegaly (p = 0.03). Oral microbiota diversity was significantly increased in patients with acromegaly (p < 0.01). In the fecal microbiota, the Firmicutes/Bacteroidetes ratio was lower in patients with acromegaly than in healthy controls (p = 0.011). Application of the transfer learned model to the pattern of microbiota allowed us to identify the patients with acromegaly with perfect accuracy. CONCLUSIONS: Patients with acromegaly have their own oral and gut microbiota even if they do not have acromegaly-related complications. Moreover, the excess IGF-1 levels could be correctly predicted based on the pattern of the microbiome.

The effect of additional acarbose on metformin-associated artificially high 18F-Fluorodeoxyglucose uptake in positron emission tomography/computed tomography.

AIM: Metformin causes diffuse and intense fluorodeoxyglucose (FDG) uptake more frequently in the colon and less frequently in the small intestine. In this study, we aimed to investigate the effect of simultaneous use of acarbose and metformin on FDG uptake in positron emission tomography/computed tomography (PET/CT), which has not been investigated previously. METHODS: Totally 145 patients with a median age of 65 years (range: 18-80 years), who underwent FDG PET/CT in the Department of Nuclear Medicine of Erciyes University Medical School between 2018 and 2021, were involved in the study. The patients undergoing PET/CT were categorized as metformin plus acarbose users (group MA), metformin users (group M), and control subjects without diabetes (group C). The maximum and mean standard uptake values (SUVmax and SUVmean) of FDG uptake of the all intestine segments were measured separately. RESULTS: The number of participants in each group was 35, 51 and 59 in group MA, group M and group C, respectively. The FDG uptake of all intestine was significantly higher in group MA and group M than in group C. The FDG uptake of ascending, transverse, descending, and sigmoid colon was significantly lower in group MA than in group M. The FDG uptake of the small intestine was not different between group MA and group M. The FDG uptake of the rectum was lower in group MA than group M and it was significant for SUVmean, but not significant for SUVmax. CONCLUSION: The addition of acarbose to metformin therapy decreased SUV and artificially high FDG uptake in the colon and may be an alternative recommendation to discontinuing metformin in patients going to PET/CT imaging.

The Importance of DHEA-S Levels in Cushing's Syndrome; Is There a Cut-off Value in the Differential Diagnosis?

The purpose of this study was to determine possible cut-off levels of basal DHEA-S percentile rank in the differential diagnosis of patients with Cushing's syndrome (CS) with ACTH levels in the gray zone and normal DHEA-S levels. In this retrospective study including 623 pathologically confirmed CS, the DHEA-S percentile rank was calculated in 389 patients with DHEA-S levels within reference interval. The patients were classified as group 1 (n=265 Cushing's disease; CD), group 2 (n=104 adrenal CS) and group 3 (n=20 ectopic ACTH syndrome).ROC-curve analyses were used to calculate the optimal cut-off level of DHEA-S percentile rank in the reference interval in the differential diagnosis of CS, and the effectiveness of this cut-off level in the identification of the accurate etiology of CS was assessed in patients who were in gray zone according to their ACTH levels. The DHEA-S percentile rank in the reference interval were significantly lower in group 2 compared to the other two groups (p<0.001), while group 1 and group 3 had similar levels. The optimal cut-off level of DHEA-S percentile rank in the reference interval providing differential diagnosis between group 1 and group 2 was calculated as 19.5th percentile (80.8% sensitivity, 81.5% specificity) and the level demonstrated the accurate etiology in 100% of CD and 76% of adrenal CS patients who were in the gray zone. This study showed that the cut-off value of DHEA-S level less than 20% of the reference interval could be used for differential diagnosis of CD and adrenal CS with high sensitivity and specificity, and it should be taken into the initial evaluation.

The potential impact of COVID-19 on thyroid gland volumes among COVID-19 survivors.

PURPOSE: Data about the effects of COVID-19 on the endocrine system are increasing over time. In the present study, we investigated the effects of COVID-19 on the thyroid gland among COVID-19 survivors by comparing them with healthy subjects. METHODS: Adult COVID-19 survivors who were managed and followed up in the Infectious Disease clinic were asked to participate in this study. COVID-19 survivors were recruited via a convenience sampling and those who agreed to participate in this study were seen by endocrinologists for assessments. The blood tests were obtained for thyroid antibodies and thyroid function tests. Thyroid ultrasonography (USG) was done by the same physician. The ellipsoid formula was used for the calculation of thyroid gland volume. RESULTS: 64 adult COVID-19 survivors and 70 control subjects were enrolled in the study. The COVID-19 survivors were evaluated at median 5.7 months (IQR: 4-6.5) (range: 2-7 months) after acute infection. The mean thyroid gland volume was significantly lower in COVID-19 survivors (10.3 ± 3.4 mL) than in the controls (14 ± 5.3 mL) (p = 0.001). There was no significant difference in free triiodothyronine (fT3), free thyroxine (fT4) and thyroid-stimulating hormone (TSH) levels between the groups. Among the twelve patients who had thyroid function evaluated in acute COVID-19, fT3 values were lower in acute COVID-19 than at the time of USG evaluation (3.04 ± 0.41 vs 3.47 ± 0.31 pg/mL), (p = 0.02). Among COVID-19 survivors, mild TSH elevation was detected in 4 (6.2%) patients and all of the other COVID-19 survivors (93.7%) were euthyroid. CONCLUSIONS: At 6 months after acute COVID, COVID-19 survivors had smaller thyroid gland volume than healthy controls, and only a few of the COVID-19 survivors had abnormal thyroid function.

Investigation of pituitary functions after acute coronavirus disease 2019.

Although coronavirus disease 2019 (COVID-19) mainly involves the lungs, it also affects many systems. The hypothalamic/pituitary axis is vulnerable to hypoxia, hypercoagulation, endothelial dysfunction and autoimmune changes induced by COVID-19 infection. Given that there is no extensive investigation on this issue, we investigated the pituitary functions three to seven months after acute COVID-19 infection. Forty-three patients after diagnosis of COVID-19 infection and 11 healthy volunteers were included in the study. In addition to the basal pituitary hormone levels, growth hormone (GH) and hypothalamo-pituitary adrenal (HPA) axes were evaluated by glucagon stimulation test (GST) and low-dose adrenocorticotropic hormone (ACTH) stimulation test, respectively. The peak cortisol responses to low-dose ACTH test were insufficient in seven (16.2%) patients. Twenty (46.5%) and four (9.3%) patients had inadequate GH and cortisol responses to GST, respectively. Serum insulin-like growth factor-1 (IGF-1) values were also lower than age and sex-matched references in four (9.3%) patients. The peak GH responses to GST were lower in the patient group when compared to the control group. Other abnormalities were mild thyroid-stimulating hormone elevation in four (9.3%) patients, mild prolactin elevation in two (4.6%) patients and central hypogonadism in four (9.3%) patients. Mean total testosterone values were lower in male patients when compared to male controls; however, the difference was not significant. These findings suggest that COVID-19 infection may affect pituitary functions, particularly the HPA and GH axes. These insufficiencies should be kept in mind in post-COVID follow-up. Long-term data are needed to determine whether these deficiencies are permanent or not.