High body mass index and night shift work are associated with COVID-19 in health care workers.

OBJECTIVE: To assess the magnitude of COVID-19 spread and the associated risk factors among health care workers (HCWs), we conducted an in-hospital survey in a central Italian COVID Hospital. METHODS: Participants underwent nasopharyngeal swab and/or serum collection for SARS-CoV-2 IgG examination. We divided participants according to working status, into rotating-night shift workers (r-NSW) and day-workers. RESULTS: We found 30 cases of COVID-19 infection in a total of 1180 HCWs (2.5%). Most COVID-19-positive hospital employees were r-NSWs with significantly higher BMI than that of individuals who tested negative. After adjustment for covariates, night work and BMI > 30 were associated with a markedly greater risk of COVID-19 diagnosis (OR 3.049 [95%CI 1.260-7.380] and OR 7.15 [95%CI 2.91-17.51], respectively). CONCLUSIONS: Our results describe a low prevalence of COVID-19 infection among HCWs at a central Italian COVID Hospital. COVID-19 infection risk appears to be associated with obesity and night shift work, thus supporting the need for careful health surveillance among frontline HCWs exposed to COVID-19.

Monthly fluctuations in 25-hydroxy-vitamin D levels in day and rotating night shift hospital workers.

PURPOSE: Epidemiological studies have suggested that indoor hospital employees, either day or night shift workers, are at high risk of metabolic and cardiovascular diseases. Interestingly, previous reports have also described a higher prevalence of vitamin D (25OHD) deficiency among these workers. However, few studies have determined the monthly variations in 25OHD levels in indoor hospital employees. METHODS: To address this lack of knowledge, in 2018, during the periodic health surveillance checks at the Service of Occupational Medicine, we measured 25OHD levels in a group of indoor hospital workers (88 rotating night shift workers vs 200 day workers). Each participant received a single annual health surveillance check. RESULTS: The mean levels of 25OHD were consistently below the lower limit of the normal range in both groups throughout the year. Only in the summer, day workers but not rotating night shift workers (mean 25.9 ± 11.3 ng/ml vs 23.1 ± 9.1 ng/ml; p = 0.042) showed levels significantly higher than those in the other seasons. This difference remained statistically significant even after correction for study covariates [ß = -  1.649 (CI - 0.283/- 3.482), p = 0.039]. A cosinor analysis confirmed that the difference in the 25OHD levels between groups was present later in the year. CONCLUSIONS: We found that relatively young healthy hospital workers, especially those with rotating night shifts, in the absence of significant metabolic risk factors, have a high risk of 25OHD deficiency/insufficiency. Because 25OHD deficiency may lead to a progression to more severe conditions such as osteoporosis or bone fractures, our results should be verified in larger cohorts including different ancestries.

A genetic marker of hyperuricemia predicts cardiovascular events in a meta-analysis of three cohort studies in high risk patients.

INTRODUCTION: The strongest genetic marker of uric acid levels, the rs734553 SNP in the GLUT9 urate transporter gene, predicts progression to kidney failure in CKD patients and associates with systolic BP and carotid intima media thickness in family-based studies. METHODS: Since genes are transmitted randomly (Mendelian randomization) we used this gene polymorphism as an unconfounded research instrument to further explore the link between uric acid and cardiovascular disease (cardiovascular death, and non-fatal myocardial infarction and stroke) in a meta-analysis of three cohort studies formed by high risk patients (MAURO: 755 CKD patients; GHS: 353 type 2 diabetics and coronary artery disease and the TVAS: 119 patients with myocardial infarction). RESULTS: In separate analyses of the three cohorts, the incidence rate of CV events was higher in patients with the rs734553 risk (T) allele (TT/GT) than in those without (GG patients) and the HR in TT/GT patients in the three cohorts (range 1.72-2.14) coherently signaled an excessive cardiovascular risk with no heterogeneity (I2 = 0.01). The meta-analytical estimate (total number of patients, n = 1227; total CV events, n = 222) of the HR for the combined end-point in TT/GT patients was twice higher (pooled HR: 2.04, 95% CI: 1.11-3.75, P = 0.02) than in GG homozygotes. CONCLUSIONS: The T allele of the rs734553 polymorphism in the GLUT9 gene predicts a doubling in the risk for incident cardiovascular events in patients at high cardiovascular risk. Findings in this study are compatible with the hypothesis of a causal role of hyperuricemia in cardiovascular disease in high risk conditions.

First Report of Plum pox virus Strain M Isolates in Apricot in Sicily, Italy.

Sharka or plum pox disease is one of the most economically important virus diseases of stone fruits. Plum pox virus (PPV), the causal agent, is a member of the genus Potyvirus of the family Potyviridae transmitted by aphids in a non-persistent manner and by grafting. To date, nine PPV strains have been described on the basis of their biological, serological, and molecular properties: M and D are the most widespread and economically important strains, PPV-Rec and PPV-C have been reported mainly in Europe, PPV-EA confined to Egypt, PPV-T to Turkey, PPV-W from Canada, Ukraine, Latvia, and Russia, PPV-CR detected in Russia, and finally a putative PPV strain infecting plum in Albania described as the ancestor of the M. PPV-M is responsible for major epidemics in many Italian regions and despite phytosanitary measures, the infection rate increases each year. The D and Rec isolates are sporadically reported while PPV-C, once signaled in Apulia, has been successfully eradicated. Except for a report from the 1980s, which is no longer traceable, Sicily was considered free from the virus (2). In 2012, two new foci of sharka in a coastal area of Catania in Sicily were first reported by the national plant protection service to the European Commission (DG-SANCO). In spring 2013, plants of different varieties of apricot (Prunus armeniaca) and peach (P. persica) showing typical symptoms of flower color break, yellowing and leaf deformation, chlorotic spots or rings, and malformation on fruits were tested positive to PPV by DAS-ELISA using polyclonal antibodies. In order to characterize two isolates from apricot varieties (Carmen Top and Ninfa), total RNAs, extracted using the RNeasy Plant Mini Kit (Qiagen) from ELISA-positive samples, were analyzed by RT-PCR with primers P1/P2, targeting the 3'-terminal region of the coat protein (CP) gene (5) followed by RFLP analysis after digestion with Rsa1. Subsequently total RNAs were analyzed with the type-specific primers P1/PM and P1/PD (3), P3M/P4b and P3D/P4b amplifying the N-terminal region of the CP gene (1) and, finally, with primers mD5/mD3, mM5/mM3, and mD5/mM3, amplifying the region 3'NIb-5'CP, including the recombination site of Rec isolates (4). Only primer pairs P1/P2, P1/PM, P3M/P4b, and mM5/mM3 produced amplicons of the expected size (243, 198, 466, and 459 bp, respectively). The RFLP assay confirmed both isolates belonging to the M strain. Moreover, no reaction was obtained with primer pair mD5/mM3, excluding isolates belonging to Rec-type. Isolate characterization was completed by direct sequencing in both directions of the of P1/P2 and P3M/P4b amplicons obtained from apricot samples L9-1 (Carmen Top isolate) and 9-335 (Ninfa isolate). The P1/P2 sequences (KJ994235, KJ994237) showed 98% similarity with PPV-M or PPV-Rec isolates. The P3M/P4b sequences (KJ994236, KJ994238) confirmed that Sicilian isolates belong to the PPV-M strain showing 99% similarity with those already present in GenBank, thus ruling out the possibility of an infection with a PPV-Rec isolate. This outbreak of the Marcus strain of PPV in Sicily represents a high risk for the expanding production of stone fruit in southern Italy. An eradication plan was quickly activated by the regional phytosanitary service. References: (1) T. Candresse et al. Phytopathology 101:611, 2011. (2) EPPO. PQR-EPPO database on quarantine pests (available online). http://www.eppo.int , 2014. (3) A. Olmos et al. J. Virol. Methods 68:127, 1997. (4) Z. Subr et al. Acta Virol. 48:173, 2004. (5) T. Wetzel et al. J. Virol. Methods 33:355, 1991.

Oxidative stress, glutathione status, sirtuin and cellular stress response in type 2 diabetes.

Oxidative stress has been suggested to play a main role in the pathogenesis of type 2 diabetes mellitus and its complications. As a consequence of this increased oxidative status a cellular adaptive response occurs requiring functional chaperones, antioxidant production and protein degradation. This study was designed to evaluate systemic oxidative stress and cellular stress response in patients suffering from type 2 diabetes and in age-matched healthy subjects. Systemic oxidative stress has been evaluated by measuring plasma reduced and oxidized glutathione, as well as pentosidine, protein carbonyls lipid oxidation products 4-hydroxy-2-nonenal and F2-isoprostanes in plasma, and lymphocytes, whereas the lymphocyte levels of the heat shock proteins (HSP) HO-1, Hsp72, Sirtuin-1, Sirtuin-2 and thioredoxin reductase-1 (TrxR-1) have been measured to evaluate the systemic cellular stress response. Plasma GSH/GSSG showed a significant decrease in type 2 diabetes as compared to control group, associated with increased pentosidine, F2-isoprostanes, carbonyls and HNE levels. In addition, lymphocyte levels of HO-1, Hsp70, Trx and TrxR-1 (P<0.05 and P<0.01) in diabetic patients were higher than in normal subjects, while sirtuin-1 and sirtuin-2 protein was significantly decreased (p<0.05). In conclusion, patients affected by type 2 diabetes are under condition of systemic oxidative stress and, although the relevance of downregulation in sirtuin signal has to be fully understood, however induction of HSPs and thioredoxin protein system represent a maintained response in counteracting systemic pro-oxidant status. This article is part of a Special Issue entitled: Antioxidants and Antioxidant Treatment in Disease.

Leg weakness in a lung transplant patient.

Progressive multifocal leukoencephalopathy (PML) is associated with JC polyomavirus (JCV) infection of central nervous system oligodendrocytes resulting in demyelinization and progressive focal neurologic deficits. Reactivation of dormant JCV occurs in the setting of immunosuppression, most commonly in patients with human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) or hematological malignancies. PML has also been reported in solid organ transplant recipients. We report the case of a 61-year-old man after bilateral lung transplantation for chronic hypersensitivity pneumonitis who presented with leg weakness, cognitive decline, and expressive aphasia at 5 months post transplantation. Magnetic resonance imaging and brain biopsy were consistent with PML. Treatment attempt with cytarabine was unsuccessful, and immunomodulation resulted in recurrent grade A3 rejection. The difficulty of managing PML in lung transplant patients is highlighted by the lack of directed therapy and risk of graft rejection or failure with attempts at decreasing immunosuppression.

High density cholesterol level as predictor of clinical response to anti-TNF-alpha therapy in psoriatic patients.

Psoriasis is a common, chronic, inflammatory, and debilitating disease of the skin. Infliximab is a human/mouse chimeric anti-TNF-alpha antibody effective in the management of psoriasis. Availability of biomarkers for prediction of response, could optimize the therapeutic approach. The aim of this study was to identify predictors of clinical response to infliximab in psoriatic patients in the long-term treatment. Patients affected with psoriasis and suitable for treatment with infliximab were prospectively enrolled. Patients treated for a period longer than 96 weeks were included in the study and divided into high responders and low responders according to infliximab efficacy (PASI 90). A logistic regression analysis was used to explore independent association between high clinical response and possible biomarkers of prediction. A total of 112 patients were included for the analysis. Multiple regression analysis showed that high levels of HDL cholesterol and the short duration of psoriasis [OR 1.11 (CI 1.05-1.18) and OR 0.94 (CI 0.89-0.99)] predicted the most effective clinical response to infliximab. Our findings, which highlight a possible role for HDL cholesterol as clinical predictor for psoriasis treatment, are particularly noteworthy in the context of clinical strategies, but also suggest a possible role for lipid metabolism in aspects of psoriasis that deserves further investigation.

Dolutegravir plus lamivudine dual therapy - a new option for initial antiretroviral therapy.

The current standard of care for treating HIV infection is the use of three antiretroviral drugs: a combination of two nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) and a third agent from either the integrase strand transfer inhibitor (INSTI), boosted protease inhibitor (PI) or non-nucleoside reverse transcriptase inhibitor (NNRTI) classes. In an effort to minimize the long-term adverse effects and cost of antiretroviral therapy, the use of regimens with fewer drugs in the combination has been under active investigation. To this end, the combination of dolutegravir (DTG) plus lamivudine (3TC), two antiretroviral drugs with a long track record of efficacy and safety in the treatment of HIV infection, is undergoing clinical evaluation in treatment-naive HIV-infected participants. The promising results of the PADDLE study, with 90% of study participants achieving the primary endpoint of HIV-1 RNA lower than 50 copies/mL, were confirmed by the results of ACTG A5353, a phase II, single-arm, open-label study. Subsequently, GEMINI-1 and -2, two phase III, double-blind, noninferiority studies, compared DTG + 3TC to a three-drug regimen of DTG, tenofovir disoproxil fumarate and emtricitabine in 1,433 antiretroviral treatment-naive adults, and demonstrated noninferior efficacy at 48 weeks with no emergence of NRTI or INSTI mutations and a more favorable safety profile. This dual regimen should be avoided in those patients with existing mutations and chronic hepatitis B virus infection. In addition, data in patients with CD4 counts less than 200/mm3 is limited.

Bictegravir, a novel integrase inhibitor for the treatment of HIV infection.

Bictegravir (BIC), a second-generation integrase strand transfer inhibitor (INSTI) approved for HIV treatment in fixed-dose combination with emtricitabine and tenofovir alafenamide, has potent antiviral activity in vitro to wild-type virus and strains with resistance to first-generation INSTIs. As part of combination therapy, BIC's virologic suppression rates in clinical trials are comparable to those of first-line combination antiretroviral drug regimens. BIC has demonstrated a high genetic barrier to resistance development in vitro, can be administered with or without food, and has a bioavailability of > 70%. A median plasma half-life of 18 hours allows once-daily dosing. Clearance is primarily hepatic through cytochrome P450 3A4 (CYP3A4) oxidation and UDP-glucuronosyltransferase 1A1 (UGT1A1) glucuronidation. Thus, potent inducers of UGT1A1 and CYP3A4 (e.g., rifamycins/anticonvulsants) should be avoided due to significantly decreased BIC serum exposure. Chelation with polyvalent cations can decrease absorption; otherwise, drug-drug interactions are few. BIC is well tolerated; diarrhea, nausea and headache are the main adverse effects associated with its use.

Ibalizumab for the treatment of multidrug-resistant HIV-1 infection.

Ibalizumab, a humanized monoclonal antibody to CD4, was recently approved by the United States Food and Drug Administration (FDA) for the treatment of HIV-1 infection in heavily treatment-experienced adults with multidrug-resistant HIV-1 infection failing their current antiretroviral regimen. Ibalizumab is the first in a new class of antiretroviral drugs designated as post-attachment inhibitors. It exerts its antiviral effect by noncompetitive binding of CD4, thereby blocking conformational changes in the CD4-gp120 complex that are essential for viral entry. Clinical studies have demonstrated ibalizumab's significant antiviral activity in patients with advanced HIV disease and extensive treatment experience, who had limited treatment options. Ibalizumab is administered intravenously at a dose of 800 mg every 2 weeks following a single intravenous loading dose of 2000 mg. The most common adverse reactions reported with the use of ibalizumab are diarrhea, dizziness, nausea and rash.

Glecaprevir/pibrentasvir for the treatment of chronic hepatitis C virus infection in adults.

The fixed-dose combination of glecaprevir (GLE), a nonstructural protein 3/4A (NS3/4A) protease inhibitor, and pibrentasvir (PIB), an NS5A inhibitor, was recently approved for the treatment of adult patients with chronic hepatitis C virus (HCV) genotypes 1-6 (GT-1-6) without cirrhosis or with compensated cirrhosis, and for the treatment of HCV GT-1 patients who have failed treatment with either NS5A inhibitors or NS3/4A protease inhibitors, but not both. This combination, administered over 8 or 12 weeks, has resulted in high cure rates in all six HCV genotypes, including patients with HIV coinfection. GLE/PIB was well tolerated, with the most common adverse events being headache and fatigue. GLE/PIB is recommended to be taken as three tablets (total daily dose: GLE 300 mg and PIB 120 mg) orally once daily with food. No dose adjustment is required in patients with any degree of renal impairment or in patients undergoing hemodialysis. Dose adjustment is also not required in patients with Child-Pugh A liver disease. However, the use of GLE/PIB is not recommended in patients with moderate (Child-Pugh B) or severe (Child-Pugh C) hepatic impairment.

Detection of Multiple Infections of Citrus exocortis viroid, Citrus viroid III, and Hop stunt viroid Variants in Hunan Province, China.

Citrus cultivation in China has increased since the late 1970s, with China now having the largest area of citrus in culture in the world that is spread in 22 provinces and municipalities. Hunan Province has undergone a program to become one of the major citrus producers in China. Poncirus trifoliata is the main rootstock, so citrus viroids are a limiting factor for further citriculture development. In mainland China, only the presence of Citrus exocortis viroid (CEVd) has been reported from Etrog citron indexing, sPAGE (sequential polyacrylamide gel electrophoresis) analysis (2), and reverse transcription (RT)-PCR (3). Three viroid-like RNAs, a1, b1, and d, based on sPAGE patterns were detected years ago in our laboratory in budsticks received from Sichuan Province. To identify different viroids and determine their distribution, a survey has been undertaken. Field trees showing stunting, bark scaling and cracking of the rootstock, and poor yield were tested using biological indexing and PCR for the most frequent citrus viroids. Samples from six trees of a local sweet orange variety and three of a Clementine variety introduced from abroad, both grafted on P. trifoliata and showing a variable degree of bark scaling and cracking, were collected near Changsha and in the County of Xin Ning at the end of summer 2006. Small pieces of bark were inserted in stems of young E. citron budwood grafted on rough lemon and maintained in a warm greenhouse (24 to 32°C). Indexing on E. citron showed mild epinasty and leaf roll typical of citrus viroid infections. To identify specific viroids, bark was ground to a fine powder with liquid nitrogen and total RNA was extracted with TRIZOL Reagent (Invitrogen, San Diego, CA) and tested by RT-PCR to detect CEVd, Hop Stunt viroid (HSVd), and Citrus viroid III (CVd-III), as well as to identify the cachexia variants of HSVd. Four primer pairs were used to test the RNA extracts by RT-PCR (1). All samples were infected by HSVd, eight with CVd-III, and six with CEVd. The cachexia variants of HSVd were detected in four of nine samples. Mixed infections were as follows: one sample had CEVd and HSVd, eight had HSVd and CVd-III, and five were infected by the three viroids. A second sampling 3 months after inoculation gave the same amplification patterns. The results show that at least three viroids are present in citrus orchards in Hunan Province. To our knowledge, this is the first report of cachexia variants of HSVd and CVd-III in China. The common occurrence of these viroids supports the need for proper indexing of mother trees and a specific shoot tip grafting program to create healthy budwood sources to provide healthy plants. References: (1) L. Bernard and N. Duran-Vila. Mol. Cell. Probes, 20:105, 2006. (2) L. Han et al. Viroids. CSIRO Publishing, Melbourne, 283, 2003. (3). Q. Hu et al. Acta Bot. Sin. 39:613, 1997.

Sofosbuvir/velpatasvir fixed-dose combination for the treatment of chronic hepatitis C virus infection.

The fixed-dose combination of sofosbuvir, a nucleotide analogue NS5B polymerase inhibitor, and velpatasvir, a second-generation NS5A inhibitor, has been approved by the United States Food and Drug Administration and the European Medicines Agency for the treatment of adult patients with chronic hepatitis C virus (HCV) genotype 1, 2, 3, 4, 5 or 6 infection. This combination, administered over 12 weeks as a single-tablet regimen, has resulted in high cure rates in all 6 HCV genotypes and in a variety of patient populations, including patients without cirrhosis, patients with compensated cirrhosis and patients with HIV coinfection. In patients with decompensated cirrhosis, high cure rates were also achieved over 12 weeks with sofosbuvir/velpatasvir plus ribavirin. Patients who had failed prior treatment with an NS5A-containing regimen were able to achieve high cure rates following 24 weeks of treatment with sofosbuvir/velpatasvir plus ribavirin. Sofosbuvir/velpatasvir was well tolerated, the most common adverse events being headache, fatigue and nausea.

Sofosbuvir/ledipasvir fixed-dose combination for treatment of chronic hepatitis C virus infection in children.

The United States Food and Drug Administration recently approved sofosbuvir and the fixed-dose combination of ledipasvir/sofosbuvir for the treatment of hepatitis C virus (HCV) infection in children ages 12 to 17. These are the first direct-acting antiviral treatments approved for children and adolescents with HCV. Pharmacokinetic data confirm equivalent drug exposure in this population as that found in adults during clinical trials. The efficacy and safety of these drugs has been shown in clinical trials.

Sharing the spotlight in Durban: A report from IAS TB2016 at AIDS2016.

Tuberculosis (TB) is now recognized as the number one cause of death worldwide due to a single infectious pathogen and is the cause of death in one-third of people living with HIV worldwide. An inaugural pre-conference focused on TB (TB2016) was held at the International AIDS Society Conference AIDS2016. This report focuses on key messages from the TB2016 conference that are important for the medical, public health, activist, and scientific communities.

Tenofovir alafenamide fumarate for the treatment of HIV infection.

Tenofovir alafenamide fumarate is a recently developed prodrug of tenofovir, a nucleotide analogue reverse transcriptase inhibitor with potent inhibitory activity against HIV. The utility of a previously developed tenofovir prodrug, tenofovir disoproxil fumarate, had been hampered by renal and bone mineral adverse events. Tenofovir alafenamide fumarate overcomes the shortcomings of tenofovir disoproxil fumarate by delivering high intracellular concentrations of the parent drug, tenofovir, while substantially reducing systemic exposure. Tenofovir alafenamide fumarate is currently available as a component of three fixed-dose products: i) coformulation with emtricitabine; ii) coformulation with elvitegravir, cobicistat and emtricitabine; and iii) coformulation with rilpivirine and emtricitabine.

Ledipasvir/sofosbuvir fixed-dose combination for treatment of hepatitis C virus genotype 4 infection.

Hepatitis C virus (HCV) genotype 4 accounts for 8-13% of all chronic HCV infections worldwide. Patients with HCV genotype 4 have been reported to have poor treatment responses to PEGylated interferon and ribavirin regimens. Recently a single tablet, fixed-dose combination of sofosbuvir, an RNA-directed RNA polymerase (NS5B) inhibitor, and ledipasvir, a nonstructural protein 5A (NS5A) inhibitor, has been approved for treatment of chronic HCV infection. Two studies using the fixed-dose combination in chronic HCV genotype 4 for 12 weeks reported sustained virologic response rates at 12 weeks (SVR12) of 93-95%. Data also support the use of ledipasvir/sofosbuvir in chronic HCV genotype 4 and HIV co-infection. Administered as a single once-daily oral regimen, this ribavirin- and interferon-free regimen is well tolerated, with low potential for adverse effects and represents a significant advancement in the treatment of chronic HCV genotype 4 infection.

Daclatasvir for the treatment of chronic hepatitis C virus infection.

Daclatasvir is a nonstructural protein 5A (NS5A) replication complex inhibitor that has shown potent in vitro activity against multiple hepatitis C virus (HCV) genotypes (GT). It is currently in advanced clinical development as a component of combination treatment regimens in a variety of HCV-infected patient populations. In studies conducted thus far, it has been generally well tolerated. It has been approved for the treatment of HCV GTs 1-4 in the European Union. The combination of daclatasvir and asunaprevir (an HCV NS3/4A protease inhibitor) has been approved in Japan for the treatment of patients with GT1 HCV infection. Here we review the available literature on daclatasvir, including its information on its discovery, mechanism of action, pharmacology, preclinical and clinical activity, resistance and safety.

Asunaprevir plus daclatasvir for the treatment of chronic hepatitis C virus infection.

Daclatasvir is a nonstructural protein 5A inhibitor of hepatitis C virus (HCV) replication. Asunaprevir is an NS3/4A complex inhibitor of HCV replication. The combination of daclatasvir and asunaprevir has been approved in Japan for the treatment of genotype 1 chronic HCV infection. In vitro studies have documented potent activity of these drugs, individually and in combination, against genotype 1 HCV. Results from completed and ongoing clinical studies have confirmed this potent activity in patients, with better responses noted in genotype 1b patients compared to patients with genotype 1a HCV. Response rates are also better in treatment-naive patients compared to those who are treatment-experienced; in these cases, the addition of interferon and ribavirin appears to enhance the treatment response. The combination of daclatasvir and asunaprevir is, in general, well tolerated. Daclatasvir and asunaprevir are substrates for cytochrome P450 3A4 enzymatic pathway; thus, there is a substantial potential for drug interactions.

Synthetic alpha-subunit peptides stimulate testosterone production in vitro by rat Leydig cells.

The glycoprotein hormones (LH, hCG, FSH, and TSH) have a common 92-amino acid alpha-subunit which is noncovalently linked to a hormone-specific beta-subunit. Synthetic peptides of the alpha-subunit have been shown to inhibit binding of [125I]iodo-hCG to rat ovarian membrane and [125I]iodo-TSH to human thyroid membrane preparations. Synthetic overlapping peptides of the alpha-subunit of hCG were prepared by solid phase techniques and tested in a standard in vitro rat Leydig cell bioassay. Three regions in the alpha-subunit (alpha 1-15, alpha 30-45, and alpha 71-85) were found to stimulate testosterone production. All three regions correlate with inhibition of hCG binding to ovarian receptors, but subtle differences exist between the binding sites and effector sites. These data indicate that the glycoprotein alpha-subunit has intrinsic bioactivity.