lncRNA LINC00941 modulates MTA2/NuRD occupancy to suppress premature human epidermal differentiation

Numerous long non-coding RNAs (lncRNAs) were shown to have a functional impact on cellular processes such as human epidermal homeostasis. However, the mechanism of action for many lncRNAs remains unclear to date. Here, we report that lncRNA LINC00941 regulates keratinocyte differentiation on an epigenetic level through association with the NuRD complex, one of the major chromatin remodelers in cells. We find that LINC00941 interacts with NuRD-associated MTA2 and CHD4 in human primary keratinocytes. LINC00941 perturbation changes MTA2/NuRD occupancy at bivalent chromatin domains in close proximity to transcriptional regulator genes, including the EGR3 gene coding for a transcription factor regulating epidermal differentiation. Notably, LINC00941 depletion resulted in reduced NuRD occupancy at the EGR3 gene locus, increased EGR3 expression in human primary keratinocytes, and increased abundance of EGR3-regulated epidermal differentiation genes in cells and human organotypic epidermal tissues. Our results therefore indicate a role of LINC00941/NuRD in repressing EGR3 expression in non-differentiated keratinocytes, consequentially preventing premature differentiation of human epidermal tissues.

Arabidopsis mRNA export factor MOS11: molecular interactions and role in abiotic stress responses

Transcription and export (TREX) is a multi-subunit complex that links synthesis, processing and export of mRNAs. It interacts with the RNA helicase UAP56 and export factors such as MOS11 and ALYs to facilitate nucleocytosolic transport of mRNAs. Plant MOS11 is a conserved, but sparsely researched RNA-binding export factor, related to yeast Tho1 and mammalian CIP29/SARNP. Using biochemical approaches, the domains of Arabidopsis thaliana MOS11 required for interaction with UAP56 and RNA-binding were identified. Further analyses revealed marked genetic interactions between MOS11 and ALY genes. Cell fractionation in combination with transcript profiling demonstrated that MOS11 is required for export of a subset of mRNAs that are shorter and more GC-rich than MOS11-independent transcripts. The central α-helical domain of MOS11 proved essential for physical interaction with UAP56 and for RNA-binding. MOS11 is involved in the nucleocytosolic transport of mRNAs that are upregulated under stress conditions and accordingly mos11 mutant plants turned out to be sensitive to elevated NaCl concentrations and heat stress. Collectively, our analyses identify functional interaction domains of MOS11. In addition, the results establish that mRNA export is critically involved in the plant response to stress conditions and that MOS11 plays a prominent role at this.

Biochemical and cellular insights into the Baz2B protein, a non-catalytic subunit of the chromatin remodeling complex

Baz2B is a regulatory subunit of the ATP-dependent chromatin remodeling complexes BRF1 and BRF5, which control access to DNA during DNA-templated processes. Baz2B has been implicated in several diseases and also in unhealthy ageing, however limited information is available on the domains and cellular roles of Baz2B. To gain more insight into the Baz2B function, we biochemically characterized the TAM (Tip5/ARBP/MBD) domain with the auxiliary AT-hook motifs and the bromodomain (BRD). We observed alterations in histone code recognition in bromodomains carrying cancer-associated point mutations, suggesting their potential involvement in disease. Furthermore, the depletion of Baz2B in the Hap1 cell line resulted in altered cell morphology, reduced colony formation and perturbed transcriptional profiles. Despite that, super-resolution microscopy images revealed no changes in the overall chromatin structure in the absence of Baz2B. These findings provide insights into the biological function of Baz2B.

Different elongation factors distinctly modulate RNA polymerase II transcription in Arabidopsis

Various transcript elongation factors (TEFs) including modulators of RNA polymerase II (RNAPII) activity and histone chaperones tune the efficiency of transcription in the chromatin context. TEFs are involved in establishing gene expression patterns during growth and development in Arabidopsis, while little is known about the genomic distribution of the TEFs and the way they facilitate transcription. We have mapped the genome-wide occupancy of the elongation factors SPT4-SPT5, PAF1C and FACT, relative to that of elongating RNAPII phosphorylated at residues S2/S5 within the carboxyterminal domain. The distribution of SPT4-SPT5 along transcribed regions closely resembles that of RNAPII-S2P, while the occupancy of FACT and PAF1C is rather related to that of RNAPII-S5P. Under transcriptionally challenging heat stress conditions, mutant plants lacking the corresponding TEFs are differentially impaired in transcript synthesis. Strikingly, in plants deficient in PAF1C, defects in transcription across intron/exon borders are observed that are cumulative along transcribed regions. Upstream of transcriptional start sites, the presence of FACT correlates with nucleosomal occupancy. Under stress conditions FACT is particularly required for transcriptional upregulation and to promote RNAPII transcription through +1 nucleosomes. Thus, Arabidopsis TEFs are differently distributed along transcribed regions, and are distinctly required during transcript elongation especially upon transcriptional reprogramming.

Functional involvement of septal miR-132 in extinction and oxytocin-mediated reversal of social fear

Social interactions are critical for mammalian survival and evolution. Dysregulation of social behavior often leads to psychopathologies such as social anxiety disorder, denoted by intense fear and avoidance of social situations. Using the social fear conditioning (SFC) paradigm, we analyzed expression levels of miR-132-3p and miR-124-3p within the septum, a brain region essential for social preference and avoidance behavior, after acquisition and extinction of social fear. Here, we found that SFC dynamically altered both microRNAs. Functional in vivo approaches using pharmacological strategies, inhibition of miR-132-3p, viral overexpression of miR-132-3p, and shRNA-mediated knockdown of miR-132-3p specifically within oxytocin receptor-positive neurons confirmed septal miR-132-3p to be critically involved not only in social fear extinction, but also in oxytocin-induced reversal of social fear. Moreover, Argonaute-RNA-co-immunoprecipitation-microarray analysis and further in vitro and in vivo quantification of target mRNA and protein, revealed growth differentiation factor-5 (Gdf-5) as a target of miR-132-3p. Septal application of GDF-5 impaired social fear extinction suggesting its functional involvement in the reversal of social fear. In summary, we show that septal miR-132-3p and its downstream target Gdf-5 regulate social fear expression and potentially mediate oxytocin-induced reversal of social fear.

Changes in adenoviral chromatin organization precede early gene activation upon infection

Within the virion, adenovirus DNA associates with the virus-encoded, protamine-like structural protein pVII. Whether this association is organized, and how genome packaging changes during infection and subsequent transcriptional activation is currently unclear. Here, we combined RNA-seq, MNase-seq, ChIP-seq, and single genome imaging during early adenovirus infection to unveil the structure- and time-resolved dynamics of viral chromatin changes as well as their correlation with gene transcription. Our MNase mapping data indicates that the adenoviral genome is arranged in precisely positioned nucleoprotein particles with nucleosome-like characteristics, that we term adenosomes. We identified 238 adenosomes that are positioned by a DNA sequence code and protect about 60-70 bp of DNA. The incoming adenoviral genome is more accessible at early gene loci that undergo additional chromatin de-condensation upon infection. Histone H3.3 containing nucleosomes specifically replaces pVII at distinct genomic sites and at the transcription start sites of early genes. Acetylation of H3.3 is predominant at the transcription start sites and precedes transcriptional activation. Based on our results, we propose a central role for the viral pVII nucleoprotein architecture, which is required for the dynamic structural changes during early infection, including the regulation of nucleosome assembly prior to transcription initiation. Our study thus may aid the rational development of recombinant adenoviral vectors exhibiting sustained expression in gene therapy.

High-resolution transcriptomic and epigenetic profiling identifies novel regulators of COPD

Patients with chronic obstructive pulmonary disease (COPD) are still waiting for curative treatments. Considering its environmental cause, we hypothesized that COPD will be associated with altered epigenetic signaling in lung cells. We generated genome-wide DNA methylation maps at single CpG resolution of primary human lung fibroblasts (HLFs) across COPD stages. We show that the epigenetic landscape is changed early in COPD, with DNA methylation changes occurring predominantly in regulatory regions. RNA sequencing of matched fibroblasts demonstrated dysregulation of genes involved in proliferation, DNA repair, and extracellular matrix organization. Data integration identified 110 candidate regulators of disease phenotypes that were linked to fibroblast repair processes using phenotypic screens. Our study provides high-resolution multi-omic maps of HLFs across COPD stages. We reveal novel transcriptomic and epigenetic signatures associated with COPD onset and progression and identify new candidate regulators involved in the pathogenesis of chronic lung diseases. The presence of various epigenetic factors among the candidates demonstrates that epigenetic regulation in COPD is an exciting research field that holds promise for novel therapeutic avenues for patients.

TFIIS Is Crucial During Early Transcript Elongation for Transcriptional Reprogramming in Response to Heat Stress

In addition to the stage of transcriptional initiation, the production of mRNAs is regulated during elongation. Accordingly, the synthesis of mRNAs by RNA polymerase II (RNAPII) in the chromatin context is modulated by various transcript elongation factors. TFIIS is an elongation factor that stimulates the transcript cleavage activity of RNAPII to reactivate stalled elongation complexes at barriers to transcription including nucleosomes. Since Arabidopsis tfIIs mutants grow normally under standard conditions, we have exposed them to heat stress (HS), revealing that tfIIs plants are highly sensitive to elevated temperatures. Transcriptomic analyses demonstrate that particularly HS-induced genes are expressed at lower levels in tfIIs than in wildtype. Mapping the distribution of elongating RNAPII uncovered that in tfIIs plants RNAPII accumulates at the +1 nucleosome of genes that are upregulated upon HS. The promoter-proximal RNAPII accumulation in tfIIs under HS conditions conforms to that observed upon inhibition of the RNAPII transcript cleavage activity. Further analysis of the RNAPII accumulation downstream of transcriptional start sites illustrated that RNAPII stalling occurs at +1 nucleosomes that are depleted in the histone variant H2A.Z upon HS. Therefore, assistance of early transcript elongation by TFIIS is required for reprogramming gene expression to establish plant thermotolerance.

Distinct role of subunits of the Arabidopsis RNA polymerase II elongation factor PAF1C in transcriptional reprogramming

Transcript elongation by RNA polymerase II (RNAPII) is dynamic and highly regulated, thereby contributing to the implementation of gene expression programs during plant development or in response to environmental cues. The heterohexameric polymerase-associated factor 1 complex (PAF1C) stabilizes the RNAPII elongation complex promoting efficient transcript synthesis. In addition, PAF1C links transcriptional elongation with various post-translational histone modifications at transcribed loci. We have exposed Arabidopsis mutants deficient in the PAF1C subunits ELF7 or CDC73 to elevated NaCl concentrations to provoke a transcriptional response. The growth of elf7 plants was reduced relative to that of wildtype under these challenging conditions, whereas cdc73 plants exhibited rather enhanced tolerance. Profiling of the transcriptional changes upon NaCl exposure revealed that cdc73 responded similar to wildtype. Relative to wildtype and cdc73, the transcriptional response of elf7 plants was severely reduced in accord with their greater susceptibility to NaCl. The data also imply that CDC73 is more relevant for the transcription of longer genes. Despite the fact that both ELF7 and CDC73 are part of PAF1C the strikingly different transcriptional response of the mutants upon NaCl exposure suggests that the subunits have (partially) specific functions.

Pronounced sequence specificity of the TET enzyme catalytic domain guides its cellular function

TET (ten-eleven translocation) enzymes catalyze the oxidation of 5-methylcytosine bases in DNA, thus driving active and passive DNA demethylation. Here, we report that the catalytic domain of mammalian TET enzymes favor CGs embedded within basic helix-loop-helix and basic leucine zipper domain transcription factor-binding sites, with up to 250-fold preference in vitro. Crystal structures and molecular dynamics calculations show that sequence preference is caused by intrasubstrate interactions and CG flanking sequence indirectly affecting enzyme conformation. TET sequence preferences are physiologically relevant as they explain the rates of DNA demethylation in TET-rescue experiments in culture and in vivo within the zygote and germ line. Most and least favorable TET motifs represent DNA sites that are bound by methylation-sensitive immediate-early transcription factors and octamer-binding transcription factor 4 (OCT4), respectively, illuminating TET function in transcriptional responses and pluripotency support.

Phosphorylation of the FACT histone chaperone subunit SPT16 affects chromatin at RNA polymerase II transcriptional start sites in Arabidopsis

The heterodimeric histone chaperone FACT, consisting of SSRP1 and SPT16, contributes to dynamic nucleosome rearrangements during various DNA-dependent processes including transcription. In search of post-translational modifications that may regulate the activity of FACT, SSRP1 and SPT16 were isolated from Arabidopsis cells and analysed by mass spectrometry. Four acetylated lysine residues could be mapped within the basic C-terminal region of SSRP1, while three phosphorylated serine/threonine residues were identified in the acidic C-terminal region of SPT16. Mutational analysis of the SSRP1 acetylation sites revealed only mild effects. However, phosphorylation of SPT16 that is catalysed by protein kinase CK2, modulates histone interactions. A non-phosphorylatable version of SPT16 displayed reduced histone binding and proved inactive in complementing the growth and developmental phenotypes of spt16 mutant plants. In plants expressing the non-phosphorylatable SPT16 version we detected at a subset of genes enrichment of histone H3 directly upstream of RNA polymerase II transcriptional start sites (TSSs) in a region that usually is nucleosome-depleted. This suggests that some genes require phosphorylation of the SPT16 acidic region for establishing the correct nucleosome occupancy at the TSS of active genes.

Versatile workflow for cell type-resolved transcriptional and epigenetic profiles from cryopreserved human lung

Complexity of lung microenvironment and changes in cellular composition during disease make it exceptionally hard to understand molecular mechanisms driving development of chronic lung diseases. Although recent advances in cell type-resolved approaches hold great promise for studying complex diseases, their implementation relies on local access to fresh tissue, as traditional tissue storage methods do not allow viable cell isolation. To overcome these hurdles, we developed a versatile workflow that allows storage of lung tissue with high viability, permits thorough sample quality check before cell isolation, and befits sequencing-based profiling. We demonstrate that cryopreservation enables isolation of multiple cell types from both healthy and diseased lungs. Basal cells from cryopreserved airways retain their differentiation ability, indicating that cellular identity is not altered by cryopreservation. Importantly, using RNA sequencing and EPIC Array, we show that gene expression and DNA methylation signatures are preserved upon cryopreservation, emphasizing the suitability of our workflow for omics profiling of lung cells. Moreover, we obtained high-quality single-cell RNA-sequencing data of cells from cryopreserved human lungs, demonstrating that cryopreservation empowers single-cell approaches. Overall, thanks to its simplicity, our workflow is well suited for prospective tissue collection by academic collaborators and biobanks, opening worldwide access to viable human tissue.

Characterizing the nuclease accessibility of DNA in human cells to map higher order structures of chromatin

Packaging of DNA into chromatin regulates DNA accessibility and consequently all DNA-dependent processes. The nucleosome is the basic packaging unit of DNA forming arrays that are suggested, by biochemical studies, to fold hierarchically into ordered higher-order structures of chromatin. This organization has been recently questioned using microscopy techniques, proposing an irregular structure. To address the principles of chromatin organization, we applied an in situ differential MNase-seq strategy and analyzed in silico the results of complete and partial digestions of human chromatin. We investigated whether different levels of chromatin packaging exist in the cell. We assessed the accessibility of chromatin within distinct domains of kb to Mb genomic regions, performed statistical analyses and computer modelling. We found no difference in MNase accessibility, suggesting no difference in fiber folding between domains of euchromatin and heterochromatin or between other sequence and epigenomic features of chromatin. Thus, our data suggests the absence of differentially organized domains of higher-order structures of chromatin. Moreover, we identified only local structural changes, with individual hyper-accessible nucleosomes surrounding regulatory elements, such as enhancers and transcription start sites. The regulatory sites per se are occupied with structurally altered nucleosomes, exhibiting increased MNase sensitivity. Our findings provide biochemical evidence that supports an irregular model of large-scale chromatin organization.

Nucleosomes Stabilize ssRNA-dsDNA Triple Helices in Human Cells

Chromatin-associated non-coding RNAs modulate the epigenetic landscape and its associated gene expression program. The formation of triple helices is one mechanism of sequence-specific targeting of RNA to chromatin. With this study, we show an important role of the nucleosome and its relative positioning to the triplex targeting site (TTS) in stabilizing RNA-DNA triplexes in vitro and in vivo. Triplex stabilization depends on the histone H3 tail and the location of the TTS close to the nucleosomal DNA entry-exit site. Genome-wide analysis of TTS-nucleosome arrangements revealed a defined chromatin organization with an enrichment of arrangements that allow triplex formation at active regulatory sites and accessible chromatin. We further developed a method to monitor nucleosome-RNA triplexes in vivo (TRIP-seq), revealing RNA binding to TTS sites adjacent to nucleosomes. Our data strongly support an activating role for RNA triplex-nucleosome complexes, pinpointing triplex-mediated epigenetic regulation in vivo.

CHD3 and CHD4 form distinct NuRD complexes with different yet overlapping functionality

CHD3 and CHD4 (Chromodomain Helicase DNA binding protein), two highly similar representatives of the Mi-2 subfamily of SF2 helicases, are coexpressed in many cell lines and tissues and have been reported to act as the motor subunit of the NuRD complex (nucleosome remodeling and deacetylase activities). Besides CHD proteins, NuRD contains several repressors like HDAC1/2, MTA2/3 and MBD2/3, arguing for a role as a transcriptional repressor. However, the subunit composition varies among cell- and tissue types and physiological conditions. In particular, it is unclear if CHD3 and CHD4 coexist in the same NuRD complex or whether they form distinct NuRD complexes with specific functions. We mapped the CHD composition of NuRD complexes in mammalian cells and discovered that they are isoform-specific, containing either the monomeric CHD3 or CHD4 ATPase. Both types of complexes exhibit similar intranuclear mobility, interact with HP1 and rapidly accumulate at UV-induced DNA repair sites. But, CHD3 and CHD4 exhibit distinct nuclear localization patterns in unperturbed cells, revealing a subset of specific target genes. Furthermore, CHD3 and CHD4 differ in their nucleosome remodeling and positioning behaviour in vitro. The proteins form distinct CHD3- and CHD4-NuRD complexes that do not only repress, but can just as well activate gene transcription of overlapping and specific target genes.

Extraction and analysis of signatures from the Gene Expression Omnibus by the crowd

Gene expression data are accumulating exponentially in public repositories. Reanalysis and integration of themed collections from these studies may provide new insights, but requires further human curation. Here we report a crowdsourcing project to annotate and reanalyse a large number of gene expression profiles from Gene Expression Omnibus (GEO). Through a massive open online course on Coursera, over 70 participants from over 25 countries identify and annotate 2,460 single-gene perturbation signatures, 839 disease versus normal signatures, and 906 drug perturbation signatures. All these signatures are unique and are manually validated for quality. Global analysis of these signatures confirms known associations and identifies novel associations between genes, diseases and drugs. The manually curated signatures are used as a training set to develop classifiers for extracting similar signatures from the entire GEO repository. We develop a web portal to serve these signatures for query, download and visualization.

Bioinformatic Analysis of ChIP-seq Data on the Repetitive Ribosomal RNA Gene

Ribosomal RNA genes are highly repetitive and therefore not annotated in genome assemblies. We did recently analyze the epigenetic and architectural regulation of murine ribosomal genes by the Transcription Termination Factor I and made use of genome-wide histone modification ChIP-seq data. This method paper describes how repetitive genomic regions can be integrated into custom genomic assemblies and be used with genome-wide profiling data.

TNFα signalling primes chromatin for NF-κB binding and induces rapid and widespread nucleosome repositioning

BACKGROUND

The rearrangement of nucleosomes along the DNA fiber profoundly affects gene expression, but little is known about how signalling reshapes the chromatin landscape, in three-dimensional space and over time, to allow establishment of new transcriptional programs.

RESULTS

Using micrococcal nuclease treatment and high-throughput sequencing, we map genome-wide changes in nucleosome positioning in primary human endothelial cells stimulated with tumour necrosis factor alpha (TNFα) - a proinflammatory cytokine that signals through nuclear factor kappa-B (NF-κB). Within 10 min, nucleosomes reposition at regions both proximal and distal to NF-κB binding sites, before the transcription factor quantitatively binds thereon. Similarly, in long TNFα-responsive genes, repositioning precedes transcription by pioneering elongating polymerases and appears to nucleate from intragenic enhancer clusters resembling super-enhancers. By 30 min, widespread repositioning throughout megabase pair-long chromosomal segments, with consequential effects on three-dimensional structure (detected using chromosome conformation capture), is seen.

CONCLUSIONS

Whilst nucleosome repositioning is viewed as a local phenomenon, our results point to effects occurring over multiple scales. Here, we present data in support of a TNFα-induced priming mechanism, mostly independent of NF-κB binding and/or elongating RNA polymerases, leading to a plastic network of interactions that affects DNA accessibility over large domains.

Knowledge and practices of family planning in Zimbabwe

OBJECTIVE

To assess the level of knowledge and use of family planning in Zimbabwe.

DESIGN

Cross sectional study.

SETTING

All eight provinces and two major cities in Zimbabwe.

SUBJECTS

Women of child bearing age (15 to 49 years, 6,083 respondents).

MAIN OUTCOME MEASURES

Number of live births, knowledge of contraceptive methods, previous, current and intention for future use of contraceptives, method related problems.

RESULTS

The contraceptive prevalence rate was 59.6% (CI 95% 58.4 to 60.9). The median number of live births was two (Q1 = 1, Q3 = 4) among all women, and seven (Q1 = 6, Q3 = 8) among women aged 40 to 49 years. Of 6,083 women interviewed, 5,849 (96.2%) knew at least one method of modern family planning, and 4,743 (78.0%) had ever used contraceptive in their life. Health concerns were the main reason for both discontinuation (28.5%) and postponement (22.8%) of contraceptive use.

CONCLUSIONS

As compared to the 1991 Mother and Child Health Survey, knowledge and coverage of family planning services have improved further, and the introduction of injectable contraceptives has proved a success. Areas which need attention include the groups with high parity that remain under served, the low knowledge and use of condoms as a contraceptive, and the high level of health concerns among current and potential users.

The impact of an inadequate municipal water system on the residents of Chinhoyi town, Zimbabwe

OBJECTIVE

To assess the use and impact of the water reticulation system in Chinhoyi on its residents.

DESIGN

Cross sectional and case series studies.

SETTING

Chinhoyi town.

SUBJECTS

600 Chinhoyi residents.

MAIN OUTCOME MEASURES

Practices and perceptions of Chinhoyi residents on the water system, and distribution of water-related diseases per area of residence.

RESULTS

Out of 600 respondents, 565 (99.3%) had access to piped water and 558 (98.0%) to flush toilets. Breakdowns of water supply and functioning of toilet facility were reported by 308 (77.0%) and 110 (28.0%) respondents in the previous six months, respectively. Main complaints of Chinhoyi residents were about low water quality (36.2%), inadequate sewage system (31.3%) and environmental pollution (26.5%). Cases of water-related diseases were not associated with natural water bodies.

CONCLUSIONS

Chinhoyi residents have good access to the municipal water and an adequate sanitation system. However, low quality of the water, frequent system breakdowns and the degradation and loss of amenity of the environment impair their quality of life.

In vivo testing of the therapeutic efficacy of chloroquine on falciparum malaria infections in Chirundu, Mashonaland West, Zimbabwe

OBJECTIVE

To detect the level of the in vivo chloroquine efficacy in falciparum malaria infections, in order to assess the need for change in the management and treatment of uncomplicated malaria.

DESIGN

Prospective descriptive study.

SETTING

Chirundu Rural Clinic, Mashonaland West Province.

SUBJECTS

63 patients confirmed by a positive blood slide for P. falciparum who attended Chirundu clinic, who were eligible for the study and, who also agreed to participate.

MAIN OUTCOME MEASURE(S)

Frequency of treatment success, early treatment failure and late treatment failure in uncomplicated patients treated with chloroquine.

RESULTS

Out of 63 cases enrolled and completely followed up, chloroquine treatment was effective in 54 cases (85.7%) and was not effective in nine cases (14.3%). All treatment failures were successfully treated with sulphadoxine + pyrimethamine (Fansidar) or quinine following the approved guidelines.

CONCLUSIONS

Chloroquine remains highly effective in the treatment of malaria due to P. falciparum in the Zambezi Valley of Hurungwe district and therefore, has to remain the first line drug. Likewise, guidelines for the use of sulphadoxine + pyrimethamine (Fansidar) or quinine as second line drugs, are adequate to the local situation. Health workers directly supervised the patients when they were swallowing the tablets during the whole course, and this without doubt, indirectly increased the efficacy of chloroquine. It is vital to confirm the malaria diagnosis on the spot appointing microscopists or distributing a limited stock of Parasight-F test.

Reduced O6-methylguanine repair in fibroblast cultures from patients with lung cancer

The activity of O6-methylguanine-DNA methyltransferase was determined in fibroblast cultures from 45 patients with lung cancer, 39 patients with cutaneous malignant melanoma, and 29 healthy controls. This enzyme is a critical parameter for the capacity to repair O6-methylguanine (O6-mGua) adducts in DNA, and a decreased activity might therefore be responsible for an enhanced susceptibility to cancer. The assay was performed with 8 x 10(6) fibroblasts which were homogenized and incubated with a known amount of O6-mGua containing DNA. The remaining substrate was determined fluorimetrically after high performance liquid chromatographic separation. O6-mGua repair was significantly reduced in lung cancer patients [6.64 +/- 4.32 (SD) pmol O6-methylguanine repaired/8 x 10(6) cells] as compared to healthy controls [10.35 +/- 5.42, P less than 0.0022] or patients with cutaneous malignant melanoma [10.83 +/- 6.66]. The lowest mean values were detected in a subgroup of 16 lung cancer patients with a tumor manifestation below 46 years of age (5.06 +/- 3.89). Fibroblasts from 4 patients with lung cancer had no detectable repair. We conclude that a reduced capacity to remove O6-mGua adducts may represent a further mechanism of individually enhanced lung cancer risk.

[Hyperthecosis ovarii--a tumor-like change in androgenized females]

Hyperthecosis has been repeatedly described as a disease entity separate from polycystic ovaries (PCO) as characterised by stromal luteinisation, obligatory virilism and purely ovarian androgen hypersecretion. This study compares the findings in patients with hyperthecosis (n = 10), PCO (n = 33) and androgen-secreting ovarian tumours (n = 7). It included selective ovarian-adrenal vein catheterisation with measurement of testosterone (T), dihydro-T, androstenedione, DHEA and its sulfate, 17 alpha-hydroxyprogesterone and cortisol before and after dexamethasone; determination of free T, oestrone, oestradiol and prolactin as well as LH and FSH before and after GnRH. In histologically proven hyperthecosis, signs of virilism were absent in 6 cases. A specific hormone profile could not be identified. Mixed ovarian-adrenal androgen hypersecretion was documented in 4 patients (purely ovarian: n = 6). Ovarian T output frequently fell within the tumour range (n = 4). It is concluded that the minor differences between hyperthecosis and PCO represent only variable manifestations of the same heterogeneous disturbance of androgen metabolism. However, it is of special clinical relevance to rule out a tumour in patients with hyperthecosis.

Gonadal and adrenal androgen secretion in hirsute females

The pathophysiology of glandular androgen hypersecretion must be regarded as a continuous process without sharp borderlines from normal to non-tumorous conditions, such as polycystic ovaries and hyperthecosis, to neoplastic disease. Hirsutism and related symptoms are most often caused by excess androgens of ovarian and/or adrenal origin, i.e. testosterone, dihydrotestosterone, delta 4-androstenedione, dehydroepiandrosterone and its sulphate. As demonstrated by selective catheterization of glandular effluents, combined hypersecretion occurs more frequently then either purely gonadal or adrenal overproduction. No correlation can be found between the type, frequency and extent of hormonal changes and the clinical, laparoscopic, angiographic, or histological findings. Dynamic function tests do not reliably discriminate between the various aetiological subgroups due to extremely variable and even non-specific individual responsiveness. Selective catheterization is presently the most sensitive method for the preoperative identification and localization of androgen-secreting neoplasms.

Technical difficulties of selective venous blood sampling in the differential diagnosis of female hyperandrogenism

To determine glandular steroid release of adrenals and ovaries in female hyperandrogenism, a standardized method for percutaneous transfemoral venous blood sampling was developed. In eight volunteers and 67 patients, catheterization was performed during the early follicular phase (days 3-7; between 8 and 10 a.m.) to reduce interference from cyclic and circadian variations of secretion. Serial samplings reduced the episodic effluent changes. Anatomical variations and collateral flow as well as stress effects and the dosage of contrast media were studied. During catheterization, peripheral cortisol levels did not differ significantly from control groups. Collaterals had no effect on hormone levels. Contrast media increased cortisol effluent levels only when they were sampled following venography. Four-vessel venous sampling was found to be indicated if peripheral testosterone was more than 1.5 ng/ml and/or dehydroepiandrosterone sulfate more than 6,700 ng/ml. If an ovarian (adrenal)/peripheral gradient of testosterone exceeded 2.7 ng/ml, surgical intervention for tumor removal at the site of hormone excess was felt to be necessary.

Oral contraceptives and pituitary response to GnRH: comparative study of progestin-related effects

GnRH double stimulation (2 X 25 micrograms i.v. at a two-hour interval) was used to assess the dynamics of LH and FSH release in 25 healthy women on oral contraceptives, all containing 50 micrograms of ethinylestradiol (EE). The study included two sequential regimens (50 micrograms EE X 7 days, 50 micrograms EE + 0.125 mg desogestrel X 15 days; 50 micrograms EE X 7 days, 50 micrograms EE + 2.5 mg lynestrenol X 15 days) and three combined preparations (biphasic: 50 micrograms EE + 1 mg norethisterone acetate (NETA) X 11 days, 50 micrograms EE + 2 mg NETA X 10 days; monophasic: 50 micrograms EE + 2 mg cyproterone acetate X 21 days; 50 micrograms EE + 2.5 mg lynestrenol X 21 days). The tests were always performed on days 19 to 21 of the first treatment cycle and compared to results obtained in normally cycling controls and in women receiving 50 micrograms EE daily alone. It was found that the EE-induced augmentation of pituitary responsiveness to GnRH is diminished by the addition of progestins. LH and FSH reactions to stimulation were both affected. The degree of inhibition depended not only on the chemical structure and daily dose of the progestin component, but also on the duration of its administration per treatment cycle.

[Polycystic ovaries: specific disease picture or nonspecific symptom?]

This study compares the clinical, biochemical and laparoscopic findings in androgenized patients with (n = 33) and without (n = 17) polycystic ovaries (PCO). It included selective ovarian-adrenal vein catheterisation with measurement of testosterone, dihydrotestosterone, delta 4-androstendione, dehydroepiandrosterone and its sulfate, 17 alpha-hydroxyprogesterone and cortisol in peripheral and glandular venous samples; determination of free testosterone, oestradiol, oestron, LH, FSH and prolactin in peripheral blood; GnRH and TRH double stimulation, as well as dexamethasone suppression tests. There was no correlation between the morphological, clinical, and endocrine changes. A PCO-specific hormonal pattern was not identifiable. Based on catheterisation data, combined ovarian-adrenal androgen hypersecretion was found in 46% of PCO cases; purely ovarian (21%) or adrenal (12%) overproduction were not as frequent. The dynamic function tests proved to be non-specific; e.g., dexamethasone suppressed not only adrenal, but also ovarian androgen output. It is concluded from these data that PCO are not a nosologic entity, but rather a non-obligatory sign of hyperandrogenism. Laparoscopy is, therefore, without clinical relevance in these patients with non-neoplastic hyperandrogenaemia.

Ovarian and adrenal vein steroids in seven patients with androgen-secreting ovarian neoplasms: selective catheterization findings

Standardized bilateral ovarian-adrenal vein catheterization was utilized to preoperatively assess glandular steroid release in seven consecutive cases of occult virilizing gonadal neoplasms. Peripheral testosterone (T) exceeded 1.5 ng/ml in all instances (range, 1.51 to 8.67 ng/ml). Endoscopy and radiography failed to locate the functional lesions. Catheterization showed a unilateral elevation of the ovarian-peripheral vein gradient for T greater than 2.7 ng/ml in six women. In the remaining patient, gradient analysis ruled out an adrenal tumor but did not facilitate lateralization of the gonadal lesion due to subselective ovarian effluent sampling. In addition to the consistent hypersecretion of T, variable excess gonadal output of dihydrotestosterone, androstenedione, dehydroepiandrosterone, and 17 alpha-hydroxyprogesterone was evident. Associated adrenal androgenic hyperfunction was documented in three subjects. Histologic evaluation of the implicated ovaries revealed three lipid cell, two Leydig cell, and two Sertoli-Leydig cell tumors, respectively, measuring between 0.6 and 2.2 cm in diameter. No correlation was found between any of the following parameters: peripheral or glandular vein steroid levels, androgen gradients, severity of symptoms, tumor morphology, and tumor size. In conclusion, appropriate application of selective catheterization may considerably reduce the frequency and extent of operative intervention.

[Differential use of sex hormones during the perimenopause]

Various regimens are available for hormone replacement in perimenopausal patients. Their pharmacodynamic effects differ e.g. in respect to the relief of subjective climacteric symptoms, the risk of endometrial cancer, the prevention of osteoporosis and the alterations of lipid metabolism. In view of the conflicting epidemiologic data general long-term prophylaxis in all climacteric women cannot be recommended at present. The institution of therapy requires valid indications and careful assessment of relative risks. Today, the cyclic administration of oral estrogen-progestin combinations may be regarded as the method of choice. However, treatment can and should be individualized. The practical aspects of a differential management are discussed. With prudent use, the benefits of perimenopausal hormone replacement clearly outweigh their potential disadvantages.

Ovarian and adrenal vein steroids in patients with nonneoplastic hyperandrogenism: selective catheterization findings

Standardized bilateral ovarian-adrenal vein catheterization was utilized to assess directly glandular steroid release in 60 androgenized women without evidence of a functional neoplasm. Testosterone (T), dihydrotestosterone (DHT), androstenedione (delta 4 A), dehydroepiandrosterone (DHEA), DHEA sulfate (DHEA-S), 17-hydroxyprogesterone (17-OHP), and cortisol (F) were measured by radioimmunoassay in samples obtained from a peripheral vein and the four glandular veins (all values are given as nanograms per milliliter, mean +/- standard deviation). Peripheral values were as follows: T, 0.68 +/- 0.43; DHT, 0.32 +/- 0.13; delta 4 A, 2.2 +/- 2.0; DHEA, 8.8 +/- 8.9; DHEA-S, 3137 +/- 1774; 17-OHP, 2.0 +/- 3.0; and F, 216 +/- 121. Peripheral elevations of at least one androgen were found in 80% of the 60 cases (T, 38%; DHT, 18%; delta 4 A, 50%; DHEA, 45%; and DHEA-S, 37%). Ovarian-peripheral vein gradients ( OPGs ) and adrenal-peripheral vein gradients ( APGs ) served as semiquantitative estimates of glandular secretion. OPGs were as follows: T, 0.4 +/- 1.1; DHT, 0.1 +/- 0.2; delta 4 A, 3.4 +/- 7.0; DHEA, 14.6 +/- 100; DHEA-S, -288 +/- 523; 17-OHP, 4.5 +/- 8.4; and F, -35 +/- 47. APGs were as follows: T, 0.88 +/- 1.3; DHT, 1.1 +/- 0.9; delta 4 A, 14.4 +/- 38.4; DHEA, 327 +/- 367; DHEA-S, 854 +/- 1223; 17-OHP, 20.8 +/- 41.3; and F, 1252 +/- 2023. Excess ovarian and/or adrenal androgen output was assumed in a given individual when one or more of the respective T, DHT, delta 4 A, DHEA, and DHEA-S gradients exceeded the upper 95% confidence limits of normal previously established in this laboratory.(ABSTRACT TRUNCATED AT 250 WORDS)

Ovarian and adrenal vein steroids in healthy women with ovulatory cycles--selective catheterization findings

Bilateral ovarian-adrenal vein catheterization and androgen measurements in the efferent samples were utilized to directly assess glandular steroid release in 8 healthy volunteers with proven ovulatory cycles during the early follicular phase. Side effects did not occur in any of the women. Hormone levels were as follows (mean +/- SD; ng/ml) T: peripheral vein (PV) 0.36 +/- 0.16, ovarian veins (OV) 0.39 +/- 0.13, adrenal veins (AV) 0.85 +/- 0.63; dihydro-T (DHT): PV 0.25 +/- 0.09, OV 0.29 +/- 0.10, AV 0.93 +/- 0.65; delta 4-androstendione (A): PV 0.88 +/- 0.34, OV 1.82 +/- 1.04, AV 9.22 +/- 8.04; DHEA; PV 5.13 +/- 1.96, OV 6.73 +/- 2.69, AV 146.79 +/- 217.24; DS PV 1860 +/- 850, OV 1937 +/- 1039, AV 2567 +/- 1201; 17 alpha-hydroxyprogesterone (17P): PV 0.60 +/- 0.19, OV 1.46 +/- 1.64, AV 6.94 +/- 6.20; F: PV 170 +/- 50, OV 130 +/- 21, AV 788 +/- 1320; the bilateral differences of effluent levels were not significant. Glandular-peripheral vein steroid gradients served as semiquantitative estimates of momentary secretory activity; they were as follows (mean +/- SD; ng/ml) T: ovarian-peripheral vein gradient (OPG) 0.03 +/- 0.09, adrenal-peripheral vein gradient (APG) 0.48 +/- 0.57; DHT: OPG 0.05 +/- 0.05, APG 0.69 +/- 0.60; A: OPG 0.97 +/- 1.13, APG 8.33 +/- 7.86; DHEA: OPG 1.70 +/- 1.80, APG 141.80 +/- 216.60; DS: OPG 191 +/- 72, APG 706 +/- 824; 17P: OPG 0.87 +/- 1.67, APG 6.30 +/- 6.10; F: OPG 38 +/- 11, APG 610 +/- 1329. Gradient, analysis revealed that the ovaries produced significant quantities of A, DHEA and 17P, but no T, DHT or F between day 3-7 of the cycle; direct gonadal DS output was detected in 2 individuals. A significant OPG for DS was detected in two individuals possibly indicating its partially gonadal origin. The adrenals released larger amounts of A, DHEA and 17P than the ovaries at this stage (P less than 0.05); also, they consistently secreted T, DHT, DS and F.

A Sertoli-Leydig cell tumor and pregnancy. Clinical, endocrine, radiologic, and electron microscopic findings

An extremely rare case of a conception occurring in a 26-year-old patient with a small virilizing Sertoli-Leydig cell tumor (diameter: 0.6 cm), bilateral polycystic ovaries and non-tumorous adrenal hyperandrogenism is presented. Prepregnancy findings included hirsutism, clitoromegaly, secondary amenorrhea, and elevated peripheral plasma testosterone (T; 5.7 ng/ml). Extensive basal steroid screening, dynamic function tests, conventional radiologic procedures, selective glandular vein catheterization, and laparoscopy failed to localize unequivocally the source of androgen excess, but suggested bilateral adrenal involvement. The patient conceived during the diagnostic work-up; peripheral T levels increased to 12.1 ng/ml within the first trimester. An exploratory laparotomy with left adrenalectomy, right adrenal biopsy and left ovarian wedge resection revealed an incompletely removed Sertoli-Leydig cell tumor, but normal adrenal histology. The pregnancy was terminated, a left oophorectomy and right ovarian wedge resection were performed at 14 weeks' gestation. Subsequently, peripheral androgens returned to normal, regular menses resumed, and hirsutism disappeared. Three years later the patient delivered a healthy female infant.

Antiandrogens in the treatment of acne and hirsutism

The review discusses (1) the relationship between the endocrine actions of antiandrogens and their therapeutic efficacy and (2) recent chemical and pharmacokinetic data on cyproterone acetate (CPA). It also provides (3) a comparison of CPA and spironolactone regarding the tentative benefits and risks and offers (4) general rules for the drug treatment of androgenized women. Clinical results indicate that those agents are most effective which not only competitively inhibit androgen binding at the receptor level but also suppress androgen secretion and/or production. The combined mode of action is observed with CPA as well as spironolactone. Pharmacokinetic studies underline the necessity to restrict CPA administration in huge doses to the first half of a treatment cycle in order to avoid bleeding disturbances. Also it appears that individual differences in CPA bioavailability do not satisfactorily explain the lack of therapeutic response in about 30% of the cases. Data are presented hinting that the 15 beta-hydroxy-, metabolite of CPA may actually be the biologically active agent. In addition preliminary results are given indicating that intramuscular CPA is therapeutically more effective than oral CPA.

The diagnostic value of plasma free testosterone in non-tumorous and tumorous hyperandrogenism

The clinical significance of total and free testosterone (T) estimates for the diagnostic approach to hirsute patients was assessed. Plasma T was measured by radioimmunoassay and its non-protein-bound fraction was determined by equilibrium dialysis, thus facilitating the calculation of apparent free T (AFT). The cases of 162 subjects were investigated; the subjects included 75 women in whom glandular androgen release had been defined by selective catheterization. A positive linear correlation was observed between both parameters over a wide range of concentrations (T, 153 to 10,700 pg/ml; AFT, 0.8 to 342 pg/ml; P less than 0.001). Significant differences of mean T and AFT levels were found between healthy control subjects (n = 8) and subjects with non-tumorous hyperandrogenism (n = 60; P less than 0.005). Individual values overlapped considerably; elevated T (greater than 640 pg/ml; 48%) or AFT (greater than 7.2 pg/ml; 52%) were present in only half the hirsute women. However, the upper 95% confidence limits of normal for both indices were exceeded in all patients with androgen-secreting ovarian tumors (n = 7). It is concluded that the indirect estimation of AFT in addition to T is time-consuming, costly, without practical value in selecting the proper treatment, and therefore not mandatory in the routine evaluation of androgenized women.

[Treatment of virilized women with intramuscular administration of cyproterone acetate]

Management of hirsutism with high-dose oral cyproterone acetate (CPA) is associated with a failure rate of about 30%. The present investigation analyses the efficacy of parenteral CPA administration in non-tumorous hyperandrogenism. Medium-dose CPA (300 mg) was injected intramuscularly once per month, followed by oral ethinylestradiol (40 micrograms daily) for 21 days in 42 patients (total of 293 treatment cycles). The onset of withdrawal bleeding was 3 to 8 days later. This regimen was used as primary therapy (group A; n = 18) as well as follow-up therapy in low-dose (group B; n = 10) and high-dose oral standard CPA failures (group C; n = 14). The following satisfactory or good response rates were observed in regard to hirsutism: group A 83,5%, group B 100%, group C 57%; seborrhea A and B 100%, C 89%; acne and androgenetic alopecia A and B and C 100%. Clinical side effects occurred in 20 patients; they corresponded in type and frequency to those elicited by the high-dose oral standard medication and resulted in termination of treatment in only 3 patients. Pilot studies regarding the pharmacokinetics of CPA as well as the effects on plasma total and free testosterone and prolactin failed to explain the therapeutic superiority of parenteral CPA (n = 7 women). Still, it may be concluded that intramuscular CPA administration represents a new and highly effective means of managing hirsute females.

Effects of various replacement oestrogens on hepatic transcortin synthesis in climacteric women

The influence of peri-menopausal oestrogen replacement therapy upon protein synthesis in the liver was investigated. Changes in the cortisol-binding capacity of transcortin (TC-BC) were utilized as an indicator of hepatic oestrogen sensitivity. Forty-two climacteric women were studied before and after treatment with various drugs at different doses (patients receiving identical compounds served as their own controls for the evaluation of dosage effects; duration of medication: 14 days at each dose). Oral administration of oestriol (1 and 2 mg daily; n = 6), oestriol (1 and 2 mg daily) + oestradiol-17 beta (2 and 4 mg daily; n = 8), oestradiol valerate (1, 2, 4 and 6 mg daily; n = 6), conjugated equine oestrogens (0.3 and 0.6 mg daily; n = 6), sodium oestrone sulphate (0.8 and 1.6 mg daily) + sodium equilin sulphate (0.2 and 0.4 mg daily; n = 6) and quinoestrol (25 micrograms daily; n = 6) failed to alter TC-BC. However, ingestion of higher doses of conjugated equine oestrogens (0.9 and 1.25 mg daily; n = 5) and quinoestrol (50 micrograms daily; n = 6) caused a significant rise (P less than 0.01). Ethinyloestradiol was given orally as a reference substance and elicited an elevation of expected magnitude. Vaginal administration of dienoestrol cream (1 mg daily; n = 4) did not change TC-BC. These data indicate that the hepatotrophic effects of replacement oestrogens vary depending on the preparation and dosage selected for treatment.

Anti-estrogenic effects of contraceptive progestins on the dynamics of gonadotropin release

The hypophysiotropic effects of ethinylestradiol (EE) alone and in combination with three different progestins at various doses were assessed in 39 normal women. The compounds were given orally for 7 to 21 days. Serum LH and FSH were measured before and after GnRH double stimulation (2 x 25 micrograms i.v. at a two-hour interval); the ratio between second and first response served as an index of gonadotropin-synthesis capacity. Compared to pretreatment early follicular phase controls (LH and FSH ratios of 1.3 and 1.4), administration of 40 and 50 micrograms of EE daily elicited a significant amplification of LH and FSH synthesis (LH ratios of 2.2 and 3.3; FSH ratios of 2.8 and 3.3). By contrast, 80 micrograms of EE daily caused little change. The EE-induced rise of pituitary responsiveness to GnRH could be counteracted by the addition of progestins. The degree of inhibition as dependent on the type and dose of the progestational compound. It is concluded that the standardization GnRH double stimulation technique may serve as a pharmacodynamic model to quantitate the estrogenic and anti-estrogenic effects of contraceptive steroids at the pituitary level.

[Operative complications of laparoscopic tubal sterilization with Bleier clips (author's transl)]

The operative complications of 1613 laparoscopic tubal sterilization with Bleier clips were evaluated in a prospective study at the Stadtkrankenhaus Offenbach/M from March 1978 to July 1981 (1239 interval and 374 postabortal procedures; two-puncture technique under general endotracheal anaesthesia). No major complications requiring laparotomy occurred. Minor intraoperative complications were observed in 8.4% of cases. Clip-related problems were encountered in 1.9% (slight tubal or mesosalpingeal bleeding). Other complications included haemorrhage at the puncture site (2.4%), preperitoneal emphysema (1.8%) and uterine perforation during curettage (1,6%). Technical difficulties were recorded in 8,4% of sterilizations; in 6.6% more than one clip per tube was placed to effect complete tubal occlusion. Adnexal pathology prohibited bilateral clip application in 4 women (0.3%). Postoperative complications were negligible. No pregnancies have yet been reported during a mean follow-up period of 17 months. A successful refertilization procedure was performed on one patient. It is concluded that this technique represents a commendable alternative to convention methods of tubal sterilization due to its low operative morbidity, acceptable contraceptive safety and potential reversibility.

Vaginal administration of ethinylestradiol: effects on ovulation and hepatic transcortin synthesis

Ethinylestradiol (EE) was given vaginally to circumvent the intestinal metabolism and initial liver passage which follow oral intake. This route of administration was chosen in an effort to enhance the antiovulatory potency of EE, while decreasing adverse hepatic reactions. Vaginal tablets containing 20-30 micrograms of EE were taken daily by 7 ovulating volunteers from day 5 to day 25 of the menstrual cycle. The regimen resulted in serum EE levels of 62 +/- 27 pg/ml (mean +/- S.D.) 8-10 hours after insertion. Ovulation was inhibited in 5 women (monophasic basal body temperature curves, serum progesterone levels of 0.9 +/- 1.1 ng/ml during the second half of the treatment cycle). The cortisol-binding capacity of transcortin was significantly elevated in all subjects (52.3 +/- 6.4 micrograms/100 ml; controls 25.7 +/- 2.2 micrograms/100 ml). These findings indicate that intravaginal EE is twice as potent as oral EE in regard to inhibition of ovulation as well as stimulation of the hepatic transcortin synthesis. Vaginal administration apparently increases the bioavailability of EE; it does not facilitate a selective reduction of estrogenic effects upon the liver.

XY gonadal dysgenesis: aberrant testicular differentiation in the presence of H-Y antigen

Six patients with pure nonmosaic 46,XY gonadal dysgenesis (XY GD) and histocompatibility H-Y antigen titers in the normal male range (H-Y+) are presented. Clinical characteristics included a female phenotype, masculine skeletal characteristics, signs of virilization, and primary amenorrhea. All individuals had unambiguous female external genitalia, a hypoplastic uterus, bilateral tubes, and streak gonads. Histomorphologic evaluation of the gonads revealed various abortive testicular and ovarian elements capable of steroid production. Gonadal tumors were found in 4 patients (gonadoblastoma, dysgerminoma, granulosa cell tumor, myxofibroma). Plasma and urinary androgens and basal and stimulated gonadotropin levels were elevated prior to gonadectomy. Data show that the presence of the H-Y antigen per se does not guarantee normal testicular organogenesis. It is hypothesized that defective H-Y antigen binding to its gonadal receptors triggers aberrant testicular differentiation in 46,XY H-Y+ GD.

Medium dose cyproterone acetate (CPA): effects on hormone secretion and on spermatogenesis in men

Medium dose cyproterone acetate (CPA; 10 mg daily p.o.) was administered to 10 fertile men for 12 weeks. Hormonal measurements and semen analyses were performed before, during (4th and 12th week) and after CPA treatment. At the hypothalamo-pituitary level CPA significantly reduced the hypophyseal storage and synthesis capacity for gonadotropins. Basal LH and FSH concentrations were suppressed by 30% and 40%, respectively; while basal prolactin was elevated by 75%. The episodic fluctuations of peripheral gonadotropins remained unaffected. At the testicular level CPA significantly decreased basal testosterone and dihydrotestosterone concentrations by 70% and 50%, respectively. The pulsatile pattern of androgen secretion was abolished. CPA also inhibited spermatogenesis and motility. No serious clinical side effects were observed. All changes appeared to be completely reversible. It is concluded that medium dose CPA induces progestational/anti-gonadotropic effects at the hypothalamo-pituitary level in addition to its antiandrogenic action at the testicular level.