Investigation of the influence of two low-dose monophasic oral contraceptives containing 20 micrograms ethinylestradiol/75 micrograms gestodene and 30 micrograms ethinylestradiol/75 micrograms gestodene, on lipid metabolism in an open randomized trial.

An open comparison at a single center was performed in volunteers (n = 58) randomly allocated to two treatment groups, one receiving tablets containing 20 micrograms ethinylestradiol (EE) + 75 micrograms gestodene, and the other 30 micrograms EE + 75 micrograms gestodene. The study consisted of three treatment-free pre-cycles, followed by thirteen 28-day treatment cycles. Analysis of results revealed that there were no statistically significant differences between the two groups with regard to the plasma levels of HDL-cholesterol and its subfractions, LDL-cholesterol and apolipoproteins. There was, however, a trend toward a more favorable effect on HDL-cholesterol in the 20 micrograms EE group, where levels increased by 3% compared with the 30 micrograms EE group, where levels decreased by 9%. There was a statistically significant difference between the adjusted mean values of total triglycerides in the two groups in favor of the 20 micrograms EE group (+21%), compared with the 30 micrograms EE group (+64%) (p = 0.029). Two serious adverse events were reported (lymphadenopathy and vertigo), but neither were considered to be causally related to either study medication. The formulation containing 75 micrograms gestodene and 20 micrograms EE was shown to be a reliable and well tolerated oral contraceptive, with a favorable lipid profile.

The antibodies causing thyroid stimulating hormone-binding inhibition (TSH-BI) are not responsible for the specific inhibition of gonadal steroidogenesis by Graves' sera.

Graves' disease is attributed to the presence of autoantibodies with agonist activity which interact with the TSH receptor causing thyroid hyperstimulation and hyperthyroidism. The degree of TSH-binding inhibition (TSH-BI) caused by a Graves' serum in a TSH radioligand receptor assay is considered to be an index of the prevalence of anti-TSH receptor autoantibodies in that serum. We have previously shown that the specific inhibition by Graves' serum of hCG-stimulated steroidogenesis by Leydig cells was at a site distal to receptor binding and second messenger activation. In this report, we have investigated whether the effect of Graves' serum upon Leydig cells is a property of the constitutive antibodies. Immunoglobulin-enriched fractions were obtained from Graves' and normal sera using three increasingly rigorous procedures; ammonium sulphate precipitation, caprylic acid treatment and Protein A or G-affinity purification. The TSH-BI was determined for untreated and extracted sera in two radioreceptor assays developed for use with serum, one using human thyroid membranes and the other using HeLa cells transfected with the human TSH receptor, and the results were compared with effects in the Leydig cell steroidogenesis bioassay. The specific inhibition of hCG-stimulated Leydig cell steroidogenesis by Graves' sera was not retained in the antibody fraction causing TSH-BI. Thus, the inhibitory factor appears not to be an antibody and we are now attempting to purify and identify the responsible factor from Graves' serum.

Epitope mapping of a recombinant human TSH receptor extracellular domain: identification of a predominant epitope using animal sera.

The extracellular domain of the TSH receptor (TSHR-561, amino acids #78-389) was expressed as a hexa-histidine fusion protein in bacteria. The recombinant protein was purified to homogeneity and used to immunize porcine and ovine species. High titre antibodies were obtained from both species that recognized the recombinant protein in Western blot analysis but failed to interfere with the TSH radio receptor assay. An epitope library was constructed and screened with affinity purified ovine and porcine antisera and detected a number of positive clones. Sequence analysis revealed that all of the epitopes contained sequences derived from the carboxyl terminus of the recombinant immunogen. One clone defined an epitope covering 16 amino acids from the carboxyl terminus and was the common epitope found in all of the other clones. Western blot screening of a large panel of Graves' sera with recombinant TSH receptor protein identified one patient sera that also recognized linear epitopes in the TSHR-561 protein. Experimentation demonstrated that the linear epitope recognized by this human sera was identical to the sequence recognised by the animal antisera. This sequence is unique to the TSH receptor and will be useful in further studies to analyze the TSH receptor protein.

Autoreactive epitopes within the human alpha-enolase and their recognition by sera from patients with endometriosis.

Patients with endometriosis significantly develop autoantibodies directed against endometrial proteins, which may be involved in the aetiology of this gynaecological disease. Based on standard Western blot analysis, a 48 kDa protein was localized in the soluble protein extract of endometrial adenocarcinoma cells using sera from patients with clinically staged endometriosis and identified as the glycolytic enzyme alpha-enolase. The corresponding cDNA coding for the human alpha-enolase was isolated from a human endometrial cDNA library and cloned into the vector pH6EX3, allowing the efficient expression of recombinant human alpha-enolase with an N-terminal histidine-hexapeptide as affinity ligand in Escherichia coli. The purified recombinant human alpha-enolase was evaluated as a specific antigenic tool for the diagnostic measurement of antiendometrial antibodies in sera from patients with endometriosis. With selected endometriosis sera, two linear autoreactive epitopes were localized within the recombinant human alpha-enolase using epitope mapping techniques, and they were characterized.

Human seminal fluid contains significant quantities of prorenin: its correlation with the sperm density.

The relevance of the tissue prorenin-renin-angiotensin system (PRAS) to male reproduction has been suggested by several investigators in the past. Although the presence of angiotensin converting enzyme in semen has been demonstrated, unequivocal evidence for the presence of prorenin and renin in the semen is not yet available. We have used a specific immunoradiometric assay based on an antibody directed against the pro-segment of the prorenin molecule to demonstrate that significant quantities of prorenin are present in human semen samples. Although semen is a rich source of proteases and protease inhibitors, the assay used by us, unlike the usual enzymatic renin assay, is not affected by such proteases, and their inhibitors. Furthermore, Western blotting data clearly demonstrated that prorenin is present in semen as a 48 kDa protein. In a majority of semen samples, the prorenin content was found to be several fold greater than that measured in EDTA-plasma samples. Interestingly, the level of prorenin was found to be directly proportional to the sperm density in semen samples. Our results suggest that seminal prorenin is produced locally within the male reproductive system, although its exact origin is yet to be defined, that a complete prorenin-renin-angiotensin system exists in human semen and that this system may be relevant to sperm function.

24-hour profiles of salivary progesterone.

OBJECTIVES: To assess whether the known pulsatility of P secretion by the corpus luteum, which is detected in blood by P measurements, translates into fluctuations of saliva P concentrations, and to determine how well saliva P measurements reflect plasma P concentration. A second objective was to see whether there is a window in the luteal phase, where P secretion has reached its maximum capacity, but the amplitude is not very accentuated, which would be an ideal time to measure P. DESIGN: Twenty-one ovulatory women were randomly assigned to be studied on day 5, 7, or 8 after the luteinizing hormone surge. Blood samples were drawn every 20 minutes, and saliva samples were obtained hourly over a 24-hour period. Comparison between saliva plasma P was performed, and pulse analysis of plasma P was done. RESULTS: The percent variation of saliva P concentration over a 24-hour period was much higher when compared with the percent variation of plasma P concentration over the same time period (saliva P: 149%; plasma P: 107%). Also, the ratio of saliva to plasma P varied significantly between individuals (range: 0.0050 to 0.0148). A single plasma P concentration (8:00 A.M.) correlated better with the 24-hour mean plasma concentration than the respective single saliva value or the mean of two or three saliva samples (8:00 A.M. and 12:00 P.M.; 8:00 A.M., 12:00 P.M., and 8:00 P.M.). Plasma pulse frequency, mean pulse interval, pulse width, pulse amplitude, and 24-hour mean P level did not differ between the 3 study days. CONCLUSIONS: A single plasma P determination reflects more accurately 24-hour P secretion than repeated saliva P samples measured in the same individual. We could not identify a window in the luteal phase when P measurements are more representative of corpus luteum function.

Serum unmasks the binding of thyroid-stimulating hormone to endogenous and transfected receptors: evidence for a soluble form of the receptor in human thyroid.

A specific homologous radioligand receptor assay for thyroid-stimulating hormone (TSH) using bovine thyroid membranes was adapted for use with human thyroid. Specific 125I-labelled TSH binding was detected in the 3000 g membrane pellet from bovine thyroid but predominantly in the 3000 g supernatant of the human thyroid homogenate. Both assays required incubation in the presence of 10% serum, whilst the assay using human thyroid could only be precipitated using polyethylene glycol (PEG). The serum requirement transcended a possible role as carrier protein and unmasked specific TSH binding. Molecular sieving determined that the active fraction of the serum had an apparent size of 30,000-100,000. The requirement for PEG-assisted precipitation of the TSH receptor assay was a consequence of the TSH-binding entity from Graves' thyroid behaving like a soluble 'receptor': it did not sediment with the membranes, passed a 0.2 microns filter and, upon molecular sieving, had an apparent size of 300,000-1,000,000. A full-length TSH receptor cDNA was cloned from a human Graves' thyroid library and stably transfected cell lines expressing the TSH-receptor protein were constructed using human HeLa and murine 3T3 cells. Specific TSH binding was unmasked by serum in the human cell lines, as observed for the human thyroid TSH receptor, whereas serum hindered TSH binding in the murine cell lines. A soluble form of the receptor was not released from the cells and was not produced in conditions which demonstrated a soluble receptor-like binding component in human thyroid tissue.

Graves' autoimmune serum inhibits gonadal steroidogenesis: development of a Leydig cell bioassay to identify broad spectrum anti-endocrine autoantibodies.

In order to establish an assay for the detection of autoimmune sera with broad spectrum activity, we have investigated the effect of unselected normal and Graves' disease sera upon steroidogenesis by gonadal cells. Steroidogenesis was enhanced by the addition of normal serum in a 3-h primary Leydig cell bioassay, but was inhibited by the majority of Graves' sera. The inhibition was not related to clinical thyroid parameters, such as the severity of the TSH-binding inhibition index, and was not overcome by other agonists or second messenger supplements. Although pituitary TSH preparations bound to and stimulated Leydig cells, TSH receptor mRNA was not detectable and pure recombinant TSH failed to bind or stimulate, indicating contamination of pituitary TSH with LH. The binding of hCG to the Leydig cell luteinizing hormone receptor was not perturbed by the Graves' autoimmune sera, indicating that cross-reactive anti-TSH receptor antibodies were not responsible for the inhibition. By use of intermediates in the stimulatory pathway, the site of Graves' serum inhibition was identified to be distal to hormone receptor/adenylate cyclase coupled responses and proximal to supply of cholesterol for steroidogenesis.

A direct immunoradiometric assay for human plasma prorenin: concentrations in cycling women and in women taking oral contraceptives.

Two synthetic penta deca peptides corresponding to the N-terminal portion (amino acid sequence 1-15) and the C-terminal portion (sequence 32-46) of the pro moiety of the human prorenin (PR) molecule were coupled to BSA and used as antigens to generate antibodies against PR. In a RIA system using the 125I-labeled peptide as tracer, it could be shown that antibodies against peptide 32-46 bound the peptide and the native PR in the follicular fluid (FF) to a similar degree, whereas antibodies generated against peptide 1-15 did not specifically recognize native PR. The specificity of the PR-(32-46) antibodies for PR was demonstrated by comparative measurements of PR by RIA and by an indirect procedure (involving trypsin treatment of PR) in different individual FF samples, plasma samples, and fractions of FF obtained by gel filtration or immunoaffinity chromatography. Normal plasma PR levels could not be measured by RIA, since they were below the detection limit of the assay (0.5 micrograms PR/L approximately 10 pmol/L). For measurement of the low PR levels in plasma, a sensitive direct immunoradiometric assay with a detection limit of 0.1 fmol PR/tube was developed. It was based on the combined action of a commercially available solid phase renin antibody and the affinity-purified and 125I-labeled PR-(32-46) antibody. The measurement of 35 individual plasma samples with different PR concentrations showed an excellent correlation (r = 0.99) between the new direct and the conventional indirect assays. The direct assay of PR concentrations in plasma of healthy women during the length of a menstrual cycle resulted in a biphasic pattern of PR concentrations, with peak levels (approximately 3-fold increase) at the time of the LH surge. The intake of monophasic and triphasic contraceptives caused a suppression of normal PR concentrations (96.9 +/- 34 ng/L; early follicular phase; n = 12) by 39% and 25%, respectively, which was also observed in the pill-free phase of the artificial cycle.

PIP: This paper studies the effects of different oral contraceptives on plasma prorenin (PR) levels in women as determined by a direct immunoradiometric assay (IRMA). 3 healthy and normally cycling women, aged 22, 30, and 37, volunteered for venipuncture every second day of one complete menstrual cycle. 18 healthy women taking oral contraceptives were studied for the effects of oral contraception on plasma PR concentrations. Results of this study showed that in a renin-angiotensin (RIA) system, using the I-labeled peptide, antibodies against peptide 32-46 bound the peptide and the native PR in the follicular fluid (FF) to a similar degree, while antibodies generated against peptide 1-15 did not recognize native PR. The absolute PR levels measured by the direct assay were approximately 20% lower than in the indirect assay, although both assay procedures indicate the same molecular measurement. The measurement of the different PR concentrations of the 35 individual plasma samples indicates an excellent correlation (r = 0.99) between the new direct and the conventional indirect assays. Sequential changes in the plasma PR levels of healthy women demonstrate that PR in the circulation was mainly due to ovarian origin. Lastly, PR concentration was significantly lower at any time during the artificial cycle than in the early follicular phase of spontaneous cycles. In conclusion, this PR IRMA is believed to be superior to the conventional indirect procedures.

The relationship between prorenin levels in follicular fluid and follicular atresia in bovine ovaries.

Bovine follicles having a higher concentration of progesterone than estradiol in the follicular fluid can be considered as atretic. Since we observed previously that there was an inverse relationship between the follicular fluid estradiol to progesterone (E/P) ratio and the prorenin level, we have proposed that a high prorenin level may be associated with follicular atresia. The aim of the present study was to corroborate this hypothesis by including additional indices to distinguish unambiguously between atretic and nonatretic follicles and to compare the prorenin levels in these two groups of follicles. The present study included examination of more than 200 follicles in the follicular fluid of which we have measured steroid and prorenin levels. The results obtained show a highly significant negative correlation between the prorenin level on the one hand and the E/P ratio, estrogen to total androgen ratio, or estradiol concentration on the other hand. As a further criterion for atresia, we have examined the histological characteristics of the follicles by light and electron microscopy and have found that 90% of histologically characterized atretic follicles had an E/P ratio less than 1 and an average prorenin level four to five times higher than nonatretic follicles. Finally, when we determined the FSH-stimulated cAMP response and the aromatase activity, in terms of the ability to convert exogenous androgen to estrogen in granulosa cells isolated from individual follicles, we observed a markedly higher prorenin level in the fluid of follicles whose granulosa cells responded poorly to FSH and showed a low aromatase activity, compared to follicles whose granulosa cells responded strongly to FSH and contained high aromatase activity. In summary, follicles that were classified as atretic on the basis of a number of biochemical and histological parameters contained significantly higher prorenin levels in their follicular fluid than nonatretic ones. Thus, a high follicular fluid prorenin level is a valid indicator for follicular atresia in bovine ovaries. However, the reason for this increase in follicular fluid prorenin level and whether this increase is a cause or a consequence of atresia remains to be determined.

[Rational hormone diagnosis in normocyclic functional sterility]. / Rationelle hormonale Diagnostik der normozyklischen funktionellen Sterilität.

Functional infertility in women with a normal menstrual cycle is the first symptom of a pathophysiological sequence of multiple different endocrinopathies. It usually progresses and leads to secondary amenorrhoea which is the most severe symptom of ovarian insufficiency. The percentage of abnormal hormonal parameters will increase with the duration and extent of the endocrinological aberration. The aim of this study is to examine the frequency of the different potential changes in hormone levels of an unselected group of female patients in a fertility clinic. 307 patients suffering from functional sterility (menstrual cycle 25-34 days) were investigated via basal hormone laboratory tests (including TRH test) under standardised conditions. 73 patients had pathological changes of the Fallopian tubes and in 116 patients their husbands had severe andrological problems. Excluded from this study were patients with bilateral occlusion of the Fallopian tubes and patients whose partners had a sperm count of less than 1 million/ml. The percentage of abnormal hormone levels (greater than mean + standard deviation + grey area) was 32.2% for prolactin (PRL), 7.8% for TSH, 20.9% for Delta-TSH, 18.4% for DHEA-sulfate (DS), 9.8% for testosterone (T), 18.9% for LH, and 11.5% for FSH (LH and FSH were specifically calculated only in 87 patients). In 65.5% of the patients the midluteal oestradiol (E2) and progesterone (P) levels were below normal, as sign of a corpus luteum insufficiency (CLI). A step- by-step diagnostic procedure would have yielded the following cumulative abnormal hormone levels retrospectively: (1) PRL (n = 99) = 32.2% (2) +TSH/delta TSH (n = 85) = 48.9% (3) +DS (n = 56) = 58.0% (4) +T (n = 30) = 59.3% (5) +LH/FSH (n = 28) = 62.2% [(6) +E2/P (n = 201) = 82.7%.] Only in 37.8% (116 patients) all hormone levels were within normal limits during the early follicular phase (FP); if the patients with signs of CLI are added, the percentage would be only 17.8% (n = 53). Case analysis demonstrated that functional sterility was accompanied by hyperprolactaemia in 32.4% of all patients, by abnormalities of the thyroid function (hypothyroidism 16.0%, hyperthyroidism 7.8%) in 23.8%, by hypothalamic and/or pituitary dysfunction in 28.7%, and by hyperandrogenaemia in 22.5%. Primary ovarian insufficiency was diagnosed in 4.6%. 31.3% of all patients (n = 307) had a combination of different hormonal abnormalities. The average duration of infertility among this group of patients was 6.3 years.(ABSTRACT TRUNCATED AT 400 WORDS)

Histones inhibit human chorionic gonadotrophin-stimulated but not atrial peptide-stimulated testosterone production and cyclic nucleotide formation by isolated mouse Leydig cells.

Recently it has been reported that histone type H2A can inhibit gonadotrophin-stimulated cAMP formation and steroidogenesis by ovarian cells. In the present study we have investigated if similar antigonadotrophic effects of commercially available histones can also be demonstrated on testicular steroidogenic cells. Using percoll-purified mouse Leydig cells, we have demonstrated that several types of histones could almost completely inhibit hCG-stimulated testosterone production and cAMP formation. The inhibition was dose-dependent and could be reversed by the addition of excess of hCG. The most potent histone types were H2AS and H8S, both of which could inhibit hCG-stimulated cAMP formation half-maximally at concentrations of 4-5 micrograms/ml. Forskolin-stimulated cAMP formation was not affected by histones. When the cells were stimulated with either db-cAMP or rAP-II, histone H2AS and H8S failed to inhibit the testosterone production. In fact there was a marked increase in the amount of testosterone produced, the reason for which is not yet understood. The amount of cGMP accumulated in response to rAP-II was not affected by the presence of H2AS or H8S. In unstimulated cells, neither the cyclic nucleotide level nor the amount of steroid produced was affected by the histones. Based on the [125I]hCG binding data it is possible to conclude that histone H2AS inhibits the binding of hCG to its receptors on Leydig cells and thereby causes the inhibition of hCG-stimulated cAMP formation and steroidogenesis.

[Endocrinological diagnosis of normocyclic functional sterility]. / Endokrinologische Diagnostik der normozyklischen funktionellen Sterilität.

Normocyclic functional sterility can be regarded as a starting point to the common pathophysiology of different endocrinopathies. Those are finally leading to secondary amenorrhoea, as the most severe sign of ovarian insufficiency. The incidence of abnormal hormonal parameter increases parallel to the duration and the extent of the respective endocrinopathy. For a better causal classification of the endocrine disorder a complete hormonal assessment is mandatory, as characteristic historical data or significant clinical signs will often be missed in infertile patients. The completion of one single basic hormonal examination might lead to an exact differentiated diagnosis and then allows accordingly for the induction of a purposeful treatment. The pregnancy rates are considerably high proving the effectiveness of the thoughtful pretherapeutic diagnostic evaluation. The principle of cost-effectiveness is as well maintained by the follow-up of complete diagnosis and master-tailored therapy.

Influence of melatonin on the sleep-independent component of prolactin secretion.

Sleep has a stimulatory effect on prolactin secretion. Recent studies in the human suggest the hypothesis that prolactin has also an endogenous sleep-independent rhythm, which can be influenced by endogenous melatonin. To investigate this hypothesis, the prolactin response to nighttime exposure to bright light was studied in eight women in detail. Light exposure induces a decrease in nocturnal melatonin secretion. It was demonstrated that exposure to bright light for 2 h at night caused a decrease in prolactin secretion, which surpassed significantly the decline one would expect by sleep deprivation only (P less than 0.01). This was associated with a similar decline in melatonin secretion. Fall and rise of prolactin secretion under these conditions were always preceded by decrease and rise in melatonin levels in all eight women studied. Based on these observations, it is concluded that melatonin is associated with an endogenous circadian component of prolactin secretion. As specific melatonin receptors have been identified in the human nucleus suprachiasmaticus, which is the "master" circadian pacemaker, the observed phenomenon might be mediated through this structure. An alternative explanation of our findings could be based on the fact that melatonin influences dopamine metabolism, which in turn alters prolactin secretion. It can also not be ruled out that melatonin might act via the opioid system, which then could affect prolactin secretion. The total secretory activity for both hormones (area under the curve) did not change under experimental conditions, when compared to a control group. This suggests that acute light exposure and sleep deprivation influence the secretory process rather than the synthesis of these two hormones. This is in agreement with the observation that changes in natural light exposure throughout the year do alter the amplitude, but not the total amount of melatonin secreted. Further studies are needed to answer the question of melatonin storage definitively, as it is commonly believed that melatonin is immediately released after synthesis. It is concluded that melatonin through its external modulator light might entrain the circadian sleep-independent component of prolactin secretion and via its action on prolactin could modulate reproductive processes.

Circadian variations in plasma melatonin, FSH, LH, and prolactin and testosterone levels in infertile men.

Circadian patterns of plasma melatonin, FSH, LH, prolactin, and testosterone were studied in 10 healthy men, 20 men with oligozoospermia, and 8 men with azoospermia. Circadian rhythms were found in concentrations of melatonin and prolactin, with higher values at night in comparison with daytime levels. In patients with oligozoospermia and azoospermia an elevation in melatonin levels was observed, and an increase in melatonin concentrations occurred before onset of darkness (i.e., at 2000 h). Levels of FSH, LH, and prolactin were elevated in infertile patients. The possibilities that an increase in melatonin concentrations is either the primary feature that leads to the regression of the seminiferous epithelium or is secondary and depends on elevated gonadotropins and/or prolactin levels are discussed.

Functionally distinct agonist and receptor-binding regions in human chorionic gonadotropin. Development of a tertiary structure model.

The histidine residues in human chorionic gonadotropin (hCG) were chemically modified using diethyl pyrocarbonate. Derivatives of hCG with an average of 0.5-3.5 histidines modified (maximum of 4 per hCG) had reduced receptor-binding and cell-stimulating activities. Acylation of hCG at progressively lower pH values (conditions in which 1 of the 2 absolutely conserved histidines alpha His-83 is not titratable, whereas alpha His-94 becomes increasingly protonated and resistant to modification) produced hCG derivatives with a greater retention of receptor-binding activity than cell-stimulating activity. The involvement of alpha His-94 as part of the receptor-binding region of the hormone and of alpha His-83 as a putative active site residue was inferred. Proteinaceous protease inhibitors were shown to neutralize the agonist activity of hCG and to reduce the binding of hCG to its receptor and also to specific antisera. It was presumed that an inhibitor-hormone complex was formed which was analogous to the complexing of inhibitor with the "substrate pocket" of a serine protease. The discovery of primary sequence analogies between hCG and the serine protease chymotrypsin enabled the prediction of hCG structure using the enzyme as a folding template. Solvent-exposed and buried core regions of the peptide chain were delineated using smoothed hydrophobicity profiles in combination with Chou-Fasman secondary structure predictions. Hypervariable hydrophobicity indices between residues 38 and 80 of the human beta subunits reflected different folding arrangements which presumably conferred the individual receptor specificities. When mapped to the putative structure these receptor-determinant loops were adjacent to an area of the alpha subunit analogous to the substrate pocket of serine proteases. Disulfide bond assignments and intersubunit contact regions were identifiable. The proposed tertiary structure for hCG manifests the topographical epitopes defined using monoclonal antibodies and satisfies the currently available data on specific modification and its effects upon hormonal structure and function. This paper is considered to be the first report of a differential effect upon the agonist and receptor binding abilities of a glycoprotein hormone after modification of the proteinaceous, as opposed to the glycosylated, moiety of the molecule.

[Rational hormonal diagnosis of oligomenorrhea]. / Rationelle hormonale Diagnostik der Oligomenorrhö.

In a study, conducted by two clinics in Berlin and Hamburg, specializing in reproductive endocrinology, the anamnestic, clinical, and laboratory data of 170 oligomenorrheic patients (menstrual intervals between 35 and 90 days) were evaluated in order to determine the frequency of possible causes of oligomenorrhea. Pathological hormone levels were found in two thirds of all patients. The order of frequency of abnormal hormone levels was as follows: hyperandrogenemia (testosterone and/or DHEA-sulfate) in 41.8%, hyperprolactinemia in 25.9%, abnormal thyroid function (TSH and/or TRH-induced TSH) in 21.7%, and hypergonadotropic FSH levels in 3.5% of all patients. There was an overlap of between two or more pathological conditions in one third of all patients. This study confirms results of a previous study in amenorrheic patients (Moltz et al., 1987 - see reference list), documenting hyperandrogenemia as the most frequent abnormality found in this group, followed by hyperprolactinemia. As can be expected, the percentage of women with no discernible abnormality was higher in oligomenorrheic patients when compared with the amenorrheic group (32.3% vs 7.7%). Furthermore, overweight patients were overrepresented in the oligomenorrheic group, while underweight patients were seen more frequently in the amenorrheic group. In view of these results of our study we recommend a detailed diagnostic follow-up in all younger patients with ovarian disorders who need to preserve their reproductive potential. This follow-up should include hyperprolactinemia, hypo-/hyperthyroidism, hyperandrogenemic and hypoestrogenemic states and exclusion of primary ovarian failure. In contrast to recommendations of WHO, issued in 1976, such diagnostic work allows an etiology oriented therapy decision and a therapy risk assessment in subgroups of patients, such as hyperandrogenemic patients, who receive clomiphene or gonadotropin treatment. Furthermore, it permits prophylactic considerations, for prevention of hirsutism and polycystic ovarian disease, struma and osteoporosis prophylaxis.