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PubMed1996

[Relationship between cortisol and testosterone during resting conditions, after acute stress and hormone stimulation in steers].

In this study the relationship between peripheral concentrations of cortisol and testosterone was investigated in 7 adult bulls under resting conditions as well as after sexual and hormonal stimulation. The animals were kept under natural photoperiods of 16L:8D and for hormone determinations blood was withdrawn from an indwelling jugular vein catheter every 30 minutes for 24 and 48 h, respectively. Evaluation of the hormonal profiles revealed that both steroids are secreted episodically characterized by irregular, short term fluctuations with high individual variability. A clear circadian rhythm with high levels in the morning and during the day and low concentrations in the evening and during night was observed for cortisol only. Concentrations of both steroidal hormones were not significantly correlated with each other. Intense sexual stimulation (mounting several times with ejaculation) during 30 minutes caused a rapid increase of cortisol without affecting testosterone secretion. After intravenous application of 1500 IU hCG and 0.5 mg GnRH a sharp rise of testosterone concentrations occurred with high values remaining for several hours but leaving the circadian cortisol pattern unchanged. The intravenous injection of 5 mg PGF2 alpha stimulated both the cortisol and testosterone secretion. Results from this investigation show that cortisol and testosterone are secreted episodically without any interrelationship under resting conditions. Sexual stress induced an increase of cortisol which did not inhibit testosterone secretion and high testosterone levels did neither influence the cortisol pattern. The concomitant increase of cortisol and testosterone after PGF2 alpha suggests a central (hypothalamus/hypophysis) action for prostaglandin.

Animals↗
PubMed2003

Insulin-like growth factor I (IGF-I) regulates endocrine activity of the embryonic testis in the mouse.

Insulin-like growth factor I (IGF-I) is important for gonadal and reproductive functions in mammals, although the physiological role of this growth factor during gonadal development in rodents remains largely unknown. Here, we examined the steady-state levels of IGF-I mRNA by the reverse transcriptase polymerase chain reaction (RT-PCR). IGF-I protein expression was also detected by Western blot. The effect of IGF-I as promoter of 17alpha-hydroxylase/C17-20 lyase and 17beta-hydroxysteroid dehydrogenase enzyme activity in vitro was evaluated by radioimmunoassay. Onset of IGF-I gene expression was on day E10 (urogenital ridge stage). IGF-I mRNA expression was markedly reduced on days E12 and E13 (testicular differentiation stage). IGF-I transcripts increased on day E14 and their transcription levels were maintained throughout the stages analyzed. Several IGF-I protein bands of 31-100 kDa were observed. Culture experiments demonstrated that 17alpha-hydroxyprogesterone and testosterone (T) secretion levels increased in the presence of IGF-I on days E11-E17. Additive effects of IGF-I plus (Bu)2cAMP were also seen during testicular development. It is proposed that IGF-I regulates the expression of key steroidogenic enzymes important for endocrine activity of the testis during prenatal development leading to establishment of the male phenotype and fertility.

17-Hydroxysteroid Dehydrogenases↗
PubMed2006

Phytoestrogen action in Leydig cells of Biłgoraj ganders (Anser anser).

The mechanism of phytoestrogen action in gonadal cells of ganders has not been elucidated. The aim of the study was to investigate in Biłgoraj ganders the possibility of phytoestrogen action via estrogen or androgen receptors or via protein tyrosine kinase pathways in Leydig cells. Genistein and daidzein (5 and 50 microM) as well as equol (50 microM) inhibited testosterone (T) secretion by incubated Leydig cells (1x10(5)/ml; 20 h; 37 degrees C). The effects of hydroxytamoxifen (estrogen receptor inhibitor) and cyproterone acetate (androgen receptor antagonist) on phytoestrogen inhibition of T release by Leydig cells were not observed. Lavendustin A (protein tyrosine kinases inhibitor) did not change T production. The influence of phytoestrogens seems not to be conducted via estrogen and androgen receptors or protein tyrosine kinases system in these cells, but further studies are required to completely examine the mechanism of phytoestrogens action in testes of ganders.

Animals↗
PubMed1993

Effect of methoxychlor on ovarian steroidogenesis: role in early pregnancy loss.

Antifertility properties of the pesticide methoxychlor (MXC) are well documented. Administration of MXC to rats during early pregnancy impairs implantation and reduces serum progesterone. The current study was designed to examine the effect of MXC on ovarian steroidogenesis and to define the mechanism(s) by which the pesticide exerts this effect. Rats were treated with MXC at a range of doses during days 1 to 8 of pregnancy and killed on day 9. Ovaries were incubated to assess the secretion of progesterone, estradiol, and testosterone in vitro. Steroid hormones in medium and serum were measured by radioimmunoassay. Although in vivo treatment with MXC reduced serum progesterone, no effect on the ovarian secretion of progesterone was detected in vitro. Conversely, MXC had no effect on serum estradiol levels (testosterone levels were undetectable in serum), but the incubation of ovaries in vitro revealed a reduction in the rates of ovarian estradiol and testosterone secretion.

Abortion, Spontaneous↗
PubMed1979

Steroid secretion by in vitro perfused testes: testosterone biosynthetic pathways.

Alternative metabolic pathways for the biosynthesis of testosterone from pregnenolone exist in mammalian testes. The following experiments were designed to identify the preferred testosterone biosynthetic pathway in rat and rabbit testes. The experimental protocol included the infusion of steroidogenic reaction inhibitors and testosterone biosynthetic intermediates into testes perfused in vitro. Under these conditions, the testicular steroid secretions were a measure of specific reaction activities. Infusion of medrogestone (6,17-dimethyl-4,6-pregnadiene-3,20-dione, Ayerst), an inhibitor of delta5-4isomerization, permitted the reactions converting pregnenolone to androstenediol to be studied separately from those converting progesterone to testosterone. For example, the activity of the pregnenolone vector 17alpha-hydroxypregnenolone reaction was measured as the total of the 17alpha-hydroxypregnenolone, dehydroepiandrosterone, and androstenediol secreted by medrogestone-inhibited testes. The reactions convering delta5-3beta-hydroxysteroids to delta4-3-ketosteroids were studied in testes infused with SU-10603 (7-chloro-3,4-dihydro-2-[3-pyridyl]-1(2H)-naphthalenone. Ciba-Geigy), an inhibitor of 17alpha-hydroxylation and C-17, C-20 cleavage reactions. The results indicated that preferred testosterone biosynthetic pathways are present and different in rat and rabbit testes.

Animals↗
PubMed1989

Effects of FSH and testosterone on highly purified rat Sertoli cells: inhibin alpha-subunit mRNA expression and inhibin secretion are enhanced by FSH but not by testosterone.

The effects of FSH and testosterone on inhibin mRNA expression and inhibin production by highly purified Sertoli cell preparations were examined. Sertoli cells were isolated from testes of 22-day-old rats by sequential trypsin, collagenase and hyaluronidase treatments, with subsequent osmotic shock treatment on day 3 of culture. Contamination by peritubular and germ cells was less than 0.5 and 1-3% respectively. Intracellular and secreted inhibin levels were measured by radioimmunoassay, using Sertoli cells which were incubated for 24 h in the absence or presence of FSH and testosterone from days 4 to 5 of culture. FSH stimulated the cellular inhibin content and the secreted inhibin level by four- and sevenfold respectively, with a half-maximal effective dose of 5-50 ng/ml. Under the present incubation conditions, testosterone (1 mumol/l) had no effect on immunoreactive inhibin levels in either the presence or absence of FSH. Similarly, the expression of inhibin alpha-subunit mRNA was increased following FSH stimulation, whereas testosterone had no effect. The expression of inhibin beta B-subunit mRNAs was not influenced by FSH or testosterone. It is concluded that highly purified Sertoli cell preparations, with a very low number of peritubular or germ cells, are fully responsive to FSH with respect to inhibin mRNA expression and inhibin production.

Animals↗
PubMed1996

Decreases in ovarian cytochrome P450c17 alpha activity and serum free testosterone after reduction of insulin secretion in polycystic ovary syndrome.

BACKGROUND: Insulin resistance and increased ovarian cytochrome P450c17 alpha activity are both features of the polycystic ovary syndrome. P450c17 alpha, which is involved in androgen biosynthesis, has both 17 alpha-hydroxylase and 17,20-lyase activities. Increased activity of this enzyme results in exaggerated conversion of progesterone to 17 alpha-hydroxyprogesterone in response to stimulation by gonadotrophin. We hypothesized that hyperinsulinemia stimulates ovarian P450c17 alpha activity. METHODS: We measured fasting serum steroid concentrations and the response of serum 17 alpha-hydroxyprogesterone to leuprolide, a gonadotrophin-releasing hormone agonist, and performed oral glucose-tolerance tests before and after oral administration of either metformin (500 mg three times daily) or placebo for four to eight weeks in 24 obese women with the polycystic ovary syndrome. RESULTS: In the 11 women given metformin, the mean (+/- SE) area under the serum insulin curve after oral glucose administration decreased from 9303 +/- 1603 to 4982 +/- 911 microU per milliliter per minute (56 +/- 10 to 30 +/- 6 nmol per liter per minute) (P = 0.004). This decrease was associated with a reduction in the basal serum 17 alpha-hydroxyprogesterone concentration from 135 +/- 21 to 66 +/- 7 ng per deciliter (4.1 +/- 0.6 to 2.0 +/- 0.2 nmol per liter) (P = 0.01) and a reduction in the leuprolide-stimulated peak serum 17 alpha-hydroxyprogesterone concentration from 455 +/- 54 to 281 +/- 52 ng per deciliter (13.7 +/- 1.6 to 8.5 +/- 1.6 nmol per liter) (P = 0.01). The serum 17 alpha-hydroxyprogesterone values increased slightly in the placebo group. In the metformin group, the basal serum luteinizing hormone concentration decreased from 8.5 +/- 2.2 to 2.8 +/- 0.5 mlU per milliliter (P = 0.01), the serum free testosterone concentration decreased from 0.34 +/- 0.07 to 0.19 +/- 0.05 ng per deciliter (12 +/- 3 to 7 +/- 2 pmol per liter) (P = 0.009), and the serum sex hormone-binding globulin concentration increased from 0.8 +/- 0.2 to 2.3 +/- 0.6 microgram per deciliter (29 +/- 7 to 80 +/- 21 nmol per liter) (P < 0.001). None of these values changed significantly in the placebo group. CONCLUSIONS: In obese women with the polycystic ovary syndrome, decreasing serum insulin concentrations with metformin reduces ovarian cytochrome P450c17 alpha activity and ameliorates hyperandrogenism.

17-alpha-Hydroxyprogesterone↗
PubMed1980

17 beta-hydroxysteroid dehydrogenase deficiency in malignant interstitial cell carcinoma of the testis.

A partial defect in testosterone (T) secretion due to a 17 beta-hydroxysteroid dehydrogenase deficiency has been documented in a patient with advanced metastatic interstitial cell carcinoma of the testis. Basal serum T was decreased (83 ng/ml), whereas androstenedione was markedly elevated (847 ng/ml). Dehydroepiandrosterone sulfate and estrone were moderately increased, while LH, FSH, and estradiol were minimally increased. After hCG administration, androstenedione rose to much greater degree than T. Fluoxymesterone failed to suppress circulating androgens and estrogens to below basal values, although LH and FSH were suppressed to immeasurable levels. These data support a partial enzyme deficiency within the tumor. They also suggest that although the tumor was autonomous, it still was capable of being stimulated by exogenous gonadotropins.

17-Hydroxysteroid Dehydrogenases↗
PubMed1975

Pituitary-gonadal response to acute I.M. stimulation with clomiphene citrate in normal men.

In order to asses the effect of acute i.m. injection of clomiphene citrate (CC) on LH, FSH, and testosterone (T) secretion, five normal, fertile men received 5 mg of the drug dissolved in 2 ml 0.9% saline, while a further five were injected 10 mg of the same preparation. All tests were performed at 8 a.m. Blood samples were drawn at 0, 30, 60, 120 and 180 minutes of the injection. Serum LH, FSH, and T values were determined by the double antibody radioimmunoassay technique. A significant rise of the LH, FSH, and T levels was obtained in both groups. Peak LH values were obtained at 30 minutes (average), whereas FSH and T peaks occurred at 60 minutes. The 180-minute values were similar to basal. The results seem to indicate that intramsucularly administered CC could be useful, as a rapid test, in evaluating the function of the hypothalamic-pituitary-gonadal axis.

Adult↗
PubMed2000

Effect of chronic administration of an aromatase inhibitor to adult male rats on pituitary and testicular function and fertility.

The aim of the present study was to evaluate the effects of the administration of a potent non-steroidal aromatase inhibitor, anastrozole, on male reproductive function in adult rats. As anastrozole was to be administered via the drinking water, a preliminary study was undertaken in female rats and showed that this route of administration was effective in causing a major decrease in uterine weight (P<0.02). In an initial study in male adult rats, anastrozole (100 mg/l or 400 mg/l) was administered via the drinking water for a period of 9 weeks. Treatment with either dose resulted in a significant increase ( approximately 10%) in testis weight and increase in plasma FSH concentrations (P<0.01) throughout the 9 weeks. Mating was altered in both groups of anastrozole-treated rats, as they failed to produce copulatory plugs. Histological evaluation of the testes from anastrozole-treated rats revealed that spermatogenesis was grossly normal. In a more detailed study, adult rats were treated with 200 mg/l anastrozole via the drinking water for periods ranging from 2 weeks to 1 year. Plasma FSH and testosterone concentrations were increased significantly (P<0.001) during the first 19 weeks of treatment. However, LH concentrations were increased only at 19 weeks (P<0.001) in anastrozole-treated rats, and this coincided with a further increase in circulating and intratesticular testosterone concentrations (P<0.05). No consistent change in inhibin-B concentrations was observed during the study. Suppression of plasma oestradiol concentrations could not be demonstrated in anastrozole-treated animals, but oestradiol concentrations in testicular interstitial fluid were reduced by 18% (P<0.01). Mating was again inhibited by anastrozole treatment, but could be restored by s.c. injection of oestrogen, enabling demonstration that rats treated for 10 weeks or 9 months were still fertile. Testis weight was increased by 19% and 6% after treatment for 19 weeks and 1 year, respectively. Body weight was significantly decreased (P<0.01) by 19 weeks of anastrozole treatment; after 1 year the animals appeared to have less fat as indicated by a 27% decrease in the weight of the gonadal fat pad. The majority of anastrozole-treated animals had testes with normal spermatogenesis but, occasionally, seminiferous tubules showed abnormal loss of germ cells or contained only Sertoli cells. Ten percent of anastrozole-treated animals had testes that appeared to contain only Sertoli cells, and one rat had 'giant' testes in which the tubule lumens were severely dilated. Morphometric analysis of the normal testes at 19 weeks showed no difference in the number of Sertoli cells or germ cells, or the percentage volumes of the seminiferous epithelium, tubule lumens and interstitium between control and anastrozole-treated rats. On the basis of the present findings, oestrogen appears to be involved in the regulation of FSH secretion and testosterone production, and is also essential for normal mating behaviour in male rats. Furthermore, these data suggest that the brain and the hypothalamo-pituitary axis are considerably more susceptible than is the testis to the effects of an aromatase inhibitor. Anastrozole treatment has resulted in a model of brain oestrogen insufficiency.

Anastrozole↗
PubMed1991

Testosterone and avian life histories: the effect of experimentally elevated testosterone on corticosterone and body mass in dark-eyed juncos.

To assess whether alterations in the normal pattern of testosterone (T) secretion might be beneficial or detrimental, we studied a breeding population of dark-eyed juncos in which we elevated T experimentally and measured its effect on potential correlates of fitness. We treated both free-living and captive males with implants that were either empty (C-males, controls) or packed with T (T-males, experimentals). Timing of implant varied and was designed to mimic natural peak breeding levels except that peaks were either prolonged or premature. We bled the birds at recapture and analyzed their plasma, and that of their female mates, for T and corticosterone (B). We also measured body mass and fat score in free-living T- and C-males. In the field, T-implants elevated T and kept it elevated for at least a month. Experimental males also had higher B than controls. In captives, the effect of the implants on plasma T was detectable within 24 hr. B in captive T-males was again higher than in captive C-males. In females, neither T nor B differed between mates of T- and C-males. T-males implanted in early spring lost more mass between implant and recapture in late spring than did controls and also had lower fat scores when recaptured. When implants were inserted in summer, treatment did not influence mass. Elevated T in early spring apparently hastened the transition from the winter to the breeding mode of fat storage. We suggest that prolonged elevation of testosterone might be selected against because of the association between T and B. Premature elevation of T might be costly because of the resultant loss of mass and fat reserves, which could lead to mortality when spring snowstorms prevent access to food.

Adipose Tissue↗
PubMed1999

Alcohol rapidly lowers plasma testosterone levels in the rat: evidence that a neural brain-gonadal pathway may be important for decreased testicular responsiveness to gonadotropin.

Alcohol is reported to suppress testosterone (T) secretion in the adult male rat. Decreases in the circulating levels of luteinizing hormone (LH) and/or the activity of testicular steroidogenic enzymes have been proposed as putative mechanisms underlying this inhibitory effect. We have recently provided functional evidence for a neural pathway between the brain and the male gonads that plays an important role in the ability of brain proinflammatory cytokines to blunt testicular responsiveness to human chorionic gonadotropin (hCG). The present work was designed to test the hypothesis that a similar pathway might be implicated in the inhibitory influence of alcohol on T secretion. Alcohol, administered intraperitoneally or intragastrically, significantly prevented the T response to the gonadotropin. This effect was significant within 15 min of drug treatment. In the intragastric model (the only one used for this type of experiment), the effect of alcohol was not altered by prior blockade of LH release, which suggests that it is independent of changes in the activity of the pituitary gonadotrophs. The lowest effective dose of alcohol, delivered intraperitoneally, was 2.0 g/kg. The intracerebroventricular injection of the alpha- and beta-adrenergic receptor antagonists phentolamine and propranolol significantly reversed the inhibitory influence of alcohol when it was administered 15 min, but not 60 min, before hCG. Collectively, our results indicate that (1) alcohol induces a rapid and profound decrease in plasma T levels that is secondary to decreased testicular responsiveness to hCG; and (2) at least part of this acute inhibitory action of alcohol may depend on the activation of a neural, adrenergic-dependent pathway between the brain and the testes.

Adrenergic Fibers↗
PubMed1975

The role of testosterone in the feedback control of male FSH and LH secretion.

Intramuscular administration of 250 mg testosterone oenanthate per week over a period of 21 weeks treatment rapidly and sustainedly suppressed serum LH as well as FSH levels in seven normal males, while serum testosterone rose by a factor of approximately two. These together with other data provide increasing evidence for a feedback control of FSH secretion by gonadal steroids in the male in addition to the already described but as yet undefined tubular testicular factor.

Adult↗
PubMed1998

Effect of human and murine interferon-alpha on steroid production by rat ovarian cells.

The effect of interferon on the rat ovarian cell function was investigated. Cells from the ovary of juvenile rats were used as a model to investigate the effect of IFN-alpha on the secretion of estradiol and testosterone. In addition the effect of human IFN-alpha (hIFN-alpha) on the secretion of testosterone by the rat adult testis was studied. Present results show that leukocyte hIFN-alpha decreased the human chorionic gonadotropin (hCG) stimulated secretion of estradiol and testosterone by ovarian cells, and the production of testosterone by testis cells. Basal secretion of steroids was affected later and in less proportion than the hCG-dependent production. The IFN-alpha obtained from murine leukocytes, also inhibited the response of ovarian cells to the hCG stimulus.The nature of this effect in the secretion of the steroids is dose and time-dependent. The incubation of hIFN-alpha with an specific antibody completely blocked the effect of the cytokine on ovarian cells.

Animals↗
PubMed1993

Steroidogenic shift by cultured ovarian follicles of Rana dybowskii at breeding season.

The steroid secretory activity of cultured ovarian follicles of Rana dybowskii and the activities of relevant steroidogenic enzymes were examined during the natural hibernation period (October-February). Enzyme activities were measured indirectly by monitoring the conversion of exogenous substrates to products by isolated follicles. Follicles were incubated for 6 h in amphibian Ringer in the presence or absence of frog pituitary homogenate (FPH, 0.1 pituitary/2 ml) and/or various steroid precursors. Progesterone (P4), 17 alpha-hydroxyprogesterone (17 alpha-OHP) or testosterone (T) secreted by the follicles into the medium were measured by RIA. In the presence of FPH, high levels of P4 were produced by follicles at the early and mid-hibernation period (695 and 898 pg/follicle, respectively) whereas markedly elevated levels of P4 were produced during late hibernation (1,393 pg/follicle) (just prior to or breeding season, February). In contrast, high levels of T were produced by the follicles early in hibernation (1,206 pg/follicle) while negligible levels were produced in late hibernation (69 pg/follicle). Higher levels of 17 alpha-OHP were produced by follicles at early and mid hibernation (594 and 705 pg/follicle, respectively) than in later hibernation (221 pg/follicle). Addition of exogenous pregnenolone markedly increased P4 levels in a dose-dependent manner when added to follicles at early and late stages of hibernation: FPH addition further enhanced conversion of pregnenolone. Similarly, addition of androstenedione (AD) increased T levels in a dose-dependent manner by these follicles. However, following addition of exogenous P4, less 17 alpha-OHP was produced by follicles collected in late hibernation as compared to those collected earlier.(ABSTRACT TRUNCATED AT 250 WORDS)

17-alpha-Hydroxyprogesterone↗
PubMed1989

[Prediction of the degree of nocturnal oxygen desaturation in sleep apnea syndrome by estimating the testosterone level].

We studied the influence of hypoxia due to sleep apnea on testosterone (T) secretion. It was conducted on the basis of an idea that sustained hypoxia may depress T secretion. The subjects consisted of 15 male patients with no drug administration whose complaints were snoring and/or obesity. The subjects participated in a sleep study on two consecutive nights. During the first night we collected blood samples starting every 4 hours from 10 PM via a catheter and measured T. From the data of the second night, we calculated total desaturation time with more than 4% from the baseline SaO2. According to the amount of this desaturation time, the subjects were divided into 2 groups; desaturation time less than 80 min in group 1 and longer in group 2, respectively. The peak value was seen at 6 AM in group 1 and at 10 AM in group 2. We investigated the correlation between the ratio of T10/T6, which is the ratio of T level at 10 AM to that at 6 AM, and parameters of sleep disorders related to oxygen desaturation. Total 4% desaturation time in total sleep period and non REM period significantly correlated with this ratio. From the diagram illustrating the correlation between the ratio and total 4% desaturation time in total sleep period, we could assume that if the ratio is beyond 1, the subject may have had more than about 80 min of total 4% desaturation time.

Adult↗
PubMed1990

Effect of pulsatile luteinizing hormone-releasing hormone administration on pituitary-gonadal function in elderly man.

The effect of short-term pulsatile LHRH administration was studied in 8 healthy subjects ranging from 60 to 81 yr to see if the decrease of pituitary gonadal function could be in part due to changes in the discharge of LHRH from the hypothalamus. Gonadotropin and testosterone (T) secretion was evaluated two weeks before and during LHRH (122-160 ng/kg bw every 120 min sc) infusion. In addition, a bolus dosage of LHRH (50 mu iv) was given both at the beginning and at the end of pulsatile LHRH administration in order to test gonadotrophs sensitivity. A significant increase in gonadotropin levels from day 0 to day 4 was found, and was followed by a subsequent decrease from day 7 to day 14. A slight significant increase in T levels was observed during LHRH administration (p less than 0.01). LH pulses were identified in 5 out of 8 subjects on day 0. On day 14, all the exogenous LHRH pulses were followed by significant LH bursts. There was not a significant decrease in the pituitary LH responsiveness to LHRH test from day 0 to day 14. Our study seems to indicate that pituitary - gonadal unit in normal elderly men can be modulated by pulsatile administration of LHRH. A pulse frequency of LHRH which is probably similar to the physiological one, could induce a slight increase in T levels via qualitative changes in LH activity. We can assume that clinical changes in gonadal activity might also be connected to some disturbances in endogenous LHRH pulsar.

Aged↗
PubMed1990

Testosterone and sexual behavior in oral contraceptive users and nonusers: a prospective study.

The relationship between plasma testosterone (T) secretion and patterns of sexual behavior was examined in 18 women using oral contraceptives (OCs) and 13 nonusers matched for partner availability. Retrospective assessments of perimenstrual symptoms, sexual attitudes, and sexual experience were obtained and women completed daily ratings of the frequency of sexual activities and the level of well-being for 1 month. Plasma levels of sex hormone binding globulin (SHBG), progesterone, Total T, Free T, and non-SHBG bound T were determined by radioimmunoassay at four phases of the pill or menstrual cycle. Overall, women not using OCs had higher plasma levels of Total, Free, and non-SHBG bound T and lower plasma levels of SHBG than those of OC users. Further, only nonusers had perimenstrual decreases in plasma levels of Total and Free T. The two groups were comparable on most retrospective measures. However, OC users reported more satisfaction with their sexual partners than did nonusers and prospective monitoring revealed that they engaged in sexual interactions more frequently than did nonusers across the cycle. In contrast, both groups reported a similar frequency of autosexual activities across the cycle. There were no correlations between average levels of T and levels of sexual desire, sexual interactions, or autosexuality. Moreover, only nonusers reported a decrease in levels of sexual desire during the perimenstrual period that was associated with the changes in Free T over the menstrual cycle.

Adolescent↗