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PubMed1992

Prevalence of seasonal affective disorder in Alaska.

OBJECTIVE: The goals of this study are to provide estimates of the prevalence of seasonal affective disorder in Alaska, to examine sociodemographic correlates, and to evaluate the relation between seasonal affective disorder and general depression. METHOD: A random sample of 283 residents of Fairbanks who had lived in Alaska for 3 years or more were interviewed with the Seasonal Pattern Assessment Questionnaire and the Center for Epidemiologic Studies Depression Scale (CES-D Scale). RESULTS: Twenty-six (9.2%) of the subjects met diagnostic criteria for seasonal affective disorder, one of the highest figures yet reported. These cyclic winter affective disorders occurred more often in women than men (ratio = 3:2) and were less prevalent among residents who were older than 40 years of age. Assessment of depression with the CES-D Scale supported the diagnostic classification of respondents and the differentiation of seasonal affective disorder from other depression. CONCLUSIONS: This study supports the conclusions that seasonal affective disorder is prevalent in northern populations and that sex and age may represent the major risk factors that differentiate it from the general experience of depression in northern communities.

Adult↗

PubMed1997

Seasonal variation in the occurrence of homicide in Finland.

OBJECTIVE: Although seasonal variation in impulsive aggression related to circannual rhythms of central serotonin neurotransmission is a topic of current interest, there is little firm knowledge on seasonality in the occurrence of homicide. Longitudinal studies on the seasonal rhythms of platelet imipramine binding and L-tryptophan levels have placed the circannual peaks around January and February and the nadirs around May and August. The aim of this study was to test the hypothesis that the number of homicides is the lowest during winter and the highest during spring and summer. A secondary hypothesis was that the seasonal variations in homicides and violent suicides are correlated. METHOD: The largest database on the monthly occurrence of homicide thus far (N = 4,553) was used in this study, in which the monthly occurrence of all murders and manslaughters in Finland during the years 1957-1995 was analyzed. RESULTS: During winter the homicide rate was 6% below the expected rate. Correspondingly, during summer there was a 6% elevation above the expected homicide rate, but no significant peak was observed in spring. There was a significant association between the monthly occurrence of homicides and violent suicides but not between homicides and nonviolent suicides. CONCLUSIONS: The results suggest that a seasonal variation in the occurrence of homicide exists. On the basis of current literature, it could be hypothesized that this seasonal variation and the correlation between the monthly occurrence of homicides and violent suicides are associated with the observed circannual rhythms of serotonin transmission.

Biomarkers↗

PubMed2003

Seasonal variations of chronic hemodialysis dose in South Croatia.

INTRODUCTION: The dialysis parameters are used for prescribing the dose of dialysis therapy. Delivered dialysis dose could be calculated from predialysis and postdialysis blood urea concentrations. Seasonal variations in some clinical and laboratory variables occur among chronic hemodialysis patients. Seasonal variations in chronic hemodialysis dose have not been investigated. We prospectively compared hemodialysis adequacy parameters in order to demonstrate its seasonal differences. SUBJECTS AND METHODS: Data were processed on 201 single dialysis treatments involving a group of 51 anuric chronic hemodialysis patients. The study period was 12 months. Four measurements per subject were obtained (in January, April, July, and October). RESULTS: We could not demonstrate seasonal variability in prescribed and delivered hemodialysis dose, in "delta" values (absolute differences between prescribed and delivered dialysis doses for the same hemodialysis treatment), or in ultrafiltration per hemodialysis. Seasonal differences were found in blood urea concentrations before and after hemodialysis (p = 0.001, p = 0.010). When the data were grouped into two groups: cold (January and October) and mild (April and July) months; we could not demonstrate significant differences in dialysis adequacy parameters, but there were differences in blood urea concentration before hemodialysis (26.06 +/- 14.73 vs. 24.35 +/- 4.50, p = 0.004), blood urea concentration alter hemodialysis (10.24 +/- 2.96 vs. 9.43 +/- 2.60, p = 0.019), and ultrafiltration per hemodialysis (3.36 +/- 1.13 vs. 3.10 +/- 1.11, p = 0.046). CONCLUSION: Based of the results of this investigation conducted on chronically hemodialyzed patients in the mild Mediterranean climate in South Croatia, Europe; we have concluded that clinicians should not pay attention to season when they prescribe hemodialysis dose or analyze delivered hemodialysis dose.

Anuria↗

PubMed1992

Seasonality in psychiatry--a review.

This paper reviews the literature pertaining to seasonal patterns in psychiatric illnesses. Evidence on the season of birth phenomenon suggests that a greater risk of pre-, peri-, or post-natal damage is associated with the winter months. There is currently insufficient evidence to pinpoint the exact mechanism involved or to ascertain whether the mechanism is common to each condition. Studies of seasonal patterns of incidence of psychiatric disorders have highlighted the role of seasonally regulated environmental factors on internal biological processes. There is growing evidence that serotonin is involved in a variety of psychiatric disorders. Seasonal patterns have been observed in processes involving serotonergic functioning. Furthermore, it has been postulated that these processes may be influenced by photoperiod, suggesting that the seasonal patterns of incidence of several psychiatric conditions may share a common neurophysiological substrate.

Female↗

PubMed1997

Melatonin and seasonal rhythms.

The pineal hormone melatonin plays a ubiquitous role in biology as a chemical mediator of the effects of season on animal physiology and behavior. Seasonal changes in night length (scotoperiod) induce parallel changes in the duration of melatonin secretion (which occurs exclusively at night), so that it is longer in winter and shorter in summer. These changes in duration of nocturnal melatonin secretion, in turn, trigger seasonal changes in behavior. The retinohypothalamic-pineal (RHP) axis's responses to light are highly conserved in humans. Like other animals, humans secrete melatonin exclusively at night, and they interrupt its secretion when they are exposed to light during the nocturnal period of its secretion. In many individuals, the RHP axis also is capable of detecting changes in the length of the night and making proportional adjustments in the duration of nocturnal melatonin secretion, producing the type of melatonin message that animals use to trigger seasonal changes in their behavior. This has been shown both in naturalistic studies in which melatonin profiles were compared in summer and winter and in experimental studies in which melatonin profiles were compared after chronic exposure to long and short artificial "nights." Individuals who live in modern urban environments differ in the degree to which, or even whether, the intrinsic duration of melatonin secretion (the duration measured in constant dim light) responds to seasonal changes in the length of the solar night. Changes in the intrinsic duration of melatonin secretion that are induced by changes in the scotoperiod are highly correlated with changes in the intrinsic timing of the morning offset of secretion and are only weakly correlated with changes in the intrinsic timing of evening onset of secretion. This finding suggests that differences in the way in which individuals are exposed to, or process, morning light may explain differences in their responsiveness to changes in duration of natural and experimental scotoperiods. Although the human RHP axis clearly is capable of detecting changes in the length of the night and in producing the melatonin message that other animals use to trigger seasonal changes in their behavior, it is not yet known whether or how the human reproductive system or other systems respond to this message.

Animals↗

PubMed2005

The epidemiology of malaria in Bolifamba, a rural community on the eastern slopes of Mount Cameroon: seasonal variation in the parasitological indices of transmission.

The prevalences of malarial parasitaemia, fever, splenomegaly and anaemia and the levels of parasitaemia were investigated, through part of one wet season (in 2001) and the following dry season (in 2002), in 2157 subjects in the village of Bolifamba, in south-western Cameroon. Overall, 55.9% of the villagers checked in the wet season but only 49.5% of those examined in the dry season were found smear-positive for malaria (P<0.0001). Rainfall was found to be significantly associated with the mean level of parasitaemia (P=0.001). The prevalences of fever (40.3% v. 19.6%), splenomegaly (37.4% v. 4.0%) and marked splenomegaly (i.e. a Hackett's score of 2 or higher; 25.8% v. 2.4%) were all significantly higher in the wet season than in the dry (P<0.0001 for each). No seasonal difference was observed, however, in the prevalence of anaemia. Parasitaemia, fever, splenomegaly and anaemia were all significantly more common in the young children investigated (i.e. those aged < 5 years) than in the older subjects. When the data were subjected to a multiple logistic regression, age-group, anaemia, fever, and month of examination were all found to be significantly associated with the presence of malarial parasitaemia. The results of this large-scale study, the first of its kind in the Buea district of Cameroon, indicate the intense transmission of malarial parasites in rural Bolifamba, with young children at greatest risk. The data collected provide a useful 'base line' for an ongoing study to assess the immune status of the residents of Bolifamba.

Adolescent↗

PubMed1998

Effects of orally inhaled budesonide in seasonal allergic rhinitis.

It has previously been demonstrated that topical nasal treatment with glucocorticosteroids has significant effects on the bronchial airways. Less is known about effects on nasal disease by topical bronchial treatment with these drugs. The present study examined effects on nasal allergic disease of inhaled budesonide (avoiding nasal deposition of the drug). Patients with seasonal allergic rhinitis, but without asthma, were thus given inhalations of budesonide (600 microg b.i.d.) or placebo. The aim of the design was to allow the study of eosinophilic airway disease in a part of the airway other than the directly treated locus. Moderate to high birch pollen levels were recorded during the study season, and nasal symptoms were significantly increased in both treatment groups, although they were milder in patients receiving budesonide than in the placebo group (p<0.05). Nasal brush eosinophils and nasal lavage fluid levels of eosinophil cationic protein as well as blood eosinophils were increased during the season (p<0.05), but these increases were prevented by the inhaled budesonide. Nasal lavage fluid levels of alpha2-macroglobulin were particularly elevated in the placebo group but did not differ between patients receiving placebo and budesonide. Budesonide prevented the seasonal development of increased bronchoconstrictor responses to methacholine challenge (p<0.05). In conclusion, budesonide reduced the seasonal eosinophilia both in the circulation and in the nose along with an attenuation of seasonal nasal symptoms. Hence, at a daily dose of 600 microg b.i.d., known to cause no, or minimal, adverse effects, inhaled budesonide produces clinically significant anti-inflammatory effects in the entire airways, including the nasal mucosa, which is not exposed topically to the drug. We suggest that nasal and systemic anti-eosinophil actions are produced at commonly employed dose levels of orally inhaled budesonide.

Administration, Inhalation↗

PubMed2005

Open-label evaluation of azelastine nasal spray in patients with seasonal allergic rhinitis and nonallergic vasomotor rhinitis.

OBJECTIVE: The objective of the study was to evaluate the effectiveness of azelastine (Astelin) nasal spray, a topical second-generation antihistamine, in the treatment of symptoms of seasonal allergic rhinitis, seasonal allergic rhinitis with nonallergic triggers (mixed rhinitis), and nonallergic vasomotor rhinitis. RESEARCH DESIGN AND METHODS: A total of 2343 primary care physicians, allergists, ENT specialists, and other health professionals participated in this 2-week, open-label evaluation of azelastine nasal spray. Data were collected through a physician questionnaire that included patient demographics, rhinitis diagnosis, medication history, and inclusion/exclusion criteria; and two patient questionnaires that included symptom history, response to previous rhinitis medications, symptom control, and level of satisfaction with azelastine nasal spray. A completed physician questionnaire and two completed patient questionnaires were required for each patient to be included in the analysis. Patients who qualified for enrollment were given open-label azelastine nasal spray and instructed to administer 2 sprays per nostril twice daily for 2 weeks. RESULTS: A total of 1225 health professionals enrolled 7864 patients into the study. Completed physician and patient questionnaires were returned by 1081 health professionals and 5073 patients, 4364 of whom used azelastine nasal spray as their only rhinitis medication during the 2-week study period. The patients were predominantly caucasian (82.6%) and female (61.1%), with a mean age of 50 years. The majority had a diagnosis of mixed rhinitis (51.5%), followed by seasonal allergic rhinitis (32.3%), and nonallergic (vasomotor) rhinitis (16.2%). After 2 weeks of treatment, the percentage of patients reporting some control or complete control of individual symptoms ranged from 78% for postnasal drip in patients with nonallergic vasomotor rhinitis to 90% for sneezing in patients with seasonal allergic rhinitis. More than 85% of patients who reported difficulty sleeping or impairment of daytime activities due to rhinitis symptoms had improvement in these parameters. Azelastine nasal spray was well tolerated, the discontinuation rate due to adverse events was 2.3%. CONCLUSIONS: Azelastine nasal spray was reported to control all rhinitis symptoms, including nasal congestion, regardless of rhinitis diagnosis during the 2-week study period. Patients with seasonal allergic rhinitis and patients with seasonal allergic rhinitis plus nonallergic triggers were identified as patient types most likely to respond to azelastine nasal spray.

Administration, Intranasal↗

PubMed2005

Opportunities for detection and use of QTL influencing seasonal reproduction in sheep: a review.

Genetic improvement in traits associated with seasonal breeding in sheep is challenging because these traits have low heritabilities, are generally not expressed until late in life, are commonly recorded only in females, and are expressed only in some lambing seasons and management systems. Detection of quantitative trait loci and their use in marker-assisted selection could therefore substantially enhance selection responses. A population of sheep with an extended breeding season was developed through selection for fertility in spring matings and provides opportunities for further study of candidate genes influencing seasonal breeding. In particular, the melatonin receptor 1a gene is polymorphic in many sheep breeds and appears to influence a number of seasonal reproductive responses. In addition, a variety of clock genes have been identified in laboratory mammals and shown to influence biological rhythms. Mutations in these clock genes have been identified and shown to influence circadian periodicities and reproductive patterns in golden hamster and mouse. In sheep, expression of clock genes in the suprachaismatic nucleus and pars tuberalis (PT) suggests that "calendar" cells in the ovine PT play a role in maintaining circannual rhythms. Thus the various clock genes represent potentially important candidate genes that may be involved in control of seasonal breeding.

Animals↗

PubMed2003

Seasonal changes, sleep length and circadian preference among twins with bipolar disorder.

BACKGROUND: We aimed at studying the seasonal changes in mood and behaviour, the distribution of hospital admissions by season, and the persistence of the circadian type in twins with bipolar disorder and their healthy co-twins. METHODS: All Finnish like-sex twins born from 1940 to 1969 were screened for a diagnosis of bipolar type I disorder. The diagnosis was assessed with a structured research interview, and the study subjects (n = 67) filled in the Seasonal Pattern Assessment Questionnaire (SPAQ) and the Morningness-Eveningness Questionnaire (MEQ). For studying the persistence of the habitual sleep length and circadian type, we used data derived from the Finnish Twin Cohort Questionnaire (FTCQ). Bipolar twins were compared with their healthy co-twins. RESULTS: Bipolar twins had greater seasonal changes in sleep length (p = 0.01) and mood (p = 0.01), and higher global seasonality scores (p = 0.03) as compared with their co-twins with no mental disorder. Sunny days (p = 0.03) had a greater positive effect on wellbeing in the bipolar than healthy co-twins. CONCLUSIONS: Our results support the view that bipolar disorder is sensitive to the environmental influence in general and to the seasonal effect in specific. Exposure to natural light appears to have a substantial effect on wellbeing in twins with bipolar disorder.

Adult↗

PubMed2000

Seasonal variation in suicides: diminished or vanished. Experience from England and Wales, 1982-1996.

BACKGROUND: Seasonal variation in suicidal death has been observed in many countries. In particular, a cyclic variation was found for both men and women in England and Wales in the 1960s and 1970s. Men showed a single 12-month cycle whereas women showed two cycles. AIMS: To re-examine the seasonal variation in suicides in England and Wales for the period 1982-1996. METHOD: A harmonic analysis was used to detect the seasonality of the suicide data. RESULTS: The seasonal effect on suicide is greatly diminished in England and Wales. This is shown by the reduced amplitude and smaller proportion of variance accounted for by the season. CONCLUSIONS: The seasonal effect on suicide has either diminished or vanished.

Adolescent↗

PubMed1984

Endocrine control of the seasonal occurrence of ovulation in rhesus monkeys housed outdoors.

In female rhesus monkeys (n = 12) housed in a seminatural environment, serum gonadotropin and steroid levels fluctuated annually in a pattern indicative of a seasonally restricted period of ovulatory cycles in the fall and winter and anovulatory cycles in the spring and summer. This seasonal endocrine rhythm occurred independent of pregnancy and lactation, although the presence of a suckling infant delayed the onset of ovulation in the fall by 81 +/- 3.7 days (Dec. 4 vs. Sept 14). Except for serum PRL, levels of gonadotropin and ovarian hormones were similar in lactating and nonlactating females during the spring and summer anovulatory months. Serum levels of LH (less than 10 ng/ml), FSH (less than 4 micrograms/ml), and 17 beta-estradiol (E2; less than 30 pg/ml) were low throughout the summer anovulatory period, exhibiting a significant rise approximately 20 days before first ovulation. Serum progesterone levels were low throughout the 100 days before ovulation (less than 0.5 ng/ml) and did not rise until ovulation occurred. PRL levels remained elevated (greater than 20 ng/ml) in lactating females until 50 days before the first ovulation of the breeding season, but were low throughout the ovulatory, anovulatory, and ensuing ovulatory periods (less than 10 ng/ml). During the breeding period, females exhibited from two to six ovulations. Although the first ovulation of the breeding season occurred within a 40-day period for all females, a subset (n = 6) ceased ovulations significantly earlier than the remaining six females (Jan. 26 vs. March 3). The early cessation of ovulation for these females was associated with significantly lower body weight. After the last ovulation, FSH and E2 fell and remained low, at levels indistinguishable from those of the ensuing spring-summer anovulatory period. In contrast, in females who ceased ovulations later in the breeding season, the period following the luteal phase of the last ovulation was characterized by E2 and gonadotropin levels that were intermediate between those of the anovulatory months and normal follicular phase values. Serum progesterone levels were slightly but significantly elevated following the last ovulation for both groups of females. These data indicate that low basal levels of gonadotropin secretion during the seasonal anovulatory period may result from diminished GnRH secretion or from an alteration in pituitary sensitivity to GnRH stimulation. These data further suggest that the timing of ovulations and associated changes in the neuroendocrine system controlling gonadotropin secretion may be mediated by an environmental variable.

Animals↗

PubMed1987

Beta-endorphin secretion in rams related to season and photoperiod.

A newly established RIA was used to measure changes in the concentration of beta-endorphin in peripheral blood and pituitary tissue from adult Soay rams living outside under natural conditions and housed indoors under artificial photoperiods. A pronounced seasonal cycle in plasma beta-endorphin immunoreactivity occurred in the outdoor animals, with low levels in spring and early summer (February-May; less than 200 pg/ml plasma) and maximal levels 10-20 times higher in late summer and autumn (July-October). Seasonal changes in plasma levels of PRL, FSH, and cortisol, testis size, and body weight were also monitored; the seasonal cycle in the levels of immunoreactive beta-endorphin occurred in parallel with the cycle in plasma FSH and body weight. There were no significant seasonal changes in plasma cortisol concentrations. Marked changes in the plasma levels of beta-endorphin were also seen in rams kept under the artificial photoperiod regimen of alternating 12- to 16-week periods of long days (16 h of light and 8 h of darkness; 16L:8D) and short days (8L:16D). Transfer from long days to short days led to a greater than 20-fold increase in the levels of beta-endorphin, reaching a maximum after 4-8 weeks; the reverse switch in photoperiod led to a rapid decrease in the levels. There was no diurnal rhythm in the plasma levels of beta-endorphin based on hourly samples collected for 24 h under long and short days. The total content of immunoreactive beta-endorphin in the pituitary gland was lower in rams under short days than under long days, converse to the pattern in the blood. Sephadex chromatography of the plasma samples revealed that most of the beta-endorphin immunoreactivity coeluted with synthetic beta-endorphin-(1-31), and a small amount of activity eluted with beta-lipotropin. The seasonal and photoperiod-induced changes were largely due to changes in the levels of beta-endorphin. Extracts of pituitary tissue revealed a large proportion of beta-lipotropin to beta-endorphin compared to plasma, with no consistent change in ratio related to the photoperiod. The overall results illustrate that there are pronounced seasonal and photoperiod-induced changes in immunoreactive plasma beta-endorphin levels in the ram. Under artificial photoperiods, long days inhibit and short days stimulate beta-endorphin secretion. Under natural conditions, the development of refractoriness to both the inhibitory effects of long days and the stimulatory effects of short days may explain the timing of the annual cycle of beta-endorphin secretion.

Animals↗

PubMed1999

Thyroid hormones act primarily within the brain to promote the seasonal inhibition of luteinizing hormone secretion in the ewe.

In the ewe, thyroid hormones are required for the seasonal suppression of GnRH and LH secretion, thereby maintaining an annual rhythm in reproductive activity. The primary site of action of thyroid hormones is unknown; in particular, there is no evidence to distinguish a central from a peripheral action. In this study, we test the hypothesis that thyroid hormones can act directly within the brain to promote GnRH/LH seasonal inhibition. Ovariectomized estradiol-treated ewes were thyroidectomized late in the breeding season to prevent seasonal LH inhibition. T4 was then infused for 3 months, either peripherally or centrally. Neuroendocrine reproductive state was monitored by assaying the LH concentration in biweekly blood samples. Central infusion of low dose T4, which restored a physiological concentration of the hormone in cerebrospinal fluid of these thyroidectomized ewes, promoted the neuroendocrine changes that lead to anestrus. The serum LH concentration in these animals fell at the same time as the seasonal LH decline in euthyroid controls. Neither this same T4 dose infused peripherally nor vehicle infused centrally was effective; LH remained elevated, signifying blockade of the mechanism for anestrus. Our results provide strong evidence that thyroid hormones can act directly within the brain to promote seasonal inhibition of neuroendocrine reproductive function in the ewe.

Analysis of Variance↗

PubMed2003

Variation in levels of serum inhibin B, testosterone, estradiol, luteinizing hormone, follicle-stimulating hormone, and sex hormone-binding globulin in monthly samples from healthy men during a 17-month period: possible effects of seasons.

To obtain information on the scale of the intraindividual variation in testicular hormone, blood samples for inhibin B determination were collected monthly in 27 healthy male volunteers during a 17-month period. In addition, the traditional reproductive hormones FSH, LH, testosterone, estradiol, and SHBG were measured. The intraindividual variation in inhibin B over the study period was, on the average, 10%, corresponding to the assay variation of the inhibin B assay, indicating that most of the observed day to day variation in inhibin B levels in men could be explained by assay variation. A seasonal variation was observed in LH and testosterone levels, but not in the levels of the other hormones. The seasonal variation in testosterone levels could be explained by the variation in LH levels. The seasonal variation in LH levels seemed to be related to the mean air temperature during the month before blood sampling, but not to the length of daylight or the hours of sunshine. In conclusion, our data showed that day to day levels of inhibin B are relatively constant in men and do not seem to be influenced by seasonal factors. In contrast, we found a seasonal variation in LH and testosterone levels in men. The peak levels of both LH and testosterone were observed during June-July, with minimum levels present during winter-early spring. Air temperature, rather than light exposure, seems to be a possible climatic variable explaining the seasonal variation in LH levels.

Adult↗

PubMed2003

Seasonal variation of testosterone and waist to hip ratio in men: the Tromsø study.

Studies of seasonal variation in male testosterone levels show contradictory results. We report here a cross-sectional study of the seasonal variation in total and free testosterone, LH, and SHBG levels in 1548 men living in north Norway, a population exposed to a wide seasonal variation in temperature and daylight. Total testosterone showed a bimodal seasonal variation (P < 0.001) with a small peak in February, the nadir in June, and a more prominent peak in October and November. Free testosterone also showed a significant seasonal pattern (P < 0.001), with the peak in December and the nadir in August. These patterns persisted after adjusting for age and waist to hip ratio (P < 0.001). Lowest testosterone levels occurred in months with the highest temperatures and longest hours of daylight. Waist to hip ratio paralleled the change in daylight and temperature, with the highest values during the summer and was thus inversely related to the seasonal testosterone variation. The variations in hormone levels were large, with a 31% difference between the lowest and highest monthly mean level of free testosterone. Prospective studies are needed to establish the direction of the association and its etiology.

Adult↗

PubMed1985

Physical exercise-induced changes and season-associated differences in the pituitary-ovarian function of runners and joggers.

The hormonal responses to energetic chronic exercise and to seasonal shift from autumn to spring were evaluated by measuring concentrations of serum FSH, LH, PRL, estradiol (E2), progesterone (P), testosterone (T), and sex hormone-binding globuline (SHBG) during 1 menstrual cycle in the autumn (light training season) and 1 in the spring (hard training season) in 18 endurance runners and 12 age-matched nonrunning women, and in 13 joggers and 11 age-matched nonjogging women. The appearance, growth, and maximal size of the ovarian follicles were monitored by ultrasonography. The high intensity training of the runners was associated with decreased concentrations of FSH on cycle days 7-8 in the autumn, E2 on cycle days 12-13 in the spring and days 22-23 in both seasons, P on cycle days 20-21 in both seasons and days 22-23 in the autumn, and T on cycle days 12-13, 14-15, and 22-23 in the spring. Jogging, however, did not alter the concentrations of these hormones. Using as criteria the presence of 2 or 3 abnormal values of the 3 indicators used for evaluation of folliculogenesis (midfollicular E2 lower than 0.09 nmol/liter, luteal phase P lower than 7 nmol/liter, and peak diameter of the largest ovarian follicle less than 15 mm), seriously disturbed folliculogenesis was found in 50% of the 32 study cycles of the runners and 9% of the 23 cycles of their controls (P less than 0.01). In all four study groups, there was a significant seasonal difference in the concentrations of ovarian hormones, with lowered E2, P, and T levels in the autumn. There were no differences in the serum concentrations of SHBG between the study groups or between the autumn and the spring. High training activity and a dark photoperiod appeared to independently suppress ovarian activity and were not associated with chronic changes in anterior pituitary hormone or SHBG concentrations.

Adolescent↗

PubMed1991

Abnormal pituitary-adrenal responses to corticotropin-releasing hormone in patients with seasonal affective disorder: clinical and pathophysiological implications.

CRH has been shown to produce increased locomotion, arousal, and anorexia in experimental animals. A deficiency of CRH in patients with seasonal affective disorder could contribute to the characteristic lethargy, hypersomnia, and hyperphagia characteristic of this illness. To test this hypothesis, we studied basal plasma ACTH and cortisol levels and their responses to ovine CRH in controls and depressed patients with seasonal affective disorder before and after light treatment. Untreated seasonal affective disorder patients showed normal basal plasma cortisol and ACTH levels, but their responses to CRH tended to be delayed and were significantly reduced. When patients were studied after 9 days of light treatment, a significant increase in plasma ACTH and cortisol responses to CRH was observed. Our findings in untreated patients with seasonal affective disorder are similar to those in patients with Cushing's disease 2 weeks after transsphenoidal hypophysectomy, who uniformly show sustained suppression of their CRH neuron because of long-standing hypercortisolism. This findings suggest that the CRH neuron of patients with seasonal affective disorder is hypofunctional. We postulate that the clinical symptomatology in patients with seasonal affective disorder could reflect deficient activity of this important arousal-producing system.

Adrenocorticotropic Hormone↗