Testosterone dose-dependency of sexual and nonsexual behaviors in the gonadotropin-releasing hormone antagonist-treated male rat.

The testosterone dose-dependency of several mating and nonmating behaviors was examined in the male rat, chemically castrated with a GnRH antagonist analog. Graded doses of testosterone enanthate (TE) were given to male rats to reinstate behaviors abolished by GnRH antagonist treatment. GnRH antagonist treatment alone markedly lowered serum LH, FSH and T concentrations and ventral prostate and testis weights. Open field behaviors were not significantly affected by GnRH antagonist treatment or castration. Scent-marking behavior was markedly suppressed by both castration and GnRH antagonist and restored by the lowest dose of TE (0.05 mg). All measures of male sexual behavior were impaired by GnRH antagonist treatment and castration and restored by the lowest dose of TE (0.05 mg). The doses of TE required to restore normal ventral prostate weights and testis weights were higher than those required to maintain scent marking and mating behaviors. No direct behavioral effects of the GnRH antagonist, other than those that can be explained by GnRH antagonist-induced suppression of testosterone were observed. The finding that sexual and nonsexual behaviors in the male rat have different testosterone requirements from those maintaining spermatogenesis and fertility may have significant implications for contraception.

Pharmacokinetics and pharmacodynamics of a parenteral testosterone microsphere formulation in the male rat. Demonstration of dose dependence and controlled release.

This study examined the pharmacokinetics (the time course and pattern of testosterone release) and pharmacodynamics (effects on accessory sex organ weights, and serum LH and FSH levels) of a biodegradable testosterone microsphere formulation in the male rat. Two hundred seventy-five 55-day-old, sexually mature male rats underwent surgical orchiectomy or sham surgery and were divided into five groups as follows, to receive placebo or testosterone microsphere systems designed to release 25, 75, or 225 micrograms/day testosterone: group I: intact age-matched controls, sham operated, placebo microspheres; group II: surgically orchiectomized, placebo microspheres; group III: surgically orchiectomized, 25 micrograms/day testosterone microspheres; group IV: surgically orchiectomized, 75 micrograms/day testosterone microspheres; and group V: surgically orchiectomized, 225 micrograms/day testosterone microspheres. Serum testosterone levels were fairly uniform from day 2 to 85 without any significant trend. After day 100, serum testosterone levels gradually fell into the castrate range by day 196. There was a dose-dependent increase in serum testosterone levels in groups III, IV, and V over those seen in group II (castrated rats, placebo treated). Prostate and seminal vesicle weights were significantly lower in castrated animals treated with placebo or the 25-micrograms/day testosterone microsphere system (group III). Mean prostate and seminal vesicle weights in groups IV and V were not significantly different from those in intact controls (group I) in the first 85 days. After day 85-100, seminal vesicle and prostate weights declined gradually in groups III, IV, and V, approaching castrate range by day 196.(ABSTRACT TRUNCATED AT 250 WORDS)

Ecology and ovarian function among Lese women of the Ituri Forest, Zaire.

Ovarian function is examined in 35 Lese women inhabiting the Ituri Forest of northeastern Zaire over a period of 4 months through measurements of progesterone in saliva samples collected twice weekly. Ovulatory frequency is found to be only 56% on average, with a pattern of age variation similar to that observed in western women, though lower in level at each age. Average luteal progesterone levels of the Lese women are lower than those of Boston controls even if only ovulatory cycles are considered. Women with the poorest nutritional status, inferred from longitudinal weight changes and weight for height, show the greatest compromise of ovarian function, and the average ovulatory frequency of the whole sample declines in parallel with a period of weight loss over four months. It is suggested that low ovulatory frequency and luteal insufficiency contribute to the low fecundity of the Lese population and that nutritional status is likely to be one of the ecological factors modulating this effect.

Salivary progesterone and luteal function in two low-fertility populations of Northeast Zaire.

PIP: 30 Ituri women (Zaire) -- 14 Efe and 16 Balese -- were targeted as subjects in this study designed to verify that, under field conditions, the salivary steroid method can reliably discern follicular and luteal levels of progesterone in normal menstrual cycles and to examine the hypothesis that infertility among these women is due to tubal factors. Findings of normal ovulatory function in fertile women would support the hypothesis; findings of abnormal gonadal function might either indicate a chronic endocrine imbalance or the short-term effects of nutritional and other stressors. All potential subjects ranged in age between 20-35 years, were involved in stable conjugal unions, had no nursing children, and reported either no births or none within the last 6 years. 25 women completed the study. The Boston field control subjects consisted of 18 volunteers ranging in age between 18-43 years. All reported a history of regular menstrual cycles and were nither using oral steroid contraceptives nor engaged in a regular exercise program. The African women had significantly lower luteal progesterone levels than did the Boston controls. Additionally, a significantly higher proportion of the African women failed to demonstrate clear luteal activity, suggesting that a higher rate of anovulation contributed to the low average luteal progesterone levels. The composite-cross-sectional profile for the Ituri Forest women suggests that the average luteal phase for this group was shorter than for the Boston controls. Further investigations need to determine whether gonadal dysfunction such as observed in this study is a regular feature of the reproductive physiology of women in the Ituri Forest, or whether it emerges only in periods of food shortage and significant weight loss. Gonorrhea may be the major cause of infertility in the Ituri region, but it is likely that other factors directly affecting gonadal function contributed to the observed pattern of low fertility. Clearly, the study illustrates the potential usefulness of salivary steroid assays.^ieng

Nutritional status of Efe pygmies and Lese horticulturists.

We assessed the nutritional status of 90 pygmies (Efe) and 211 members of a neighboring horticultural Lese in the Ituri forest in northeast Zaire. Clinical signs of iron and iodine deficiency were highly prevalent, but the frequency of these and other clinical signs of nutritional deficiency did not differ between the two groups. Infectious diseases such as yaws, cellulitis, and filiariasis were common. Absolute heights and weights of both Efe males and females aged 2-18 years were less than the 5th percentile of the National Center for Health Statistics standards. Weights for height of both groups were within the normal range. Weights and heights, expressed as percentages of the 50th percentile for age and sex, were significantly lower (P less than .001) in Efe males and females than among Lese males and females, but weights for height did not differ significantly. Z-Scores of height and weight were also significantly lower in Efe males and females than among their Lese counterparts. The differences in weight and height, expressed either as a percentage of the 50th percentile or as Z-scores, were most apparent in older adolescents and persisted among adults. The normal weight for height among both populations indicated that acute undernutrition did not exist at the time of the survey. Despite comparable levels of adult fatness, measured by triceps skinfold thickness, heights of Efe males and females were lower than those of the Lese. These observations support the hypothesis that genetic differences account for the short stature of the Ituri pygmy. However, because the environments shared by the two groups are not identical and because other practices differ, nutritional effects cannot be excluded.

Pregnancy discovery and acceptance among low-income primiparous women: a multicultural exploration.

OBJECTIVES: As part of a larger study exploring psychosocial factors that influence self-care and use of health care services during pregnancy, we investigated the process of pregnancy discovery and acceptance among a culturally diverse group of women who had given birth to their first child in the year preceding data collection. METHODS: Eighty-seven low-income women from four cultural groups (African American, Mexican, Puerto Rican, and white) participated in eight focus groups held in their communities. The focus groups were ethnically homogenous and stratified by early and late entry into prenatal care. A social influence model guided the development of focus group questions, and the study followed a participatory action research model, with community members involved in all phases of the research. RESULTS: Issues that emerged from the focus groups as possible influences on timing of pregnancy recognition include the role of pregnancy signs and symptoms and pregnancy risk perception in the discovery process, the role of social network members in labeling and affirming the pregnancy, concerns about disclosure, "planning" status of the pregnancy, and perceived availability of choices for resolving an unintended pregnancy. CONCLUSIONS: The pregnancy discovery process is complex, and when protracted, can potentially result in delayed initiation of both prenatal care and healthful pregnancy behaviors. Enhancing our understanding of pregnancy discovery and acceptance has clear implications for primary and secondary prevention. Future research is needed to further explain the trajectory of pregnancy discovery and acceptance and its influence on health behaviors and pregnancy outcome.

The ecology of birth seasonality among agriculturalists in central Africa.

The Lese are subsistence farmers living in the Ituri Forest of north-east Zaïre. They exhibit significant birth seasonality, with lowest frequencies of conception when food production is least, nutritional status is low and ovarian function, as measured by salivary steroid hormone levels, is reduced. Efe pygmy foragers, who live in the same geographical area but are less dependent on cultivated foods and have a more flexible life style, do not exhibit frequent fluctuations in nutritional status nor significant birth seasonality. These findings support a model of birth seasonality relating climatic variables to variation in fertility through a causal chain linking rainfall to food production to energy balance to ovarian function to fertility. The model, which emphasises an ecological approach to the study of human reproduction, should have broad applicability since seasonality of food production and energy balance is widespread geographically and across a wide variety of economies and cultures.

PIP: Researchers compared 1980-87 data on rainfall, garden size, nutritional status, ovarian function, and births among the Lese subsistence farmers and the nomadic Efe pygmies who lived in the Ituri Forest in northeast Zaire to analyze the ecology of human birth seasonality. Natural fertility for the Lese was 2.35 and 2.56 for the Efe. Rainfall patterns determined the size of Lese gardens (p.05) which in turn determined nutritional status for both the Lese and the Efe (p.01), but particularly the Lese. Negative changes in female nutritional status diminished ovarian function. Specifically, women with lower indices of weight for height and who had lost 2 kg during the study had lower peak progesterone levels and ovulatory frequency than women who lost =or 2 kg. Menstrual cycles lengthened and duration of menstrual flow decreased with a decline in nutritional status. Conceptions were significantly reduced in May-July for the Lese (p=.012). For both Efe and Lese women, conceptions were lowest in May and highest in September. Lese women experienced considerably fewer conceptions during the periods with poor food availability than during other months (p=.002). The corresponding p value was almost significant for Efe women (.55). Thus Efe women experience less fluctuations in nutritional status than did Lese women, but variability in the seasonal pattern of rainfall did determine variation in fertility. The causal chain was rainfall - determined food production which determined energy balance which determined ovarian function which determined fertility. This model can be applied to any population in any geographic region. It integrates knowledge of behavior and cultural practices with the biology of human reproduction.