Monitoring fecal samples for estrogen excretion across the ovarian cycle in Goeldi's monkey (Callimico goeldii)

Evolution of oestrogen functions in vertebrates

Steroidal oestrogens have been isolated from marine and terrestrial animals representative of all major classes of vertebrates including fish, amphibians, reptiles, birds and mammals. In general, oestrogens are responsible for most features characteristic of the female sex of a species, such as metabolic, behavioural and morphological changes during the stages of reproduction; they also support several processes in males. The evolution of the hormonal system always involves both the ligand and its sites of interaction. In the case of oestrogens, the steroid producing enzymes, mainly the aromatase complex, and the oestrogen receptor belong together within their co-evolution. The finding of oestrogenic steroids, the more recent identification of aromatase and receptor genes and their expression fit together, thereby confirming the importance for all vertebrates. Within the present paper, the evolution of the physiological functions of oestrogens from oviparous vertebrates to Eutherian mammals, oestrogen biosynthesis, metabolization and signalling pathways will be reviewed in detail.

Non-invasive detection and monitoring of estrus, pregnancy and the postpartum period in pygmy loris (Nycticebus pygmaeus) using fecal estrogen metabolites

Estrone-conjugates (E1C) were measured in the feces of six female pygmy lorises (Nycticebus pygmaeus) during estrus (n = 12), pregnancy (n = 4) and the postpartum period (n = 3). Noninvasive feces collection permitted frequent sampling throughout estrus and pregnancy, without disturbance of animals. The estrous period was defined as an increase in fecal E1C levels above an average of 70 ng/g feces with peaks above 100 ng/g feces obtained in consecutive fecal samples collected over a 6- to 11-day period between the end of July and the first third of October. Comparison of the periovulatory profile of E1C and the stage of labial opening of the vagina revealed a high agreement (P < 0.001). In all pregnant females, an E1C rise was found approximately 47 days postestrus, the source of which may be the growing fetal placental unit. Estimated gestation lengths ranged between 187 and 198 days (n = 4).

Steroid excretion during the ovarian cycle in captive and wild muriquis, Brachyteles arachnoides

Urine, feces, and copulation frequency were collected from two captive muriqui females, Brachyteles arachnoides, at the Centro de Primatologia do Rio de Janeiro following the resumption of postpartum ovarian cycles. Fecal steroid profiles from seven wild muriqui females at the Estação Biologica de Caratinga, Minas Gerais, Brazil, were compared to the captive females to determine the approximate patterns of steroid excretion relative to the urinary LH peak. Hormonal profiles from one of the captive female muriquis revealed a discrete urinary LH peak. For this female, fecal progesterone increased on the same day as the urinary LH peak, while fecal estradiol increased 6 days later and urinary steroids increased 5 days later. For both captive females, the onset of fecal progesterone increase was preceded by the onset of copulations, which occurred during at least a 5-day period. The complete fecal hormonal profiles of the one captive female for which continuos data were available were similar to those found in wild muriqui monkeys, with the onset of an increase in sustained progesterone levels occurring several days prior to the onset of sustained estradiol increase. These patterns suggest that fecal progesterone may be excreted rapidly in this species. The onset of sustained increase in fecal progesterone levels, together with the consistent delay in the onset of the sustained increase in estradiol, may provide the best indicators of the periovulatory period for muriqui females.

Recent advances in noninvasive techniques to monitor hormone-behavior interactions

This paper reviews recent advances in field endocrinology, a focus as well as a method in primatology and behavioral ecology that permits the examination of social behavior and life history through hormonal investigations in natural settings. Endocrine data complements the traditional behavioral data collected by field scientists by providing quantitative measures for the examination of adaptive tradeoffs, costs of social strategies, and reproductive and social significance of mating events. Further, investigations of the physiological mechanisms of reproductive constraint provide tests of the adaptive significance of reproductive skew in cooperative and competitive breeders. Hormone data also can provide insights into the costs of competition and aggression and the role of temperament in individual reproductive success and the evolution of social systems. New, noninvasive methods for the collection of this information have augmented and expanded field endocrinology through the use of techniques that do not require potentially confounding physical or physiological manipulations. Specifically, urine and fecal samples can be collected from free-ranging animals and contain gonadal and adrenal hormones that parallel profiles of serum hormones. Sampling, preservation, extraction, and assay methods for the analysis of excreted steroids are reviewed along with the species and questions to which these methods have been applied.