Nancy M Czekala
Biographic Data
| ID | 5209655 |
|---|---|
| NAME | Nancy M Czekala |
| GIVEN NAMES | Nancy M |
| FAMILY NAME | Czekala |
| SIGNATURE | CZEKALA N M |
| AFFILIATIONS | Zoological Society of San Diego |
| VERIFIED | No |
| TOTAL WORKS | 16 |
| TOTAL CITATIONS | 12 |
| AUTHOR COUNT | 16 |
| EDITOR COUNT | 0 |
| FIRST PUBLICATION YEAR | 1982 |
| LATEST PUBLICATION YEAR | 2012 |
| H-INDEX | 1 |
Juggling Priorities: Female Mating Tactics in P hayre's Leaf Monkeys
Extended sexual receptivity in primates is thought to facilitate paternity confusion, thus decreasing the risk of infanticide. However, females might also provide some indication of ovulation to attract preferred males during fertile periods. We examined female mate preferences across defined receptive periods ( N = 59) in a group of wild P hayre's leaf monkeys ( T rachypithecus phayrei crepusculus ) at P hu K hieo W ildlife S anctuary (February–…
Reproductive characteristics of wild female Phayre's leaf monkeys
Understanding female reproductive characteristics is important for assessing fertility, interpreting female behavior, and designing appropriate conservation and captive management plans. In primate species lacking morphological signs of receptivity, such as most colobines, determination of reproductive parameters depends on the analysis of reproductive hormones. Here, we use fecal hormone analysis to characterize cycle patterns ( N =6 females) an…
Urinary androgen and corticoid levels in captive, male Western lowland gorillas ( Gorilla g. gorilla ): Age‐ and social group‐related differences
Urinary androgen and corticoid levels were measured for 52 captive male Western lowland gorillas to examine age‐related variance and potential differences resulting from various social situations. Significant diurnal variation was present in both hormones. Age‐related differences in androgens revealed that males experienced two stages of androgen increase and one stage of decrease: increases occurred from juvenile (less than 10 yr of age) to suba…
Male orangutan subadulthood: A new twist on the relationship between chronic stress and developmental arrest
Both in the wild and in captivity, a marked and enduring arrest of secondary sexual developmental occurs in some male orangutans ( Pongo pygmaeus ) (Kingsley [ 1982 ] The Orang‐Utan: Its Biology and Conservation, The Hague: Junk; Utami [ 2000 ]). Researchers have hypothesized that chronic stress, perhaps related to aggression from mature males, causes endocrine changes altering growth and maturation rates in these males (Maple [1980] Orangutan Be…
Monitoring hormones in urine and feces of captive bonobos (Pan paniscus)
Growth hormone and thyroid stimulating hormone concentrations in captive male orangutans: Implications for understanding developmental arrest
There are two morphs of reproductive male in orangutans. Both morphs span the age range from adolescent to adult, but "subadult" males are smaller in size and lack secondary sexual features. In this study, urine samples were collected over a 2 year period from 23 captive male orangutans in order to define the endocrinology of this apparent arrest of secondary sexual development. Three males were juveniles, 3 to 5 years of age; seven males showed …
Reproductive monitoring of free-ranging female mountain gorillas by urinary hormone analysis
Frequent urine samples from three habituated free-ranging adult female mountain gorillas were collected during a four-week period in order to characterize, by analysis of urinary hormones, their ovarian cycle, and to diagnose pregnancy. A conceptive cycle and two cycles that did not result in full term pregnancy were monitored. Behavioral and physiological observations of mating and labial swellings were correlated to urinary hormone results. Mat…
Monitoring pregnancy in twinning pygmy loris (Nycticebus pygmaeus) using fecal estrogen metabolites
Estrone and estrone conjugates were measured in the feces of three female pygmy lorises (Nycticebus pygmaeus) throughout estrus, pregnancy, and the postpartum period. Two females gave birth to twins, while the third had a single stillborn. A comparison between the hormonal profiles of these three pregnancies with each other and with previously reported pregnancies resulting in singletons or twins [Jurke et al., American Journal of Primatology 41:…
Reproductive hormone profiles in captive male orangutans: Implications for understanding developmental arrest
For many years researchers have described some male orangutans as "subadult." These males are of adolescent to adult age and are reproductive, but have little to no secondary sexual trait development. Until now the only endocrine study of this arrest of secondary sexual trait development was performed by Kingsley (1982, 1988). She found that "subadult" or arrested males have lower testosterone levels than similar age developing adolescents or adu…
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 conse…
A preliminary investigation of urinary testosterone and cortisol levels in wild male mountain gorillas
Urinary steroid hormone levels were measured in wild male mountain gorillas (Gorilla gorilla beringei) to determine how levels of testosterone and cortisol corresponded with age and social rank. Urine samples were collected noninvasively from 18 males, ranging in age from 3-26 years, in three groups of wild mountain gorillas at the Karisoke Research Center, Rwanda, Africa, and samples were analyzed using radioimmunoassay procedures. Males were cl…
Assessment of luteal competency by urinary hormone evaluation in the captive female gorilla
Analysis of urinary estrone conjugates and pregnanediol‐3‐glucuronide were used to document ovarian events in female gorillas known to be fertile. These normal parameters were used to assess ovarian function in gorillas suspected as infertile. Insufficient luteal hormonal dynamics were observed in the infertile group. Based on this observation, exogenous progesterone as the only treatment was administered to infertile females post ovulation and m…
Excretion of radiolabeled estradiol metabolites in the slow loris ( Nycticebus coucang )
The excretion pattern of estradiol was studied in the slow loris Nycticebus coucang) and the ring‐tailed lemur (Lemur catta) in order to compare steroid excretion in two representative prosimian species. Daily urinary estrone conjugate measurements in the female loris provided little information when applied over prolonged periods. As a result of these negative data, a metabolic study was performed to determine if estrogen excretion patterns in t…
Direct measurements of urinary estrone conjugates during the normal menstrual cycle of the gorilla ( Gorilla gorilla )
A direct immunoassay for urinary estrone conjugates (estrone sulfate and estrone glucuronide) was used to assess the preovulatory estrogen rise in normal gorilla menstrual cycles. Immunoreactive estrone conjugates in samples concomitantly assessed for total estrogen immunoreactivity reflected similar profiles throughout the cycle; however, the speed and resolution of the direct assay for conjugates indicate this method to be more accurate in moni…
A practical approach to evaluation of fertility in the female gorilla
Measurements of urinary estrogen, pregnanediol-3-glucuronide, and bioactive luteinizing hormone indexed by creatinine on a daily basis in female gorillas reflect ovarian function. The use of small urine samples obviates the need for capture, restraint, or isolation and provides the basis for a nonstressful evaluation of reproductive status or fertility. Initial attempts at artificial insemination have thus far been unsuccessful when the fertile p…
Urinary immunoreactive estrogen and pregnanediol‐3‐glucuronide during the normal menstrual cycle of the female lowland gorilla ( Gorilla gorilla )
Urine samples were taken daily during 22 menstrual cycles of six normal adult female gorillas. Urine was analyzed for total immunoreactive estrogens (E t ) and pregnanediol‐3‐glucuronide (PdG) and indexed by creatinine (Cr). An average cycle length of 32 ± 1 days (mean ± SE) with a range of 25–42 days is reported. Estrogen values range from 4 to 128 ng/mg Cr and show a midcycle peak and a midluteal rise. PdG values range from 0.01 to 2.4 μg/mg Cr…
Male orangutan subadulthood: A new twist on the relationship between chronic stress and developmental arrest
Both in the wild and in captivity, a marked and enduring arrest of secondary sexual developmental occurs in some male orangutans ( Pongo pygmaeus ) (Kingsley [ 1982 ] The Orang‐Utan: Its Biology and Conservation, The Hague: Junk; Utami [ 2000 ]). Researchers have hypothesized that chronic stress, perhaps related to aggression from mature males, causes endocrine changes altering growth and maturation rates in these males (Maple [1980] Orangutan Be…
A practical approach to evaluation of fertility in the female gorilla
Measurements of urinary estrogen, pregnanediol-3-glucuronide, and bioactive luteinizing hormone indexed by creatinine on a daily basis in female gorillas reflect ovarian function. The use of small urine samples obviates the need for capture, restraint, or isolation and provides the basis for a nonstressful evaluation of reproductive status or fertility. Initial attempts at artificial insemination have thus far been unsuccessful when the fertile p…
Urinary immunoreactive estrogen and pregnanediol‐3‐glucuronide during the normal menstrual cycle of the female lowland gorilla ( Gorilla gorilla )
Urine samples were taken daily during 22 menstrual cycles of six normal adult female gorillas. Urine was analyzed for total immunoreactive estrogens (E t ) and pregnanediol‐3‐glucuronide (PdG) and indexed by creatinine (Cr). An average cycle length of 32 ± 1 days (mean ± SE) with a range of 25–42 days is reported. Estrogen values range from 4 to 128 ng/mg Cr and show a midcycle peak and a midluteal rise. PdG values range from 0.01 to 2.4 μg/mg Cr…
Direct measurements of urinary estrone conjugates during the normal menstrual cycle of the gorilla ( Gorilla gorilla )
A direct immunoassay for urinary estrone conjugates (estrone sulfate and estrone glucuronide) was used to assess the preovulatory estrogen rise in normal gorilla menstrual cycles. Immunoreactive estrone conjugates in samples concomitantly assessed for total estrogen immunoreactivity reflected similar profiles throughout the cycle; however, the speed and resolution of the direct assay for conjugates indicate this method to be more accurate in moni…
Excretion of radiolabeled estradiol metabolites in the slow loris ( Nycticebus coucang )
The excretion pattern of estradiol was studied in the slow loris Nycticebus coucang) and the ring‐tailed lemur (Lemur catta) in order to compare steroid excretion in two representative prosimian species. Daily urinary estrone conjugate measurements in the female loris provided little information when applied over prolonged periods. As a result of these negative data, a metabolic study was performed to determine if estrogen excretion patterns in t…
Assessment of luteal competency by urinary hormone evaluation in the captive female gorilla
Analysis of urinary estrone conjugates and pregnanediol‐3‐glucuronide were used to document ovarian events in female gorillas known to be fertile. These normal parameters were used to assess ovarian function in gorillas suspected as infertile. Insufficient luteal hormonal dynamics were observed in the infertile group. Based on this observation, exogenous progesterone as the only treatment was administered to infertile females post ovulation and m…
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 conse…
A preliminary investigation of urinary testosterone and cortisol levels in wild male mountain gorillas
Urinary steroid hormone levels were measured in wild male mountain gorillas (Gorilla gorilla beringei) to determine how levels of testosterone and cortisol corresponded with age and social rank. Urine samples were collected noninvasively from 18 males, ranging in age from 3-26 years, in three groups of wild mountain gorillas at the Karisoke Research Center, Rwanda, Africa, and samples were analyzed using radioimmunoassay procedures. Males were cl…
Monitoring pregnancy in twinning pygmy loris (Nycticebus pygmaeus) using fecal estrogen metabolites
Estrone and estrone conjugates were measured in the feces of three female pygmy lorises (Nycticebus pygmaeus) throughout estrus, pregnancy, and the postpartum period. Two females gave birth to twins, while the third had a single stillborn. A comparison between the hormonal profiles of these three pregnancies with each other and with previously reported pregnancies resulting in singletons or twins [Jurke et al., American Journal of Primatology 41:…
Reproductive hormone profiles in captive male orangutans: Implications for understanding developmental arrest
For many years researchers have described some male orangutans as "subadult." These males are of adolescent to adult age and are reproductive, but have little to no secondary sexual trait development. Until now the only endocrine study of this arrest of secondary sexual trait development was performed by Kingsley (1982, 1988). She found that "subadult" or arrested males have lower testosterone levels than similar age developing adolescents or adu…
Monitoring hormones in urine and feces of captive bonobos (Pan paniscus)
Growth hormone and thyroid stimulating hormone concentrations in captive male orangutans: Implications for understanding developmental arrest
There are two morphs of reproductive male in orangutans. Both morphs span the age range from adolescent to adult, but "subadult" males are smaller in size and lack secondary sexual features. In this study, urine samples were collected over a 2 year period from 23 captive male orangutans in order to define the endocrinology of this apparent arrest of secondary sexual development. Three males were juveniles, 3 to 5 years of age; seven males showed …
Reproductive monitoring of free-ranging female mountain gorillas by urinary hormone analysis
Frequent urine samples from three habituated free-ranging adult female mountain gorillas were collected during a four-week period in order to characterize, by analysis of urinary hormones, their ovarian cycle, and to diagnose pregnancy. A conceptive cycle and two cycles that did not result in full term pregnancy were monitored. Behavioral and physiological observations of mating and labial swellings were correlated to urinary hormone results. Mat…
Urinary androgen and corticoid levels in captive, male Western lowland gorillas ( Gorilla g. gorilla ): Age‐ and social group‐related differences
Urinary androgen and corticoid levels were measured for 52 captive male Western lowland gorillas to examine age‐related variance and potential differences resulting from various social situations. Significant diurnal variation was present in both hormones. Age‐related differences in androgens revealed that males experienced two stages of androgen increase and one stage of decrease: increases occurred from juvenile (less than 10 yr of age) to suba…
Male orangutan subadulthood: A new twist on the relationship between chronic stress and developmental arrest
Both in the wild and in captivity, a marked and enduring arrest of secondary sexual developmental occurs in some male orangutans ( Pongo pygmaeus ) (Kingsley [ 1982 ] The Orang‐Utan: Its Biology and Conservation, The Hague: Junk; Utami [ 2000 ]). Researchers have hypothesized that chronic stress, perhaps related to aggression from mature males, causes endocrine changes altering growth and maturation rates in these males (Maple [1980] Orangutan Be…
Reproductive characteristics of wild female Phayre's leaf monkeys
Understanding female reproductive characteristics is important for assessing fertility, interpreting female behavior, and designing appropriate conservation and captive management plans. In primate species lacking morphological signs of receptivity, such as most colobines, determination of reproductive parameters depends on the analysis of reproductive hormones. Here, we use fecal hormone analysis to characterize cycle patterns ( N =6 females) an…
Juggling Priorities: Female Mating Tactics in P hayre's Leaf Monkeys
Extended sexual receptivity in primates is thought to facilitate paternity confusion, thus decreasing the risk of infanticide. However, females might also provide some indication of ovulation to attract preferred males during fertile periods. We examined female mate preferences across defined receptive periods ( N = 59) in a group of wild P hayre's leaf monkeys ( T rachypithecus phayrei crepusculus ) at P hu K hieo W ildlife S anctuary (February–…
Biology (15 works) · Hormone (12 works) · Medicine (12 works) · Primate Behavior and Ecology (12 works) · Endocrinology (8 works) · Estrogen (8 works) · Endocrinology (7 works) · Gorilla (7 works) · Internal Medicine (7 works) · Animal Behavior and Reproduction (6 works)