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PubMed1991

Effects of testosterone propionate, prolactin and photoperiod on feeding behaviours of Indian male weaver birds.

Testosterone propionate (TP) is not associated with the total food consumption of the male weaver bird. Reproductively active birds maintained under long daylength eat continuously however under short daylength they eat in 2-3 peaks and are also reproductively quiescent. Results show that total food consumption is independent of length of photoperiod/reproductive states of the bird, perhaps associated with the caloric demand of the bird. Prolactin (PRL) stimulates the testicular development of the bird. PRL induced weight loss does not involve decrease food intake as there is no change in the total food consumption of the bird and therefore, reflects the improper utilization of the food. This hormone alters the feeding behaviour from cyclic (2-3 peaks) to continuous pattern.

Animals↗
PubMed1997

Change in photoperiodic cycle affects life span in a prosimian primate (Microcebus murinus).

The lesser mouse lemur, a small prosimian primate, exhibits seasonal rhythms strictly controlled by photoperiodic variations. Exposure to day lengths shorter than 12 h results in complete sexual rest, fattening, lethargy, and reduced behavioral activities; whereas exposure to day lengths greater than 12 h induces sexual activity, an increase in behavioral activities, and high hormonal levels. The objective of this study was to test whether long-term acceleration of seasonal rhythms may affect survival and longevity of this primate. In captivity, acceleration of seasonal rhythms was obtained by exposing the animals to an accelerated photoperiodic regimen consisting of 5 months of long photoperiod followed by 3 months of short photoperiod. The age-specific survival rate in animals exposed from birth to accelerated photoperiodic conditions (n = 89) was compared to the age-specific survival rate of animals maintained under a natural photoperiod (n = 68). Independent of sexes, the mean life span (45.5 +/- 2.1 months) and maximal survival (79.3 +/- 3.3 months) were significantly (p < .01) shortened in mouse lemurs exposed to the accelerated photoperiodic cycle compared to those in animals living under annual photoperiod (63.2 +/- 2.5 and 98 +/- 3.9 months for mean life span and maximal survival, respectively). This reduction of about 30% of life span was not accompanied by a desynchronization of biological rhythms under photoperiodic control and was not related to an increase in reproduction or in duration of time spent in active conditions. However, when the number of seasonal cycles experienced by 1 individual is considered rather than chronological age, the mean life span was 5 seasonal cycles and maximum survival reached 9-10 cycles, independent of sex or of photoperiodic regimen. These results suggest that in mouse lemurs, as in other seasonal mammals, longevity may depend on the expression of a fixed number of seasonal cycles rather than on a fixed biological age.

Aging↗
PubMed1984

General reproduction, perinatal-postnatal, and teratology studies of nitrofurantoin macrocrystals in rats and rabbits.

Urinary tract infections in pregnant women are common and require prompt, effective treatment. Currently, no antibacterial agents have received regulatory approbation for use without restriction during pregnancy. The choice of a drug for use in pregnant women requires careful examination of its possible maternal and fetal toxicity as well as its teratogenic potential. We conducted studies to determine the effects of nitrofurantoin macrocrystals (Macrodantin, Norwich Eaton Pharmaceuticals, Inc.), a synthetic antibacterial, on reproductive capability, fetal development, and neonatal survival in the rat and the rabbit. Doses of 10.0, 20.0, and 30.0 mg/kg.d, approximately 2, 4, and 6 times the daily human therapeutic dose, were administered orally in a methylcellulose suspension to rats and rabbits in general reproduction, perinatal-postnatal, and teratology studies. Safety was assessed by evaluating reproductive capability, fertility, gestation period, fetal and neonatal death, litter size and viability, birth weight and postnatal growth, and malformations. Under the conditions of these studies, treatment with nitrofurantoin macrocrystals in rats and rabbits before or during pregnancy or during lactation caused no adverse effects in the mother, fetus, or neonate. These findings support the premise that nitrofurantoin macrocrystals constitute a safe treatment for urinary tract infection during pregnancy.

Abnormalities, Drug-Induced↗
PubMed1994

An endogenous circannual rhythm of reproduction in a tropical bat, Anoura geoffroyi, is not entrained by photoperiod.

Most species of mammals live in the tropics, and many breed seasonally, but little is known about the regulation of their seasonal cycles. Males of a tropical bat, Anoura geoffroyi (Order Chiroptera, Family Phyllostomidae), from 10 degrees latitude in Trinidad, were studied to test the role of photoperiod in regulating seasonal reproduction in the deep tropics. Groups of males were subjected to five treatments: 1) constant photoperiod; 2) a 12-mo cycle of civil twilight photoperiods mimicking those occurring at 10 degrees latitude; 3) civil twilight photoperiods of 10 degrees latitude, but accelerated to a 9-mo cycle; 4) civil twilight photoperiods characteristic of 30 degrees latitude, but accelerated to a 9-mo cycle; and 5) constant photoperiod, but with the timing of dark onset varied to match the timing of darkness at 10 degrees latitude, and accelerated to a 9-mo cycle. In all treatments, the first cycle of testis growth and regression matched that expected in the wild population, as reported previously for some of these groups. Subsequently, the testis cycle of bats in constant conditions free-ran for 20 mo with a peak-to-peak period of 7.3 +/- 0.3 mo. Period lengths in the four nonconstant groups, 7.2-7.7 mo, were not significantly different from that under constant conditions. Bats failed to entrain to any photoperiod cycle, including those mimicking changes at 10 degrees or 30 degrees latitude. They also failed to entrain to the cycle in which day length was held constant while time of sunset was varied, as occurs at the equator.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1979

Effects of the mycotoxin zearalenone on swine reproduction.

Concentrations of 25, 50, or 100 ppm of 95% purified zearalenone fed to groups of healthy, multiparous sows during preestrus or throughout the gestation period (or both) produced multiple reproductive deficiencies. These reproductive disorders included infertility, constant estrus, pseudopregnancy, diminished fertility, reduced litter size, smaller offspring, malformation, juvenile hyperestrogenism, and probably fetal resorption. Gross and histologic examinations of sows revealed lesions in the reproductive organs. Marked epithelial changes characterized by squamous metaplasia were noticed in the uterus, uterine duct, cervix, vagina, and mammary glands.

Animals↗
PubMed1988

Cluster headache in women: clinical findings and relationship with reproductive life.

Cluster headache (CH) occurs rarely among women; for this reason only a limited number of studies have been reported on the characteristics of the disease in the female population. In this study, 82 females (age range, 14-72 years) with episodic (69 cases) or chronic (13 cases) CH were investigated. The clinical features of headache and the physiologic events related to reproductive life were compared with those of various control groups. We did not find any remarkable differences in clinical features between men and women. Unlike other forms of primary headache, the course of CH does not seem to be modified by menstruation, pregnancy, or puerperium. Finally, our data seem to confirm a hypofertility trend, mostly after onset of CH, which had previously been noticed by other authors.

Adolescent↗
PubMed1984

Estradiol concentration in the serum of the one-humped camel (Camelus dromedarius) during the various reproductive stages.

During the estrous cycle of the camel the concentration of estradiol (E2) varies between 9 and 110 pg/ml. In early estrus, the peak level of E2 (74.7 +/- 6.61 pg/ml, n = 11) is maintained for 2.9 +/- 1.83 days. The length of an estrous cycle is 17.2 days. In the 10th month of pregnancy the level of E2 rises abruptly to 338.3 +/- 162.42 pg/ml and continues to rise until the 12th month, peaking at 606 +/- 120.27 pg/ml. The hormone concentration then drops until the day of parturition (mean 113.4 +/- 26.51 pg/ml). The level of E2 during the nonbreeding season (May-November) is low (6-48 pg/ml).

Animals↗
PubMed1999

Impact and reversibility of chronic ethanol feeding on the reproductive axis in the peripubertal male rat.

Teenage drinking continues to be a major problem in the United States as well as abroad. A significant depression in serum testosterone in adolescents who consume EtOH has been well described. In the male rodent model, a similar fall in testosterone has been reported, and prevention with the opiate blocker naltrexone has been demonstrated. To explore further the impact of chronic EtOH exposure on the reproductive axis in peripubertal rats, we designed this study specifically to define whether or not there was recovery after abstinence by examining reproductive hormones and their genes during and after EtOH exposure. Peripubertal male rats 35 d old were fed an EtOH-containing diet or a calorically matched control diet for 60 d. A third group was fed the control liquid diet ab libitum. EtOH was then withdrawn and all animals were fed standard rat chow and water ad libitum for an additional 3 mo. The EtOH-imbibing animals were found consistently to weigh less than their pair-fed mates and liquid diet ad libitum animals. Serum testosterone levels and testicular weights were significantly decreased by EtOH whereas serum estradiol levels were higher, suggesting enhanced peripheral conversion by EtOH. Spermatogenesis, assessed by histological parameters, was unaltered by EtOH. Serum luteinizing hormone levels were not different among the groups. Hypothalamic luteinizing hormone-releasing hormone mRNA levels were unaffected by EtOH. During the 3-mo recovery period, all the changes reversed, with a significant increase noted in testosterone. All other parameters remained the same among the groups. Thus, although chronic EtOH exposure in the peripubertal age period results in significant reproductive alterations, there is complete recovery on withdrawal.

Animals↗
PubMed1980

Effects of age, sex, and reproductive status on scent marking frequencies in the golden lion tamarin, Leontopithecus rosalia.

This study reports on the longitudinal changes in scent marking frequencies of male and female lion tamarins in relation to age, reproductive status, and group composition. Juvenile males and females in family groups and subordinate males in trios (2 males, 1 female) scent marked infrequently. Juvenile females scent marked less than juvenile males and began scent marking later. Adult pair-bonded males and females scent marked with similar frequencies. Females showed scent marking increases during mid-pregnancy, but their scent marking decreased both before and again after parturition. Both males and females exhibited decreases in scent marking while transporting dependent infants.

Age Factors↗
PubMed1984

Seasonal patterns of circulating progesterone and prolactin and response to bromocriptine in the female tammar Macropus eugenii.

Concentrations of prolactin and progesterone in the plasma of female tammars (Macropus eugenii) were measured during lactational quiescence and seasonal quiescence and during the period of natural resumption of reproduction after the summer solstice in December. Prolactin concentrations were consistently low (less than 40 ng/ml) during the period of declining day length and consistently elevated (greater than 40 ng/ml) during the period of increasing day length. Basal levels of progesterone were lowest (118.9 +/- 9.1 pg/ml) at the winter solstice and highest (244.1 +/- 21.0 pg/ml) at the summer solstice. Treatment with bromocriptine (CB154) did not depress prolactin levels at either time of the year but during February to June a single injection of 5 mg/kg body wt induced development of the quiescent corpus luteum (CL) and the diapausing embryo was reactivated. In February and March the level of progesterone increased in association with the developing CL, but after treatment at the winter solstice in June plasma progesterone did not increase although pregnancy was successfully completed. From September through November only 1 of 50 females responded to bromocriptine. None responded to bromocriptine given at the summer solstice in December, but all these animals spontaneously reactivated 2 weeks later. The difference in response of female tammars to bromocriptine treatment in the two halves of the year suggests that different endocrine controls operate in lactational and seasonal quiescence and that the latter is more complex.

Animals↗
PubMed1994

Ovarian derived prorenin-angiotensin cascade in human reproduction.

OBJECTIVE: To review the available literature concerning the renin-angiotensin system of the human and animal ovary and to outline the clinical relevance of this system. DESIGN: The location, function, and regulation of the components of the ovarian prorenin cascade are described. The possible functions of this system as well as its association with common gynecologic problems are also given. CONCLUSIONS: The ovary contains a complete cascade whose end product is the formation of angiotensin II. Angiotensin II may have a role in steroid synthesis, oocyte maturation, ovulation, and corpus luteum formation. Further, aberrations in this system are associated with ovarian tumors, ectopic pregnancy, pre-eclampsia, and ovarian hyperstimulation syndrome.

Angiotensin II↗
PubMed1992

Photoperiod-driven changes in reproductive function in male rhesus monkeys.

Environmental lighting, which regulates seasonal breeding in many animal species, has not been examined as a regulator of reproduction or puberty in man or nonhuman primates. In this study we examined the effects of controlled alternating long and short daily photoperiods, independent of other environmental variables, on testicular size and function in rhesus monkeys. Sixteen animals, some pubertal, others prepubertal, were individually caged indoors in light-controlled rooms. They were subjected to a 32-week "year" with alternating 16-week cycles of long (16 h of light and 8 h of darkness) or short (8 h of light and 16 h of darkness) days. Animals were examined every 2 weeks over four 32-week "years". Body weight, testicular diameter, and testicular volume were measured, and blood was collected for testosterone and PRL determinations. We found that although short days did not trigger testicular development in prepubertal animals, testicular growth was markedly enhanced by short days in postpubertal animals, accompanied by increased plasma testosterone levels and reduced PRL levels. In long days, testes regressed, testosterone levels fell, and PRL levels rose. The periodicity of testicular size, as determined by spectral analysis, showed a strong signal at a cycle length of 31 +/- 13 weeks, but no signal at intervals close to the natural 52-week year, indicating that the observed periodicity is induced by the changes in lighting, rather than by circannual changes in other variables. These studies establish that changes in photo-period alone can modulate reproductive function in a higher primate and suggest that the onset of puberty is not directly driven by seasonal fluctuations in day length.

Animals↗
PubMed2006

[The effects of flutamide on the full gene expression of early testis development of embryonic period male SD].

OBJECTIVE: To study the effects of Flutamide (Flu) on the full gene expression of early testis development of embryonic period in male SD rats. METHODS: Flu was injected subcutaneously (sc) with NS at doses of 6.25 mg/kg x d from 12th to 17th gestation days (GD), and in control group with tales doses NS. Fifty pregnant SD rats were sacrificed on GD 20. The mRNA were extracted respectively from fetus testis with treated and untreated Flu, then transcribed reversely to cDNA and labeled with cy5 and cy3 fluorescence. Subsequently, cDNA probes were hybridized to the Mouse40S cDNA microarray and fluorescence signals were analyzed. Meanwhile, we took out of the right testes of male offspring to make the detection of immunohistochemistry (IHC). Furthermore, we determined the level of testosterone by enzyme-linked immunosorbentassay (ELISA). RESULTS: Compared with the control group, a total of 31 identified genes expressed differently, including 14 down-regulated and 17 upregulated genes. However, the function of 5 down-regulated and 10 upregulated difference expression genes are unknown in Genbank. This finding has provided important reference basis for the molecular mechanism of reproductive development of Flu in the future. The activity of two important enzymes was cut down by IHC. The level of testosterone was decreased by ELISA. CONCLUSION: The results indicated that Flu administrated to F0 pregnant rats can damage apparently to the reproductive development of embryonic period male SD rats in many ways, and can cause the abnormality of sexual differentiation and sexual development in rats.

Androgen Antagonists↗
PubMed2005

11beta-hydroxysteroid dehydrogenase in the testis of Bufo arenarum: changes in its seasonal activity.

In rat Leydig cells, glucocorticoids (GC) inhibit testosterone (T) synthesis via glucocorticoid receptor (GR). However, GC access to GR is regulated by the local expression of 11beta-hydroxysteroid dehydrogenase (11beta-HSD). Two isoforms were identified in mammals: type 1, a NADP+-preferring enzyme with K(m) in the muM range for GC and type 2, NAD+-dependent, with K(m) in the nM range for GC. In amphibians, a seasonal rhythm in baseline GC levels was described. However, a shift in the amount of deactivating 11beta-HSD activity could alter GC effects. The purpose of this work is to describe seasonal changes in testicular activity of 11beta-HSD in Bufo arenarum as well as the annual and seasonal patterns of plasma corticosterone (B) and T. The activity of 11beta-HSD was assayed in homogenate and subcellular fractions in pre-reproductive (Pre-R), reproductive (R) and post-reproductive (Post-R) periods, using [3H]B. Plasma B and T were determined by RIA. Testicular 11beta-HSD is a microsomal NAD+-dependent enzyme with a K(m) in the nM order, its activity being strongly reduced by glycyrrhetinic acid. These results indicate that toad testes express an 11beta-HSD similar to mammalian type 2. Although 11beta-HSD activity is higher in the Post-R than in the R and Pre-R seasons (V(max): Pre-R: 0.26+/-0.10, R: 0.14+/-0.01, Post-R: 1.37+/-0.45, pmol/minmg protein), K(m) value remains constant throughout the year. A seasonal rhythm in baseline GC concentrations inversely correlated with plasma T was also described. T concentration is lower in the R season than in the other periods (Pre-R: 90+/-6; R: 12+/-1; Post-R: 56+/-3, nM) while total B concentration is higher in the breeding than in the other seasons (Pre-R: 62+/-10; R: 145+/-18; Post-R: 96+/-10, nM). Furthermore, free B (Pre-R: 51+/-8; R: 94+/-12; Post-R: 70+/-7, nM) was always below K(m) values. In conclusion, this work shows that the activity of 11beta-HSD in toad testes could modulate GC action by transforming active hormones in the corresponding inactive steroid.

11-beta-Hydroxysteroid Dehydrogenases↗
PubMed2006

A new perspective on management of reproduction in dairy cows: the need for detailed metabolic information, an improved selection index and extended lactation.

For lactating dairy cows, we need management tools, that are "clean, green and ethical", cost-effective and easy to use. Specific tools are needed for artificial insemination (AI) after oestrus detection within a few months of calving, and for managing the complex nutritional requirements of cows between successive calvings. Assessment of energy deficit by measurement of body condition score (BCS) has been useful in the past but we now need more sophisticated ways to measure the relationship between adipose tissue and fertility. For this reason, we have focused our attention on the cells of the adipose tissue, the adipocytes, and the role of the hormone that they produce, leptin. This hormone affects pulsatile LH release and, in dairy cows, it seems to be linked to the first postpartum ovulation. Adipocytes are always sensing energy status and they control leptin secretion dynamically, so blood leptin concentrations can change acutely, even when there is no detectable change in BCS. Leptin secretion seems to be determined by the secretory activity of each adipocyte as well as the total mass of adipocytes in the body of the animal (as measured by BCS). The strong relationship between BCS, leptin concentration and reproductive function in dairy cows suggests that we should reconsider the interval of the recovery from prepartum and postpartum damages, the need for high milk yields at the last lactation causing the dry-off stress and the subsequent troubles. We should also re-assess the current drive to reduce calving interval because milk yields during the early stages of lactation are economically very important but high yields seem to cause several metabolic and reproductive disorders in modern dairy cows. In general, the thinking has been that calving interval must be short because short intervals are more profitable. However, if we remember that main product from dairy cows is milk and that a short calving interval is very difficult without reproductive problems, then a longer calving interval might be more sensible and also more profitable. We have example of an extended calving interval in Japan, Supercows which are very rare cows yielding remarkable high milk. Finally, we probably need to improve dairy cows genetically if we are to achieve the goal of "clean, green and ethical" dairy farming. This paper reviews data relevant to these strategies and we conclude that more basic and applied research will be required if we are to find ways to reach that goal.

Animal Husbandry↗
PubMedDate not supplied

[The education for reproductive and sexual health of the pregnant adolescent].

The purpose of this article is to analyze the impact of an educational hospital based program. The objective of this program is to prompt attention to the adolescent population below 20 years old attending public hospitals to satisfy the lack of information on sexual and reproductive health. Emphasis is made in promoting the use of adequate family planning methods to enlarge the intergenesic periods in order to diminish reproductive risks. Recent evaluation reveals the main aspects in which education favorably influences the acquisition of knowledge about reproductive health within this age group.

Adolescent↗
PubMed2003

The effects of confinement environment on reproductive efficiency in the baboon.

Historically, to supply animals for medical research, both captive-bred baboons and imported wild-caught animals have been available. Now that imported animals are difficult to obtain, it is important to maximize domestic production. To this end, it is necessary to determine the optimum housing conditions (i.e., environmentally dependent factors) under which baboons have the greatest reproductive efficiency. At our institution, the Oklahoma University Health Sciences Center Primate Facility, we recently moved the majority of our baboon breeding colony into a large indoor-outdoor facility (El Reno) from a small, indoor facility (Annex). Fortuitously, this move allowed a direct comparison of baboon reproductive efficiency between the two radically different environments. The environment at the Annex is exclusively indoor and possesses limited but adequate living space (per Guide for the Care and Use of Laboratory Animals recommendations), whereas the El Reno environment is indoor-outdoor and naturalistic with living space exceeding Guide recommendations. Although we expected animals at the El Reno facility to exhibit somewhat increased reproductive efficiency, the magnitude of the increase was surprising: the mean number of days post-partum to first estrus was 165 for animals housed in the Annex, but 69 for those at the El Reno facility. In addition, the mean number of days from first estrus to conception was 61 for baboons in the Annex compared with 47 for those at El Reno, and the mean number of days from conception to next conception was 403 for animals in the Annex but 296 for those at El Reno. These results demonstrate that a change in housing environment can dramatically increase baboon breeding efficiency.

Animals↗