Influence of cold exposure on dopamine content in rat brown adipose tissue.

Cold exposure produces a large increase in rat brown adipose tissue (BAT) dopamine (DA) content. This increase is rapid (30 min of cold are sufficient to produce a maximal effect), and can be detected at different ages (from birth to adulthood). Cold also greatly increases DA turnover rate in BAT.

[Quantitative histo-enzymological study of delta 5-3 beta-hydroxysteroid dehydrogenase activity in rat testis during the perinatal period. Relation with testicular crisis in the newborn rat].

The purpose of the present work was to determine if the neonatal testosterone surge in the rat (between 0 and 6 h after birth) was coincident with the histological and histochemical changes in the neonatal period. The histological study shows a decrease in the number of gonocytes and cells in mitosis. These observations are in good agreement with the results obtained by other authors.

Intermale aggression in mice: does hour of castration after birth influence adult behavior?

In the mouse, perinatally present testicular androgens promote the development of the propensity for adult intermale aggression. In the newborn male mouse plasma testosterone more than doubles during the first 2 h after birth and then falls rapidly to remain relatively low for the remainder of the 24-h period after birth. To study whether this surge in plasma testosterone influences aggressiveness we castrated some male mice within 1 h after birth i.

Striatal dopamine metabolism is differentially affected by insulin according to the genotype in Zucker rats: a microdialysis study.

The genetically obese Zucker rat presents several abnormalities related to insulin and brain monoamines, which may play a role in its impaired regulation of food intake and body weight. In a previous study, the possible insulin-monoamine interplay was investigated by measuring brain monoamine and metabolite levels in the three genotypes of the Zucker strain. In addition to the expected results, insulin had a particular effect on striatal dopamine (DA) release, regardless of ponderal status and genotype.

[Variations in the testicular response to HCG during the perinatal period in the rat: influence of estrogens].

The variations of the testicular responsiveness to hCG and the implication of the maternal estrogens in the functioning of the testes were studied in the perinatal male rat. Male rat fetuses treated with hCG at the end of gestation failed to show an increase in serum testosterone (T). The lack of testicular responsiveness to hCG in the fetus is neither due to anesthesia nor to a blocking effect of estrogens directly on the testes.

Changes in plasma testosterone levels during the peri-hatching period in the chicken.

Blood was obtained by heart puncture from 19-day-old Black Sex link chicken embryos and from Black Sex link chickens at 1.5, 6, or 24 h post-hatching. Plasma testosterone was determined by gas chromatography-mass spectrometry associated with stable isotope dilution.

The neonatal testosterone surge: a comparative study.

In the rat an abrupt discharge of testicular testosterone in the newborn male figures prominently in the development of mechanisms controlling gonadotropin secretion, sexual behavior, and also promotes the functional differentiation of the accessory sex glands. In this study we detail the temporal characteristics of this surge in the rat, and we provide comparative data documenting a similar surge-like appearance of testosterone in neonatal male mice, recently foaled male horses, and newborn human infants. Although the physiological and behavioral significance of this phenomenon for species other than the rat remains to be determined, the apparently ubiquitous appearance of the neonatal testosterone surge suggests that it may be of special significance in the sexual differentiation of many mammalian species.

Effects of insulin on brain monoamine metabolism in the Zucker rat: influence of genotype and age.

Disturbances of insulin or brain monoamine metabolism may play a role in the impaired regulation of food intake and body weight in the obese Zucker rat. We investigated a possible insulin-monoamine interaction by measuring monoamine levels in the hypothalamus and striatum of obese (fa-fa) and lean (Fa-Fa and Fa-fa) Zucker rats after peripheral insulin administration. The classically reported effects of insulin, i.

Sex differences in serum luteinizing hormone and testosterone in the human neonate during the first few hours after birth.

Blood was obtained from human male and female neonates within a few minutes after birth, and at intervals thereafter for up to 21 h. Serum LH was substantially higher at birth for boys than girls. For most boys, serum LH fell precipitously during the next hour; serum LH remained low for the remainder of the period sampled in both boys and girls.

Effects of insulin on brain serotonin in the young rat: influence of thyroid status.

Thyroid status has been shown to modify the adrenal catecholaminergic response to insulin. The influence of thyroid status on the brain serotonergic response to insulin is the subject of the present report. Newborn rats were divided into three groups: euthyroid, hypothyroid (propylthiouracil given to the suckling mother), and hypothyroid-treated with triiodothyronine (T3) as replacement therapy.

Testosterone levels in plasma and testes of neonatal mice.

Newborn female and male C57BL6 mice were decapitated at birth or at different times during the first 24 h after birth and testosterone was determined by radioimmunoassay in plasma and testes. In newborn females, plasma testosterone is low and does not significantly change over the first 24 h after birth. In contrast, in newborn males, plasma testosterone more than doubles during the first 2 h after birth and then falls rapidly to remain relatively low for the remainder of the 24 h period after birth.

Influence of the environmental temperature on the post-partum testosterone surge in the rat.

In the neonatal male rat, a rapid and transient increase in serum testosterone occurs about 2 h after birth. This post-partum testosterone surge (PPTS) has been implicated in the masculinization and defeminization of the central nervous system. The present study shows that environmental temperature can have a profound influence on the PPTS.

Effect of progesterone on the testosterone and estradiol levels in the hypothalamus of neonatal rats.

Pregnant female rats were injected with progesterone or oil from 18.5 up to 21.5 days of gestation.

Testicular hormones during the first few hours after birth augment the tendency of adult male rats to mount receptive females.

In the male rat, a dramatic increase in serum testosterone of testicular origin occurs during the first two hours of postnatal life. This experiment was designed to determine whether this increase contributes to the development of the propensity for adult male rats to mount sexually receptive females. Male rats were castrated at either 0-hours (virtually at the moment of birth), or at 6 hours, or at 24 hours after birth.

[Malaria, anemia and nutritional status: longitudinal study of their interaction in a sahelian zone (Senegal)].

Two villages in the sahelian zone of the Senegal river Basin, were surveyed during one year. On 5 occasions (May, July, October 1982, January, March 1983) 200 persons were clinically examined and a parasitological (parasite rate and specific antibodies), haematological and biochemical examination was done. At the same time an entomological survey was performed.

T-cell subsets and natural killer activity in Plasmodium falciparum-infected children.

Thirty children acutely infected by Plasmodium falciparum and suffering either benign uncomplicated malaria (17 cases), or cerebral malaria (13 cases), were investigated for T-cell number and subset distribution among peripheral blood mononuclear cells using OKT3, OKT4, and OKT8 monoclonal antibodies, and for natural killer (NK) activity using K562 cells as targets. They were compared to a group of 16 age- and sex-matched healthy Senegalese children. OKT8 cell percentage was found increased in both groups of patients with a decrease of OKT4 cell percentage in cerebral malaria patients only.

[Effect of newborn rat testes on the male sexual behavior of the testosterone-treated adult].

Neonatal male rats were castrated either at 0, 6 or 24 hrs. after birth. As adults, testosterone was delivered by subcutaneous implantation of a Silastic capsule containing this hormone.

[Influence of neonatal hypothyroidism on the response of the adrenal medulla of young rats to a physiological stimulation].

The adrenal medulla of control and hypothyroid young rats was stimulated through insulin hypoglycaemia. In the control animals, the intensity of the depletion of the adrenal epinephrine, which occurs in response to hypoglycaemia, increases up to 10 days of age. Neonatal hypothyroidism results in a retarded evolution.

[Antigenic specificity of antiplasmodium antibodies in an endemic area: an attempt at correlation with the induction of protective immunity].

Asexual blood-stage antigens from Plasmodium falciparum related to the development of protective immunity in an endemic area were identified by statistical comparison of antigens recognized by adult immune sera with those recognized by non-immune subjects (children). After metabolic labelling of parasites in culture and immunoprecipitation, target antigens of seric antibodies were separated by polyacrylamide gel electrophoresis/SDS and detected by fluorography. Two groups of antigens were thus identified: 1) the major bands, recognized by more than 90% of the sera regardless of the patients' immune status; and 2) the minor bands, less intense on fluorograms.

[Biochemical characterization and study of the sensitivity to Plasmodium falciparum infection. Apropos of a case of double CN Baltimore hemoglobinopathy discovered in Senegal].

The discovery of a double CNBalt hemoglobinopathy allowed the authors, after a family background investigation, to study the possible biological effects linked to that dual heterozygoty and to look for a protection against Plasmodium falciparum infections. It hasn't been possible to make evident any protection.

Gonadal steroid concentrations in serum and hypothalamus of the rat at birth: aromatization of testosterone to 17 beta-estradiol.

Endogenous concentrations of testosterone (T), 5 alpha-dihydrotestosterone, progesterone (P), and estradiol-17 beta (E2) were determined with specific RIAs in serum and hypothalami of male and female rats before, during, and up to 24 h after birth. In the male, a dramatic and transient increase in T concentration was observed in the serum and the hypothalamus between 0 h in utero and 2 h after delivery. At all times studied, T levels were undetectable in the female.

Adrenal dopamine-beta-hydroxylase activity in the ground squirrel Citellus citellus--effect of hibernation, arousal, and continuous light.

In the hibernating ground squirrel activity of adrenal dopamine-beta-hydroxylase was significantly lower as compared with the active animals (P less than 0.01). The highest activity of this enzyme was found in animals tested immediately after arousal from hibernation (P less than 0.

Female sexual behavior in male rats: effect of hour of castration at birth.

In the male rat, a dramatic increase in serum testosterone occurs during the first four hours of postnatal life. The experiments sought to determine whether such an increase would participate directly on the defeminization process. Newborn male rats were castrated either at 0 hr in utero (literally at the moment of birth) or at 6 or 12 hrs after birth.

Hypothalamic testosterone increase in the male rat at birth.

In the male rat, a dramatic increase in serum testosterone occurs during the first 2 h of postnatal life. Since the hypothalamus is known to be an important site for sexual differentiation of the brain, this early testosterone surge was a good model to use to study the transfer of serum testosterone to the hypothalamus and cerebral cortex. Endogenous testosterone was measured by radioimmunoassay in the hypothalamus and the cerebral cortex of the foetus and newborn rats during the first 6 h following birth.