Norepinephrine methylation in fetal rat adrenals.

The activity of phenylethanolamine-N-methyl transferase, the enzyme that methylates norepinephrine to form epinephrine, increases rapidly in the fetal rat adrenal during the day preceding epinephrine accumulation. The developmental increase in enzyme activity and the accumulation of epinephrine are prevented by fetal hypophysectomy (decapitation). Administration of adrenocorticotrophic hormone or cortisol acetate largely reverses the effect of fetal decapitation.

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. We failed to detect any significant 5 alpha-dihydrotestosterone levels in the serum and the hypothalamus of both sexes. Serum E2 levels decreased between the 21-day fetal stage and 24 h postpartum. However, in males, hypothalamic E2 dramatically increased between 0 h in utero and 1 h after delivery and decreased between 2 and 24 h. This surge was absent in females and males gonadectomized at 0 h, suggesting that this surge is linked to the presence of the testes. E2 was undetectable in the cerebral cortex. P presented the same pattern of declining levels in the male and the female, and no sex difference was noted for the mean concentrations in the serum or the hypothalamus. The fall in P levels and the sudden increase in hypothalamic T and E2 levels could be determinant factors in the initiation of central nervous system sexual differentiation in the rat. The fact that in the male rat, hypothalamic E2 increases during the time when testicular secretions defeminize the brain strengthens the view that E2 mediates some of the effects of T.

Changes in testicular weight and serum gonadotropin and testosterone levels before, during, and after birth in the perinatal rat.

Changes in serum and pituitary LH and FSH concentrations have been measured in the newborn male rat before, during, and up to 24 h after birth. A sudden and transient increase of serum and pituitary gonadotropins is observed at birth, which is followed by a rapid increase of absolute and relative testicular weights between 2--12 h (P less than 0.0001) and by a transient increase of serum testosterone between 0 h in utero (810 +/- 26 pg/ml) and 2 h (2820 +/- 318 pg/ml; P less than 0.0001). Similarly, premature newborn rats obtained by cesarian delivery on day 20 of gestation also exhibited an increase in testicular weight between 0--6 h and an increase in serum testosterone levels between 0 h (730 +/- 170 pg/ml) and 2 h (3400 +/- 300 pg/ml; P less than 0.001) with only a slight increase in serum LH. These results show that the hypophyseo-testicular axis of the rats is stimulated at the moment of birth. The factors responsible for this stimulation are discussed. This transient testicular crisis occurring at birth could affect the process of masculinization of the central nervous system of the rat.

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. In girls, serum testosterone was low at birth and remained low for at least 21 h. At birth, serum testosterone in boys was higher than for girls, increased dramatically during the first 3 h after birth, and remained elevated (2 to 3 times higher than for girls) between 3 and 12 h after birth. In newborn human males, a sudden discharge of hypophyseal LH appears to stimulate neonatal secretion of testosterone by the testes. The functional significance of this phenomenon remains to be determined.

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. At 14 days of age, the animals in each group received either insulin (10 IU/kg SC) or saline. Levels of serotonin (5-HT) and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) were determined in several brain regions. Hypothyroidism induced increases in hypothalamic 5-HT and 5-HIAA and in cortical 5-HIAA levels. The elevations in 5-HIAA levels were reversed by T3. Insulin treatment-induced increases in 5-HIAA levels in all brain regions of both the hypothyroid and the T3-replaced rats. Thyroid status thus influences the serotonergic response to insulin in the young rat, but contrary to what occurred in adrenals for catecholamines, hypothyroidism enhances the central serotonergic response to insulin.

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. We further investigated this point in the present study, using the brain microdialysis technique in the striatum. Lean homozygous Fa-Fa rats responded as expected to insulin with regard to striatal DA release, with increases in DA and 3-methoxy-tyramine levels and decreases in dihydroxyphenylacetic acid and homovanillic acid. Lean heterozygous Fa-fa rats showed a very specific response profile, with decreases in all dopaminergic parameters, suggestive of an effect on DA synthesis rather than DA release. This further emphasizes the marked differences between homozygous and heterozygous lean rats. The obese fa-fa rats clearly fell into two populations. The first showed a profile of response to insulin similar to that of the lean Fa-fa rats, in keeping with the disturbances related to the "fa" gene. The second showed an increase in all the dopaminergic parameters. This pattern of response was, however, different from that of the Fa-Fa rats. These opposing responses in the two obese populations did not reflect differences in the blood glucose response to insulin. One explanation is that 16 wk may be a critical transition period in the development of genetic obesity, with regard to brain monoamine disturbances and the response to insulin.

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.e., increases in tryptophan, 5-hydroxy-indolacetic acid (5-HIAA) and dihydroxyphenylacetic acid (DOPAC) levels, were observed in the hypothalamus of Fa-Fa and Fa-fa rats, but not in obese fa-fa rats. Given the mechanism of action of insulin, this lack of effect in the obese rats may be related to the peripheral insulin resistance they exhibit. Furthermore, given the role of these monoaminergic systems, this reduced effect may be related to the impaired regulation of food intake and body weight. At 8 wk of age, however, insulin restored the decreased basal 5-HIAA levels observed in the obese rats. Increase in 5-HIAA levels following insulin administration appeared in the striatum of Fa-Fa rats only, suggesting that, as for brain insulin content, other central insulin-related disturbances may be related to the presence of the "fa" gene. In addition, certain effects of insulin on striatal dopamine release were observed in only the Fa-Fa and fa-fa rats, suggesting a particular disturbance related to the heterozygous character. This latter point calls for further investigations on the central dopaminergic effects of insulin.

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. At 19 days the plasma of male and female chick embryos contains measurable amounts of testosterone and levels do not differ between sexes. After hatching plasma testosterone gradually declines from pre-hatch concentrations in males and females, but in all the post-hatch ages studied, plasma testosterone was significantly higher in male than in female chicks. These results indicate that in male chickens, contrary to mammals at birth, there is no surge in plasma testosterone at hatching.

Detection of circulating antibodies in cutaneous leishmaniasis by enzyme-linked immunosorbent assay (ELISA).

An immunoenzymatic diagnostic technique applicable to cutaneous leishmaniasis is described. The antigen used (Leishmania tropica major) was equally useful in diagnosing visceral and mucocutaneous forms of the disease. The criteria for positivity were defined by using groups of negative controls, and the specificity of the reaction was evaluated by using sera from patients with various diseases. Among these, sera from patients with lepromatous leprosy, tuberculosis, or African trypanosomiasis strongly cross-reacted with leishmania antigen. Examining serial dilutions of the sera facilitated the interpretation of the results and eliminated a significant percentage of false positives.

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. In the male, hypothalamic testosterone increased between 0 h in utero and 2 h; in the males gonadectomized at 0 h in utero and killed at the age of 2 h, the testosterone surge was abolished, clearly indicating the testicular origin of this hormone in the neonate. The small testosterone increase in the cerebral cortex compared with that in the hypothalamus reflects a preferential uptake of this hormone by the hypothalamus of the newborn. In the female, hypothalamic testosterone slightly decreased between 0 h in utero and 6 h. These results are in agreement with the view that hypothalamic modifications form the basis for some behavioral and physiological changes attributed to the effect of perinatal hormonal stimulation.

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. Some males were castrated at 0 hr in utero and injected at the time of surgery with 1 or 5 micrograms testosterone propionate (TP). At about 90 days of age, each animal was injected with estrogen and progesterone and tested for female sex behavior. Males castrated at 0 hr in utero displayed typical female sex behavior. Males castrated at 6 or 12 hrs after birth were less receptive than males castrated at 0 hr. Males castrated at 0 hr and injected with testosterone at this time almost never showed lordosis as adults after treatment with ovarian hormones. These results are consistent with the idea that the rapid elevation in serum testosterone which occurs shortly after birth suppresses the development of sexual behavior sensitivity to ovarian hormonal stimulation.

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.e., before the surge. We castrated other males between 1.5-6 h after birth, or 1, 6, or 12 days after birth. Males were given testosterone as adults and tested for aggression for 5 weeks. Males castrated within 1 h after birth were not clearly different from males castrated 1.5-6 h after birth with respect to aggressive behavior, although males in both groups were substantially less aggressive than males castrated later in life. Thus, the perinatal surge in plasma testosterone in the mouse does not appear to make a unique contribution to the organization of mechanisms for intermale aggression. Rather, this surge is probably the initial stimulus that begins the postnatal process by which testicular hormones promote the development of the potential for adult aggressive behavior. This process appears to be complete by 6 days after birth.

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. Some males castrated at 0-hours were injected with 1 microgram of testosterone after surgery. Control males were sham-operated at birth, and castrated in adulthood. At about 90 days of age, each male was given testosterone replacement therapy and tested over a period of 6 weeks for mounting. Castration of newborn males retards the development of mounting in the sense that males castrated at 0-hours require a longer period of hormone stimulation before beginning to mount, a greater percentage of males castrated at 0-hours fail to mount altogether, and even those who do mount do so at a frequency significantly lower than that for males castrated later in life. These effects are not seen when males are given an injection of testosterone immediately after castration at 0-hours, or when castration occurs at 6 hours after birth or later. We conclude that gonadal hormonal stimulation during the first several hours after birth contributes to, although is perhaps not essential for, the development of mounting.

Antibody to hepatitis B virus surface and core antigens in Gambia pouched rats (Cricetomys Gambianus).

Sera from 108 Cricetomys gambianus (Gambia pouched rat) were investigated for HBV and HAV serum markers. 42.6% of them evidenced anti-HBs and 12.0% anti-HBc. HBs Ag was never detected. The most probable hypothesis is that these animals were infected with a new virus related to HBV.

[Laryngeal histoplasmosis due to "Histoplasma duboisii" (author's transl)]. / Histoplasmose laryngée à "Histoplasma duboisii".

Primitive detection of the Histoplasma duboisii accompanied with proteiform manifestations, is rare in the superior air ways. Its localisation at the larynx level is an exception and makes the very interest of our following reported observation. In front of this hard diagnostic, only the pathogenic agent visualisation gives evidence. Among serological techniques, immuno-fluorescence and E.L.I.S.A. are very helpful. Therapeutic possibilities have been improved by Miconazole which both associates efficiency and inocuity.

[A study by gas-liquid chromatography of the urinary excretion of neutral 17 oxosteroids in healthy Senegalese adults (author's transl)]. / Etude par chromatographie gaz-liquides de l'élimination urinaire des 17 oxostéroïdes neutres chez le sénégalais adulte sain.

The urinary excretion of neutral 17 oxosteroïds has been determined by gas-liquid chromatography on 60 healthy ambulatory senegalese adults of both sexes. Except 11 beta hydroxyandrosteron, all fractions are lower than those usually found among european people.

[HBs antigen in rural population of Senegal (author's transl)]. / Antigene HBs dans les populations rurales du Senegal.

The prevalence of HBs Ag has been determined by counter-immuno-electrophoresis among 16,006 Africans of all ages and both sexes living in 132 villages chosen at random in whole Senegal. 8,83 +/- 0,5 p. 100 of the examined people were positive for HBs Ag. HBs Ag is much more frequent among males (11,1 p. 100) than females (7,0 p. 100). Almost non existent before the age of 1, prevalence increases during childhood and reaches its summit between 10 and 14 years for boys (14,7 p. 100) and between 20 and 24 for women (10,1 p. 100), then it decreases regularly with old age and become negligible over 60. Ethnic factors and way of living are more important than geographical factors. Subtyping demonstrated the importance of contamination inside families and consequently the preponderance of oral over percutaneous transmission.