Abstract The risk of pregnancy loss in mares leads to the use of exogenous hormones to help pregnancy maintenance. The objective was to evaluate the proportion of thyroid hormones and steroids in neonates, in the following postpartum period, born to mares fed with synthetic progesterone and to verify the existence of a correlation between the level of progesterone between mother and neonate. Twenty-seven mares and their foals were used. The animals were divided into 5 experimental groups: group 1 (control, without hormonal supplementation), group 2 (random samples fed to 120 days of pregnancy with long-term progesterone), group 3 (mares fed with short-term progesterone as of 280.º day of pregnancy), group 4 (mares fed with long-term progesterone as of 280.º day of pregnancy) and group 5 (mares fed with synthetic hormone [altrenogest] as of 280.º day of pregnancy). The animal’s blood collection took place immediately after parturition for the hormonal measurement. The hormones measured in neonates were total T3, free T4, TSH, progesterone and cortisone. In mares, only levels of progesterone. The groups of neonates showed no difference on levels of total T3, free T4, TSH and progesterone. There was no difference on levels of progesterone in mares among the groups. Neonates from groups 4 and 5 had higher and lower cortisone levels, respectively. No neonate showed clinical change. There was also no correlation between levels of progesterone in mares and foals. Thus, hormonal supplementation with long-term progesterone as of 280 days of pregnancy leds to an increase in the neonate's cortisone levels, in the meantime, supplementation with altrenogest as of 280 days of pregnancy caused a decrease on cortisone levels in foals, despite clinical signs have not been observed on these animals.

This study investigated the effects of perinatal cadmium exposure on sexual behavior, organ weight, and testosterone levels in adult rats. We examined whether immediate postpartum testosterone administration is able to reverse the toxic effects of the metal. Forty pregnant Wistar rats were divided into three groups: 1) control, 2) 10 mg kg-1 cadmium chloride per day, and 3) 20 mg kg-1 cadmium chloride per day. These dams were treated on gestational days 18 and 21 and from lactation 1 to 7. Immediately after birth, half of the offspring from the experimental and control groups received 50 μl (i.p.) of 0.2% testosterone. Male sexual behavior, histological analysis and weight of organs as well as serum testosterone levels were assessed. Results showed that both cadmium doses disrupted sexual behavior in male rats, and postnatal treatment with testosterone reversed the toxic effects of 10 mg kg-1 cadmium and attenuated the effects of 20 mg kg-1 cadmium. Body weight and absolute testis, epididymis, and seminal vesicle weight were decreased by the higher cadmium dose, and testosterone supplementation did not reverse these effects. Serum testosterone levels were unaffected by both cadmium doses. No histological changes were detected in all organs analyzed. Maternal cadmium exposure effects in sexual parameters of male rat offspring were explained by the altered masculinization of the hypothalamus. We suggest that cadmium damaged cerebral sexual differentiation by its actions as an endocrine disruptor and supported by the changes discretely observed from early life during sexual development to adult life, reflected by sexual behavior. Testosterone supplementation after birth reversed some crucial parameters directly related to sexual behavior.

No presente trabalho, foram utilizadas 21 fêmeas suínas, virgens, sexualmente aptas, criadas e mantidas sob condições industriais, para observação dos perfis hormonais séricos de triiodotironina e tiroxina, durante o ciclo estral. As colheitas de sangue foram efetuadas sempre no mesmo intervalo, entre 8 e 10 horas. Cada animal foi submetido a 14 punções venosas, distribuídas nos dias zero, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 21, 22 e 23 do ciclo estral. Consideramos o dia zero como o primeiro dia da fase estral, e o 23º dia como o primeiro do estro subseqüente. Os ensaios para dosagens hormonais foram executados utilizando-se a técnica de radioimunoensaio (RIE) em fase sólida e para isso foi empregado conjunto de reagentes comerciais (Coat-A-Count®). Para o hormônio triiodotironina foram observados valores altos no 1º e 23º dia e valor mínimo no 12º dia do ciclo estral. O hormônio tiroxina apresentou valores que oscilaram entre 2,42 e 3,74 mig/dl.

In the present study 21 young female swines, sexually mature, reared and kept under a industrial management system were assessed for its progesterone serum profiles during the oestrus cycle. Blood sampling was performed always at the same interval, from 8:00 to 10:00 AM. Each animal was submitted to 14 venal punctions at days 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 21, 22 and 23 of the oestrous cycle. the first day of the oestrous phase was assumed to be Day 0 and the 23rd as the first of the next cycle. Hormone determinations were performed employing a solid phase radioimmunoassay (RIA). Highest T3 concentrations were observed at the 1st and 23rd days and minimul values for the 12hd of the oestrus cycle. Regarding T4, the concentration values ranged from 2.42 and 3.74 mug/dl.

No presente trabalho foram utilizadas quatro fêmeas suínas, adultas, mestiças, não-gestantes e sem sinais clínicos de estro, criadas e mantidas sob condições industriais de criação. Objetivou-se avaliar a ocorrência de ritmicidade biológica circadiana para tiroxina e 17-alfa -OH progesterona. Os ensaios para dosagens hormonais foram executados utilizando-se a técnica de radioimunoensaio (RIE) em fase sólida e para isso foi empregado conjunto de reagentes comerciais (COAT-A-COUNT R). As análises séricas de tiroxina mostraram valores mais elevados ao redor das 15 horas, decrescendo a partir dai até atingir níveis menores no intervalo da zero às 4 horas. Quanto a 17-alfa -OH progesterona, observaram-se níveis mais elevados por volta das 3 horas, decrescendo gradativamente ao longo do dia, até atingir menor concentração no intervalo das 12 às 15 horas.

Aiming at the evaluation of the occurrence of thyroxine and progesterone-17-alpha-OH circadian rhythm, 4 adult crossbred swine females (non-pregnant and showing no estrous signs) were studied, reared and kept under a industrial management system. Hormone determinations were assessed by solid phase radioimmunoassay (RIA)ª. Thyroxine serum analysis showed the highest concentrations around 3:00 PM and decreased until reaching the lowest values at the 0:00 to 4:00 AM interval. Regarding progesterone-17-alpha-OH, the highest concentrations were observed at 3:00 AM, showing a progressive decrease along the day until reaching lower values at the 12:00 to 3:00 PM interval.

No presente trabalho, foram utilizadas 21 fêmeas suínas, virgens, sexualmente aptas, criadas e mantidas sob condições industriais, para observação dos perfis hormonais séricos de 17-alfa-OH progesterona e androstenediona, durante o ciclo estral. As colheitas de sangue foram efetuadas sempre no mesmo intervalo, entre 8 e 10 horas. Cada animal foi submetido a 14 punções venosas, distribuídas nos dias zero, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 21, 22 e 23 do ciclo estral. Considerou-se o dia zero como o primeiro dia da fase estral, e o 23º dia como o primeiro do estro subseqüente. Os ensaios para dosagens hormonais foram executados utilizando-se a técnica de radioimunoensaio (RIE) em fase sólida e para isso foi empregado conjunto de reagentes comerciais (Coat-A-Count®). Para o hormônio 17-alfa-OH progesterona, foram encontrados valores médios que variaram entre 0,18 e 2,7 ng/ml e para o hormônio androstenediona esses valores oscilaram entre 0,08 e 0,24 ng/ml.

In the present study 21 young female swines, sexually mature, reared and kept under a industrial management system were assessed for their progesterone serum profiles during the oestrus cycle. Blood sampling was performed always at the same interval, from 8:00 to 10:00 AM. Each animal was submitted to 14 venal punctions at days 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 21, 22 and 23 of the oestrous cycle. the first day of the oestrous phase was assumed to be Day 0 and the 23rd as the first of the next cycle. Hormone determinations were performed employing a solid phase radioimmunoassay (RIA). For progesterone 17-alpha-OH hormone, the observed mean values ranged from 0.18 to 2.7 ng/ml and for the androstenedione hormone those values ranged from 0.08 to 0.24 ng/ml.