No abstract

For this study, we have determined the effects of neonatal leptin treatment on the evolution of body weight. Experiment 1: pups were divided into two groups: LepF - injected with leptin (8 micro g/100 g of body weight) for the first 10 days of lactation and control (C) - receiving saline. Experiment 2: pups were divided into two groups: LepL - injected with the same leptin concentration of experiment one for the last 10 days of lactation, and C, which received saline. Body weight and food intake were monitored until age 150 days, after which leptin concentrations were measured by ELISA. The LepF group had a significant increase in body weight (p < 0.05) from day 98 onward, in food intake (p < 0.05) from day 74 onward, and higher serum leptin concentration compared to the control (108 %, p < 0.05). The LepL group had a significant increase in body weight (p < 0.05) from day 113 onward, in food intake from day 121 onward (p < 0.001), and higher serum leptin concentration compared to controls (6.9 %, p < 0.05). These results suggest that both periods of lactation constituted a critical window for body weight and food intake programming, but the effects are more marked when the leptin is injected within the first ten days.

Some studies have shown that the mother's nutritional condition may influence offspring's endocrine function through metabolic imprinting. Recently, we showed that the kind of maternal malnutrition during lactation affects adult body weight of the offspring and it is related to milk composition. We studied lactating rats fed an 8 % protein-restricted diet (PR), a control 23 % protein diet (C), and an energy-restricted diet group (ER). After weaning, all animals received a normal diet until they were 180 days of age. At this time, the animals received a single i. p. injection of (131)I and were sacrificed 2 h after the injection. Total triiodothyronine (TT3) and total thyroxin (TT4) serum concentrations were measured by enzyme immunoassay. The PR group had significantly a higher thyroid (131)I uptake, TT3 serum concentration and in TT4 serum concentration, compared to the controls. The ER group had only significantly higher TT3 serum concentration. These results showed that thyroid function regulation in adulthood may depend on maternal nutritional condition during lactation. Probably, PR group had a high thyroid function, whereas the ER group only had an increase in the deiodination of T4. The hyperthyroidism in the PR group could explain the low body weight observed in those animals.

UA is a potential anti-diabetic agent with pharmacological properties for insulin resistance and diabetes therapy.

The goal of this study was to evaluate the effects of maternal malnutrition during lactation on serum levels of testosterone and estradiol, testicular testosterone concentration, aromatase, testicular androgen (AR) and estrogen a (ERa) receptors expression in the pups at weaning. From parturition until weaning, Wistar rats were separated into three groups: (C) control group, with free access to a standard laboratory diet containing 23% protein; protein-energy restricted (PER) group, with free access to an isoenergy and protein-restricted diet containing 8% protein; and energy-restricted (ER) group, receiving standard laboratory diet in restricted quantities, which were calculated according to the mean ingestion of the PER group. All pups were killed at weaning, corresponding to 21 days post partum. Compared with the C group, body weights (CZ48G2 . 3 g; PERZ20G1 . 3 g; ERZ25 . 4G0 . 9 g; P!0 . 01) and testicular weights (CZ0 . 15G0 . 02 g, PERZ0 . 05G0 . 01 g, ERZ0 . 06G 0 . 02 g, P!0 . 001) of both PER and ER groups were lower.However, there was no significant difference in the testicular/body weight ratio in PER and ER groups compared with the C group. The testosterone serum concentration (ng/ml) was significantly higher in the PER group compared with ER and C groups (CZ0 . 09G0 . 012; PERZ0 . 45G0 . 04; ERZ0 . 15G0 . 03, P!0 . 01). Testicular testosterone concentration (CZ2 . 1G0 . 43; PERZ6 . 5G0 . 7; ERZ13G2 . 3, P!0 . 01) was increased in treated groups when compared with controls. The estradiol serum concentration (pg/ml) was lower in both dietary groups (CZ74G 4 . 6; PERZ49G3 . 2; ERZ60G5 . 5, P!0 . 01). The amounts of aromatase mRNA and ERa transcripts were significantly lower (P!0 . 05) in PER and ER groups; conversely AR (both mRNA and protein) was significantly enhanced (P!0 . 05) in treated animals. The nutritional state in early phases of development is important since we have demonstrated here that the maternal malnutrition during lactation leads to alterations in estradiol and testosterone serum concentrations, testicular testosterone concentration, AR and ERa expression together with a decrease of aromatase expression. All together, these changes of steroid status may be deleterious for future germ cell development and reproductive function of these male pups submitted to early malnutrition.