Different Doses and Routes of Administration of Methimazole Affect Thyroid Status in Methimazole-induced Hypothyroidism in Rats.

OBJECTIVE: It is agreed that methimazole (MMI) can be administered to induce hypothyroidism. However, there are conflicting data about its effect on thyroid function and development in rats through different administrations. In the present study, we established and compared differences of the rat hypothyroid model induced by MMI added to drinking water or given through an intragastric tube. METHODS: Sixty-four male Wistar rats were randomly divided into seven groups. Methimazole was added to the drinking water (0.025%, 0.04% or 0.1% wt/vol), or through intragastric gavage (5 mg/100 g body weight (bw) or 8 mg/100 g bw) one time each day for 21 days. The rats were weighed every seven days. Blood samples were taken in order to detect the concentrations of serum triiodothyronine (T3), thyroxine (T4) and thyrotropin (TSH) at the end of the experiments. RESULTS: Our results indicate that the effect of methimazole on a rat's thyroid function and body weight is similar in both the group given 0.1% concentration in drinking water and the group which received 8 mg/100 g bw once daily through the intragastric tube. Also, a similar effect was observed in the 0.025%, 0.04% and 5 mg/100 g bw groups. CONCLUSION: These findings suggest that a relationship between the concentration of MMI by oral administration and the dose of it through intragastric administration could exist, and may contribute to inducing hypothyroidism in rats.

Association analysis between the OPG g.27667T>A genetic variant and bone mineral density in Chinese postmenopausal women.

The purpose of this study was to investigate the association of the g.27667T>A genetic variant in the osteoprotegerin (OPG) gene with bone mineral density (BMD) and osteoporosis. A total of 393 primary osteoporosis subjects and 402 healthy controls were recruited. The BMD of the femoral neck hip, lumbar spine (L2-4), and total hip were evaluated by Norland XR-46 dual-energy X-ray absorptiometry. The g.27667T>A genetic variant was genotyped using created restriction site-polymerase chain reaction. Our data indicated significant differences in BMD of the femoral neck hip, lumbar spine (L2-4), and total hip among different genotypes. Individuals with the genotype TT had significantly higher BMDs than those of genotypes TA and AA (P<0.05). Results from this study suggest that the g.27667T>A genetic variant in the OPG gene is potentially related to BMD and osteoporosis in Chinese postmenopausal women.

Sex differences in piercing-sucking sites on leaves of Ligustrum lucidum (Oleaceae) infested by the Chinese white wax scale insect, Ericerus pela (Chavannes) (Hemiptera: Coccidae).

The type of host tissues and cells ingested by piercing and sucking insects greatly affects their nutrient intake, which may subsequently affect insect fitness. This study describes the sex differences in feeding site selection between male and female nymphs of the Chinese white wax scale insect (CWWS), Ericerus pela (Chavannes), feeding on leaves of the Chinese privet, Ligustrum lucidum. Our data showed that the stylet tips of female nymphs terminated in the phloem sieve elements of main or lateral veins, while those of male nymphs terminated in the palisade parenchyma. We concluded that female nymphs fed from sieve elements and males fed from parenchyma cells. The potential impact of these feeding patterns was discussed in relation to the selection of a site for attachment, nutrient acquisition, and mouthpart stretching mechanism. Among these factors, selection of a site for attachment and mouthpart stretching mechanism may be the main cause of sex differences in feeding sites between female and male nymphs of CWWS.