Mandible analysis in sex steroid-deficient rats.

The aim of this study was to evaluate, by morphologic techniques, the effects of sex steroid deficiency on mandible bone remodeling of female rats, in groups of different experimental periods and to compare the results with 90-day orquiectomized males. Female and male Wistar rats, 3 months old, were divided into experimental groups and at the end of each experimental period were killed, and mandibles were extracted. The left mandibles were prepared with rote technique bone and examined by a light microscope. Morphological analyses of the mandibles demonstrated resorption signals in the alveolar bone, after 30 days in ovariectomized females, but it was more intense 90 days after castration. The orquiectomized group exhibited some signals of resorption similar to the ovariectomized group of 60 days. Morphometric analysis of alveolar bone thickness in females after 60 days was in agreement with morphological results. However, the analysis of periodontal ligament thickness did not show any significant difference. There were variations in sexual hormone deficiency in the mandibles of males and females and they seemed to be more precocious in ovariectomized than in orquiectomized rats. It is important for a health professional to have knowledge about bone metabolism to improve the quality of life of postmenopaused and old people.

Is the infertility in hypothyroidism mainly due to ovarian or pituitary functional changes?

The objective of the present study was to examine whether hypothyroidism affects the reproductive system of adult female rats by evaluating ovarian morphology, uterus weight and the changes in serum and pituitary concentrations of prolactin and gonadotropins. Three-month-old female rats were divided into three groups: control (N = 10), hypothyroid (N = 10), treated with 0.05 percent 6-propyl-2-thiouracil (PTU) in drinking water for 60 days, and T4-treated group (N = 10), receiving daily sc injections of L-thyroxine (0.8 æg/100 g body weight) during the last 10 days of the experiment. At the end of 50 days of hypothyroidism no hypothyroid animal showed a regular cycle, while 71 percent of controls as well as the T4-treated rats showed regular cycles. Corpora lutea, growing follicles and mature Graafian follicles were found in all ovaries studied. The corpora lutea were smaller in both the hypothyroid and T4-replaced rats. Graafian follicles were found in 72 percent of controls and only in 34 percent of hypothyroid and 43 percent of T4-treated animals. Serum LH, FSH, progesterone and estradiol concentrations did not differ among the three groups. Serum prolactin concentration and the pituitary content of the three hormones studied were higher in the hypothyroid animals compared to control. T4 treatment restored serum prolactin concentration to the level found in controls, but only partially normalized the pituitary content of gonadotropins and prolactin. In conclusion, the morphological changes caused by hypothyroidism can be a consequence of higher prolactin production that can block the secretion and action of gonadotropins, being the main cause of the changes observed

Is the infertility in hypothyroidism mainly due to ovarian or pituitary functional changes?

The objective of the present study was to examine whether hypothyroidism affects the reproductive system of adult female rats by evaluating ovarian morphology, uterus weight and the changes in serum and pituitary concentrations of prolactin and gonadotropins. Three-month-old female rats were divided into three groups: control (N = 10), hypothyroid (N = 10), treated with 0.05% 6-propyl-2-thiouracil (PTU) in drinking water for 60 days, and T4-treated group (N = 10), receiving daily sc injections of L-thyroxine (0.8 microg/100 g body weight) during the last 10 days of the experiment. At the end of 50 days of hypothyroidism no hypothyroid animal showed a regular cycle, while 71% of controls as well as the T4-treated rats showed regular cycles. Corpora lutea, growing follicles and mature Graafian follicles were found in all ovaries studied. The corpora lutea were smaller in both the hypothyroid and T4-replaced rats. Graafian follicles were found in 72% of controls and only in 34% of hypothyroid and 43% of T4-treated animals. Serum LH, FSH, progesterone and estradiol concentrations did not differ among the three groups. Serum prolactin concentration and the pituitary content of the three hormones studied were higher in the hypothyroid animals compared to control. T4 treatment restored serum prolactin concentration to the level found in controls, but only partially normalized the pituitary content of gonadotropins and prolactin. In conclusion, the morphological changes caused by hypothyroidism can be a consequence of higher prolactin production that can block the secretion and action of gonadotropins, being the main cause of the changes observed.