Data/hora: 01/06/2024 05:33:12

Provedor de dados: | 56
País: | Brazil
Título: | Is the infertility in hypothyroidism mainly due to ovarian or pituitary functional changes?
Autores: | Armada-Dias,L.; Carvalho,J.J.; Breitenbach,M.M.D.; Franci,C.R.; Moura,E.G.
Data: | 2001-09-01
Ano: | 2001
Palavras-chave: | Hypothyroidism; Prolactin; Gonadotropins; Folliculogenesis; Estrous cycle.
Resumo: | 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 µg/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.
Tipo: | Info:eu-repo/semantics/article
Idioma: | Inglês
Identificador: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2001000900015
Editor: | Associação Brasileira de Divulgação Científica
Relação: | 10.1590/S0100-879X2001000900015
Formato: | text/html
Fonte: | Brazilian Journal of Medical and Biological Research  v.34 n.9 2001
Fonte: | info:eu-repo/semantics/openAccess