Short term hypothyroidism affects ovarian function in the cycling rat

Reproductive Biology and Endocrinology

Research

Carlos Gamarra-Luques¹  Graciela A Jahn²  María Belén Hapon³ 

[1] Instituto de Ciencias Básicas, Universidad Nacional de Cuyo, Mendoza, Argentina;Instituto de Embriología e Histología, IHEM-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina;Laboratorio de Reproducción y Lactancia, IMBECU-CONICET, Mendoza, Argentina;Laboratorio de Reproducción y Lactancia, IMBECU-CONICET, Mendoza, Argentina;Instituto de Ciencias Básicas, Universidad Nacional de Cuyo, Mendoza, Argentina;

关键词: Growth Hormone;    Hypothyroidism;    Luteinizing Hormone;    Granulosa Cell;    Follicle Stimulate Hormone;   

DOI  :  10.1186/1477-7827-8-14

 received in 2009-10-11, accepted in 2010-02-11,  发布年份 2010

来源: Springer

【 摘 要 】

BackgroundRats made hypothyroid with propilthyouracil start showing abnormal cycling on the second cycle after the start of the treatment, with a high proportion of spontaneous pseudopregnancies and reduced fertility.MethodsTo investigate some of the mechanisms involved in these reproductive abnormalities, hypothyroidism was induced in virgin rats by propilthyouracil (0.1 g/L in the drinking water) and we determined circulating hormones by radioimmunoassay and whole ovary expression of ovarian hormone receptors, growth factors and steroidogenic enzymes using semi-quantitative RT-PCR.The study was performed on days 6 to 9 of treatment, corresponding to diestrus I (at 20.00-22.00 h), diestrus II (at 20.00-22.00 h), proestrus and estrus (both at 8.00-10.00 h and 20.00-22.00 h) of the second estrous cycle after beginning propilthyouracil treatment. Another group of rats was mated on day 8 and the treatment continued through the entire pregnancy to evaluate reproductive performance.ResultsHypothyroidism increased circulating prolactin and estradiol on estrus 5 to 7-fold and 1.2 to 1.4-fold respectively. Growth hormone and insulin-like growth factor 1 diminished 60 and 20% respectively on proestrus morning. Hypothyroidism doubled the ovarian mRNA contents of estrogen receptor-beta on proestrus and estrus evenings, cyp19A1 aromatase mRNA on estrus evening and of growth hormone receptor on proestrus evening. Hypothyroidism did not influence ovulation rate or the number of corpora lutea at term, but a diminished number of implantation sites and pups per litter were observed (Hypothyroid: 11.7 +/- 0.8 vs. Control: 13.9 +/- 0.7).ConclusionsShort term hypothyroidism alters normal hormone profile in the cycling rat increasing the expression of estrogen receptor-beta and cyp19A1 aromatase on estrus, which in turn may stimulate estradiol and prolactin secretion, favouring corpus luteum survival and the subsequent instauration of pseudopregnancy.

【 授权许可】

Unknown   
© Hapon et al; licensee BioMed Central Ltd. 2010. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.