Delayed Postnatal Growth and Anterior Pituitary Development in Growth-Retarded (grt) Female Mice
Autor: | Kenichi Kobayashi, Kazutoshi Yamamoto, Takeo Machida, Sakae Kikuyama, Tetsuya Kobayashi, Yukinobu Tanaami |
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Rok vydání: | 2021 |
Předmět: |
0106 biological sciences
0301 basic medicine endocrine system medicine.medical_specialty endocrine system diseases medicine.drug_class Biology 010603 evolutionary biology 01 natural sciences 03 medical and health sciences Anterior pituitary Internal medicine medicine Estrous cycle Thyroid medicine.disease Prolactin Growth hormone secretion Congenital hypothyroidism 030104 developmental biology medicine.anatomical_structure Endocrinology Estrogen Animal Science and Zoology hormones hormone substitutes and hormone antagonists Hormone |
Zdroj: | Zoological Science. 38 |
ISSN: | 0289-0003 |
Popis: | Growth-retarded (grt) mice display primary congenital hypothyroidism due to the hyporesponsiveness of their thyroid glands to thyroid-stimulating hormone (TSH). We examined somatic growth, anterior pituitary development, and hormonal profiles in female grt mice and normal ones. Although growth in grt females was suppressed 2 weeks after birth, the measured growth parameters and organ weights gradually increased and finally reached close to the normal levels. Grt mice exhibited delayed eye and vaginal openings and remained in a state of persistent diestrus thereafter, plasma estrogen levels being lower than those in normal mice. Grt mice that received normal-donor thyroids showed accelerated growth and their body weights increased up to the sham-normal levels, indicating the importance of early thyroid hormone supplementation. In the anterior pituitary, there were fewer growth hormone (GH) and prolactin (PRL) cells in grt mice than in normal mice as examined at 12 weeks after birth, but the numbers of these cells did not differ from those in normal mice after 24 weeks. Grt mice had more TSH cells than normal mice until 48 weeks. Plasma GH levels in grt mice were lower than those in normal mice at 2 weeks, but did not differ substantially after 5 weeks. Compared with normal mice, grt mice had significantly lower plasma PRL and thyroxine levels, but notably higher TSH levels until 48 weeks. These findings indicate that thyroid hormone deficiency in grt mice causes delayed development and growth, and inappropriate development of GH, PRL and TSH cells, followed by the abnormal secretion of hormones by these pituitary cells. |
Databáze: | OpenAIRE |
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