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Pituitary morphology in anencephalic human fetuses
D Pilavdzic1, K Kovacs, S L Asa
1Department of Pathology, Mount Sinai Hospital, Ontario, Canada.
Neuroendocrinology
|March 1, 1997
Summary
Anencephalic fetuses show that pituitary cells can develop without a hypothalamus. However, hypothalamic factors are crucial for maintaining certain pituitary cell types, impacting hormone production.
Area of Science:
- Developmental biology
- Endocrinology
- Neuroscience
Background:
- The hypothalamus plays a critical role in regulating pituitary gland development and function.
- Anencephaly, a condition characterized by the absence of the forebrain including the hypothalamus, offers a unique model to study pituitary development independently of hypothalamic influence.
Purpose of the Study:
- To investigate pituitary development in anencephalic fetuses, focusing on the differentiation and maintenance of adenohypophysial cells and hormone production in the absence of hypothalamic input.
- To examine the expression of key transcription factors (Pit-1, SF-1) and cellular markers (cytokeratins, S-100 protein) during pituitary development in anencephalic versus control fetuses.
Main Methods:
- Studied formalin-fixed paraffin-embedded pituitary tissue from 10 anencephalic fetuses and 10 age- and sex-matched controls.
- Utilized immunocytochemistry to detect adenohypophysial hormones, transcription factors (Pit-1, SF-1), cytokeratins, and S-100 protein.
Main Results:
- Anencephalic pituitaries lacked a posterior lobe but showed initial differentiation of hormone-producing cells and expression of transcription factors comparable to controls.
- Significant reductions in gonadotropes and corticotropes were observed in later gestation anencephalic pituitaries, indicating a dependence on hypothalamic factors for their maintenance.
- Increased S-100 protein immunoreactivity in abnormal cell populations was noted in anencephalic pituitaries after 32 weeks gestation.
Conclusions:
- Adenohypophysial cells can differentiate without hypothalamic influence, with key transcription factors expressed.
- Hypothalamic factors are essential for the maintenance of corticotropes and gonadotropes.
- Abnormal S-100 protein expression and the inconspicuous nature of fibrous bodies suggest altered pituitary cell function and structure in anencephaly.