Talk:Endocrine - Pituitary Development
Evaluation of the Hypothalamic-Pituitary-Adrenal Axis Function in Childhood and Adolescence
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2790806/?tool=pubmed
Hypophyseal triplication: case report and embryologic considerations
AJNR Am J Neuroradiol. 2009 Aug;30(7):1328-9. Epub 2009 Mar 19.
Manara R, Citton V, Rossetto M, Padoan A, D'Avella D.
Neuroradiologic Unit, University Hospital of Padua, Padua, Italy. renzo.manara@sanita.padova.it Abstract SUMMARY: Hypophyseal triplication is malformation that has not been described previously. We present a child with midline abnormalities who underwent epignathus excision at birth. Brain MR imaging revealed 2 paired lateral pituitary glands and an oval midline gland, each with an independent stalk, connected to a thickened third ventricle floor. Because malformations represent a failure in embryogenesis, this case may provide interesting clues on the normal development of the hypophysis.
PMID: 19299490
http://www.ajnr.org/cgi/reprint/30/7/1328
Theory comparison
- According to the classic theory,1,3,5 the hypophysis is believed to arise from 2 distinct structures, namely the diencephalic neuroectoderm (posterior lobe) and the oral ectoderm (anterior lobe). At approximately 42 days of gestation, a diverticulum originating from the stomodeum fuses with the downward extending diencephalic bud, both finally housed in the pituitary fossa.
- In contrast to the traditional view, Gilbert (1934) found that in mammalian species, both the anterior and posterior part of the gland originate from the ventral neural ridge.1 In this model, resumed by Morton in 19574 in a case report of pituitary duplication, the gland is supposed to arise entirely from neuroectodermal tis- sue without the primary involvement of the Rathke pouch.
Prenatal MR imaging of the normal pituitary stalk
AJNR Am J Neuroradiol. 2009 May;30(5):1014-6. Epub 2009 Feb 4.
Righini A, Parazzini C, Doneda C, Arrigoni F, Triulzi F.
Radiology and Neuroradiology Department, Children's Hospital V. Buzzi, ICP, Milan, Italy. neurorad@icp.mi.it Abstract BACKGROUND AND PURPOSE: Prenatal imaging data of the normal pituitary gland and in vivo information on the development of the pituitary region are lacking; however, we noticed that the pituitary stalk (PS) is visible occasionally in utero on MR images. Our main purpose was to establish the detection rate of the PS in healthy fetuses at various gestational ages (GAs) by using single-shot fast spin-echo T2-weighted images.
MATERIALS AND METHODS: We selected 73 fetal cases with normal findings on prenatal MR imaging and clinical postnatal follow-up. The GA ranged between 19 and 37 weeks. The 3 planes of MR imaging sections were 4 mm thick with 1.25 x 1.25 mm in-plane resolution. Two pediatric neuroradiologists evaluated in consensus whether the PS was present as a linear isointense structure connecting the hypothalamic region with the floor of sella turcica. In those cases in which the PS was visible on the sagittal section, the angle formed by the intersection of the PS and the sellar plane (SP) was measured (PS-SP angle).
RESULTS: The PS was detectable on at least 1 coronal or sagittal section from 19 to 25 weeks' GA in 30/42 fetuses (71.4% sensitivity); from 26 to 37 weeks' GA, the PS was detected in all 31 fetuses (100% sensitivity). The PS-SP angle decreased significantly with GA, being <90 degrees in all fetuses after gestational week 25.
CONCLUSIONS: At the current spatial resolution of clinical prenatal MR imaging, PS can be reliably detected after 25 weeks' GA, so in case of a missing visualization, a strong suspicion of pituitary region anomaly could be raised.
PMID: 19193754 http://www.ajnr.org/cgi/content/full/30/5/1014
Development and sexual dimorphism of the pituitary gland
Life Sci. 2007 Feb 13;80(10):940-4. Epub 2006 Nov 29.
MacMaster FP, Keshavan M, Mirza Y, Carrey N, Upadhyaya AR, El-Sheikh R, Buhagiar CJ, Taormina SP, Boyd C, Lynch M, Rose M, Ivey J, Moore GJ, Rosenberg DR.
Department of Psychiatry & Behavioral Neurosciences, Wayne State University, and Children's Hospital of Michigan, Detroit, MI 48201, USA. Abstract The pituitary gland plays a central role in sexual development and brain function. Therefore, we examined the effect of age and gender on pituitary volume in a large sample of healthy children and adults. Volumetric magnetic resonance imaging (MRI) was conducted in one hundred and fifty four (77 males and 77 females) healthy participants. Males were between the ages of 7 to 35 years (16.91+/-5.89 years) and females were 7 to 35 years of age (16.75+/-5.75 years). Subjects were divided into subgroups of age (7 to 9, 10 to 13, 14 to 17, 18 to 21, 22 and older) and sex (male/female). Pituitary gland volume differed between sexes when comparing the age groups (F=3.55, df=2, 143, p=0.03). Females demonstrated larger pituitary glands than males in the age 14 to 17 year old groups (p=0.04). Young (19 years and under) and old (20 years and older) females demonstrated a correlation between pituitary volume and age. Males did not show this relationship. These findings provide additional evidence for gender differences in the normative anatomy of the pituitary and may have relevance for the study of various childhood onset neuropsychiatric disorders in which pituitary dysfunction has been implicated.
PMID: 17174342 http://www.ncbi.nlm.nih.gov/pubmed/17174342
