The pituitary adrenocorticotropes originate from neural ridge tissue in Xenopus laevis

Development ◽  
1986 ◽  
Vol 95 (1) ◽  
pp. 1-14
Author(s):  
Gerald W. Eagleson ◽  
Bruce G. Jenks ◽  
A. P. van Overbeeke
Keyword(s):  
Xenopus Laevis ◽  
Anterior Pituitary ◽  
Preoptic Region ◽  
Anterior Portion ◽  
Pituitary Development ◽  
Immunocytochemical Techniques ◽  
Nucleus Infundibularis ◽  
Tube Closure

A series of grafting experiments was conducted to determine pituitary origins prior to brain tube closure in Xenopus laevis. Extirpation experiments indicated that the ventral neural ridge (VNR) tissue of stage-18+ embryos was essential for pituitary development. Bolton–Hunter reagent was used to label stage-18+ VNR tissue with 125I, and this tissue was then returned to the donor and its subsequent ontogenesis followed. Labelled tissue was ultimately found in the ventral hypothalamus, the ventral retina, and the anterior pituitary. Using immunocytochemical techniques with antisera to adrenocorticotropin (ACTH), it was found that some of the VNR-derived cells were corticotropes. A region of the nucleus infundibularis which was radioactive labelled also gave ACTH-positive immunoreaction. This might indicate that some ACTH containing neurones of the hypothalamus are VNR in origin. We suggest that stage-18+ VNR is the site of attachment of brain and anterior pituitary ectoderm. Part of this adherence point is eventually incorporated into the anterior pituitary and will form corticotropes. It is concluded that the ventral retina, the preoptic region of the hypothalamus, some hypothalamic ACTH-immunoreactive cells, and the most anterior portion of the adenohypophysis are all ventral neural ridge in origin.

Lhx4 and Prop1 are required for cell survival and expansion of the pituitary primordia

Development ◽  
2002 ◽  
Vol 129 (18) ◽  
pp. 4229-4239 ◽  
Author(s):  
Lori T. Raetzman ◽  
Robert Ward ◽  
Sally A. Camper
Keyword(s):  
Cell Survival ◽  
Anterior Pituitary ◽  
Molecular Genetic ◽  
Cell Types ◽  
Hormone Deficiency ◽  
Pituitary Hormone ◽  
Pituitary Cells ◽  
Temporal Shift ◽  
Pituitary Development ◽  
Show Evidence

Deficiencies in the homeobox transcription factors LHX4 and PROP1 cause pituitary hormone deficiency in both humans and mice. Lhx4 and Prop1 mutants exhibit severe anterior pituitary hypoplasia resulting from limited differentiation and expansion of most specialized cell types. Little is known about the mechanism through which these genes promote pituitary development. In this study we determined that the hypoplasia in Lhx4 mutants results from increased cell death and that the reduced differentiation is attributable to a temporal shift in Lhx3 activation. In contrast, Prop1 mutants exhibit normal cell proliferation and cell survival but show evidence of defective dorsal-ventral patterning. Molecular genetic analyses reveal that Lhx4 and Prop1 have overlapping functions in early pituitary development. Double mutants exhibit delayed corticotrope specification and complete failure of all other anterior pituitary cell types to differentiate. Thus, Lhx4 and Prop1 have critical, but mechanistically different roles in specification and expansion of specialized anterior pituitary cells.

Transcriptional control during mammalian anterior pituitary development

Gene ◽  
2003 ◽  
Vol 319 ◽  
pp. 1-19 ◽  
Author(s):  
Jesse J Savage ◽  
Benjamin C Yaden ◽  
Parinda Kiratipranon ◽  
Simon J Rhodes
Keyword(s):  
Anterior Pituitary ◽  
Transcriptional Control ◽  
Pituitary Development

scholarly journals The protein activator of protein kinase R, PACT/RAX, negatively regulates protein kinase R during mouse anterior pituitary development

FEBS Journal ◽  
2015 ◽  
Vol 282 (24) ◽  
pp. 4766-4781 ◽  
Author(s):  
Benjamin K. Dickerman ◽  
Christine L. White ◽  
Patricia M. Kessler ◽  
Anthony J. Sadler ◽  
Bryan R. G. Williams ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Anterior Pituitary ◽  
Protein Kinase R ◽  
Pituitary Development ◽  
Protein Activator

scholarly journals Deletion of OTX2 in neural ectoderm delays anterior pituitary development

2014 ◽  
Vol 24 (4) ◽  
pp. 939-953 ◽  
Author(s):  
Amanda H. Mortensen ◽  
Vanessa Schade ◽  
Thomas Lamonerie ◽  
Sally A. Camper
Keyword(s):  
Anterior Pituitary ◽  
Pituitary Development ◽  
Neural Ectoderm

INHIBITION OF OVULATION IN THE RAT BY INTRAHYPOTHALAMIC IMPLANTS OF AN ANTIOESTROGEN

1973 ◽  
Vol 56 (3) ◽  
pp. 585-590 ◽  
Author(s):  
ROLAND BILLARD ◽  
P. G. McDONALD
Keyword(s):  
Cocoa Butter ◽  
Median Eminence ◽  
Positive Feedback ◽  
Anterior Pituitary ◽  
Critical Period ◽  
Preoptic Area ◽  
Preoptic Region

SUMMARY In order to determine the sites at which oestradiol exerts its positive feed back effect, double-walled cannulae containing the antioestrogen ICI 46,474 were implanted into the preoptic area, median eminence or anterior pituitary. Implants were made at different stages of the cycle and left in place for between 4 and 96 h. Implants in the preoptic area for 24, 48 or 96 h did not significantly inhibit ovulation. Implants placed in the median eminence for 24 h before the critical period significantly inhibited ovulation when compared with controls (P < 0·02). Implantation of antioestrogen in the anterior pituitary for a similar 24-h period was ineffective in blocking ovulation. However, when mixed with cocoa butter and implanted in the anterior pituitary the antioestrogen significantly inhibited ovulation (P < 0·02). The results show that by preventing the action of oestradiol on either the pituitary or the median eminence, ovulation may be inhibited. Ovulation was not affected by implants in the preoptic region which suggests that this area is not involved in the positive feedback action of oestradiol.

scholarly journals Pro239Ser: A Novel Recessive Mutation of the Pit-1 Gene in Seven Middle Eastern Children with Growth Hormone, Prolactin, and Thyrotropin Deficiency1

1998 ◽  
Vol 83 (6) ◽  
pp. 2079-2083 ◽  
Author(s):  
Flavia Pernasetti ◽  
Robert D. G. Milner ◽  
Abdullah A. Z. Al Ashwal ◽  
Francis de Zegher ◽  
Viviana M. Chavez ◽  
...  
Keyword(s):  
Gene Expression ◽  
Growth Hormone ◽  
Anterior Pituitary ◽  
Middle Eastern ◽  
Recessive Mutation ◽  
Specific Gene ◽  
Pituitary Development ◽  
Domain Protein ◽  
Α Helix ◽  
Tsh Deficiency

Pit-1, a member of the POU-homeo domain protein family, is one of the transcription factors responsible for anterior pituitary development and pituitary-specific gene expression. Here, we describe seven children with GH, PRL, and TSH deficiency from three, reportedly unrelated, Middle Eastern families, harboring a newly recognized Pro-&gt;Ser recessive mutation in codon 239 of the Pit-1 gene. The mutated residue is located at the beginning of the second α-helix of the POU-homeodomain and is strictly conserved among all POU proteins. The Pro239Ser mutant binds DNA normally but is unable to stimulate transcription.

scholarly journals Changes in Gene Expression during Pituitary Morphogenesis and Organogenesis in the Chick Embryo

Endocrinology ◽  
2011 ◽  
Vol 152 (3) ◽  
pp. 989-1000 ◽  
Author(s):  
Monika Proszkowiec-Weglarz ◽  
Stacy E. Higgins ◽  
Tom E. Porter
Keyword(s):  
Gene Expression ◽  
Mrna Expression ◽  
Anterior Pituitary ◽  
Molecular Mechanisms ◽  
Expression Profiles ◽  
Expression Patterns ◽  
Mrna Levels ◽  
Pituitary Development ◽  
Excellent Model ◽  
Functional Development

The anterior pituitary gland plays an important role in the regulation of many physiological processes. Formation of Rathke's pouch (RP), the precursor of the anterior pituitary, involves evagination of the oral ectoderm in a multi-step process regulated by cell interactions, signaling pathways, and transcription factors. Chickens are an excellent model to study development because of the availability of large sample sizes, accurate timing of development, and embryo accessibility. The aim of this study was to quantify mRNA expression patterns in the developing chicken anterior pituitary to evaluate the chicken embryo as a model for mammalian pituitary development. The expression profiles of 16 genes differentially expressed in RP and neuroectoderm were determined in this study. Among these, Pitx1, Pitx2, and Hesx1 mRNA levels were high on embryonic days (e) 2.5 to e3 in RP and decreased during development. Expression of Pit1 and Tbx19 mRNA in RP reached the highest levels by e7 and e6.5, respectively. Levels of glycoprotein subunit α mRNA increased beginning at e4. FGF8 mRNA showed the highest expression at e3 to e3.5 in neuroectoderm. BMP2 showed slight decreases in mRNA expression in both tissues during development, while Isl1 and Noggin mRNA expression increased in later development. Taken together, we present the first quantitative transcriptional profile of pituitary organogenesis. Our results will help further understanding of the functional development of this gland. Moreover, because of the high similarity in gene expression patterns observed between chicken and mouse, chickens could serve as an excellent model to study genetic and molecular mechanisms underlying pituitary development.

scholarly journals The Biological Basis of Sexual Behaviour in Amphibia

1936 ◽  
Vol 13 (1) ◽  
pp. 48-56
Author(s):  
H. A. SHAPIRO
Keyword(s):  
Xenopus Laevis ◽  
Anterior Pituitary ◽  
Anterior Lobe ◽  
Complete Disappearance ◽  
Fresh Tissue ◽  
Negative Results ◽  
Stage 4 ◽  
Pregnancy Urine ◽  
Breeding Seasons

1. The complete disappearance of all sexual activity in Xenopus laevis, male or female, is observed under laboratory conditions. 2. A technique is described whereby the mating reflex (coupling) can be established in the laboratory during the pond breeding season as well as midway between breeding seasons, by means of injections of human pregnancy urine extracts, or by acid extracts of the anterior lobe of the pituitary gland of sheep and goats. 3. The mating reflex has been induced in 101 different pairs of toads with pregnancy urine extracts and in 39 different pairs of toads with anterior pituitary extracts. 4. The reflex induced by anterior pituitary extracts in no way differs from that produced by pregnancy urine extracts. 5. The possibility that the extract acts through the intermediation of the gonads is considered. 6. The mating reflex is described, and attention is drawn to the passive role of the female, while the male is stimulated to activity. 7. It is suggested that a stimulus from the female reflexly activates the male to clasping activity. 8. Fertilised ova from coupling pairs have been reared successfully to an advanced tadpole stage (4-5 months). Tadpoles can be reared also midway between breeding seasons. 9. The injected extract, acting possibly through the intermediation of the gonads, may be suggested to inhibit the clasping reflex inhibitory centre in the brain described by Steinach and others. 10. The mating reflex appears to be independent of the pituitary mechanism associated with chromatic response in Xenopus laevis. 11. The larger doses (500 mg. fresh tissue) of anterior pituitary extract required to produce in summer a response of the same magnitude as that produced by smaller doses (192 mg. fresh tissue) in winter cannot be attributed to a diminished sensitivity of the ovaries. 12. Control extracts of male urine and of sheep and goat brains repeatedly gave negative results.

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