Embryonic Structures Commons^™

Molecular Mechanism Of Xy Gonadal Dysgenesis, Griendy Indig-Weingarten

The Science Journal of the Lander College of Arts and Sciences

One of the fundamentals of human sociology is the characterization of the people around us based on gender. We tend to think of gender as a strict binary system where the option is clear: boy or girl. Although society usually honors this dichotomy, biology allows more flexibility to the definition of male versus female. Estimates state that one in every 2000 births is one with a disorder of sex development (The Intersex Society of North America 2006). Some of the disorders are visually obvious while others are only discovered later on in life. Regardless of when the disease first becomes …

The Effects Of 17Α-Ethynylestradiol (Ee2) On Gonadal Development And Differentiation In The Estuarine Killifish, Fundulus Heteroclitus, Ibrahim Chehade

Theses and Dissertations (Comprehensive)

Endocrine disrupting substances (EDSs) comprise a wide variety of chemicals that perturb normal endocrine function including developmental and reproductive processes in vertebrates. The synthetic estrogen 17α-ethynylestradiol (EE₂) is a commonly-used model EDS because of its environmental relevance and its effects on the reproductive endocrine system. Early life-stage exposure of fish to estrogenic EDSs causes effects such as intersex (ovotestes in males) and feminization. This study aims to confirm the period of gonadal differentiation in the estuarine killifish or mummichog (Fundulus heteroclitus) and to determine the sensitivity of gonadal development to EE₂. Artificially-regressed mummichog were spawned, and …

The Role Of Sonic Hedgehog In The Hypothalamus, Solsire E. Zevallos

Publicly Accessible Penn Dissertations

ABSTRACT

THE REQUIREMENT OF SONIC HEDGEHOG IN THE HYPOTHALAMUS

Solsire E. Zevallos

Douglas J. Epstein

Sonic hedgehog (Shh) is a morphogen secreted during early development that is required for the formation of the ventral neural tube, including the ventral forebrain. The prechordal source of Shh underlying the forebrain is required early to bifurcate the cerebral hemispheres and eye vesicles as well as to specify a rostroventral forebrain region, the hypothalamus. We hypothesized that Shh expressed later in the hypothalamus may be required for other known functions of Shh, such as patterning within a region, cell proliferation, cell specification, and axon …