View a partial list of
Robert Rosenfield’s publications through the National Library of Medicine's PubMed online database
Dr. Rosenfield conducts basic research projects on androgen secretion and action, as well as clinical research programs on reproductive physiology and growth, with special emphasis on the role of androgens and estrogens in females. Dr Rosenfield has held an NICHD grant Free Plasma Sex Hormone and Androgen Action for 28 years.
It began with the demonstration that plasma free testosterone is more closely related to the development of hirsutism in women than is the plasma total testosterone concentration, showed that hirsutism and acne were variably expressed manifestations of androgen excess, and culminated with the demonstration that peroxisome proliferator-activated receptors (PPARs), which are key regulators of the lipid metabolism necessary for fat cell (adipocyte) differentiation, are potent mediators of sebocyte differentiation. Some PPAR effects are amplified by androgen. Dr Dianne Deplewski started her research training in this project and continues to be active in it as a junior faculty member.
Dr Rosenfield was funded in by the NIH to study The Molecular Basis of Ovarian Testosterone Production and an expansion of these studies into hyperandrogenic women was funded by the NIH (Gonadotropin/insulin interactions in PCOS) as part of a Reproductive Center grant.
The molecular basis for testosterone formation from androstenedione within the human ovary was unknown until his laboratory recently demonstrated that this was accounted for by type 5 17ß-HSD (17ß-HSD5) expression. They have furthermore demonstrated that 17ß-HSD5 is localized to theca cells.
Currently under study are the factors regulating the expression of this enzyme and the relationship of polymorphisms in this enzyme to polycystic ovary syndrome (PCOS). This is a chronic hyperandrogenic disorder that typically appears during adolescence and is the most common cause of endocrine infertility in women. Dr Kenan Qin was involved in initiating this project as a pediatric endocrinology trainee and continues on in this project as a Research Associate. Another clinical aspect of this project is the characterization of insulin resistance in children at risk for having PCOS, such as those with premature pubarche or morbid obesity.
Dr. Elizabeth Littlejohn has returned on as a junior faculty member on a supplemental project.