Dr. Hayes’ area of expertise is human reproductive physiology, a topic on which she has published widely.

Her research interests include the neuroendocrine regulation of fertility in men, specifically the interplay between gonadotropin-releasing hormone, sex steroids, and non-steroidal factors in the regulation of FSH secretion. These studies have disclosed a previously unrecognized hypothalamic site of action of estradiol in men and provide evidence that estradiol rather than testosterone is the major sex steroid regulator of FSH secretion in men. In addition, she has demonstrated that inhibin B is more important than sex steroids in the control of FSH secretion in men.

Her present research explores the relationship between testosterone and insulin resistance in men. To date, her studies have shown that insulin resistance in men is associated with a decrease in testicular Leydig cell secretion of testosterone. She is currently examining the impact of short-term medical castration on insulin sensitivity in normal healthy men as well as the impact of testosterone supplementation in men with the metabolic syndrome. Given the significant cardiovascular morbidity and mortality associated with obesity and type 2 diabetes, a clearer understanding of the interplay between testosterone and insulin resistance has important public health implications and may facilitate the development of new therapeutic strategies for these very common metabolic disorders.

Her clinical practice covers the spectrum of reproductive endocrinology including polycystic ovary syndrome, infertility, and male and female hormone replacement therapy for hypogonadism. She coordinates the NIH-sponsored program of long-term pulsatile GnRH administration for men with congenital GnRH deficiency, a therapy that is currently limited to a few academic centers in the United States. In addition, she has expertise in ovulation induction with clomiphene, gonadotropins and pulsatile GnRH for women with idiopathic or anovulatory infertility.

SELECTED PUBLICATIONS

• Hayes FJ, Taylor AE, Martin KM, Hall JE. Use of a GnRH antagonist as a physiologic probe in polycystic ovary syndrome: assessment of neuroendocrine and androgen dynamics. J Clin Endocrinol Metab 1998; 83:2343-2349

Seminara SB*, Hayes FJ*, Crowley Jr, WF. GnRH deficiency in the human (Idiopathic hypogonadotropic hypogonadism & Kallmann’s syndrome): Pathophysiologic and genetic considerations. Endo Rev 1998;19:521-539

• Hayes FJ, Seminara SB, DeCruz S, Boepple PA, Crowley WF Jr. Aromatase inhibition in the human male reveals a hypothalamic site of estrogen feedback. J Clin Endocrinol Metab. 2000; 85:3027-3035.

• Hayes FJ. Testosterone – Fountain of Youth or Drug of Abuse? J Clin Endocrinol Metab. 2000: 85:3020-3023

• Hayes FJ, DeCruz, Seminara SB, Boepple PA, Crowley WF Jr. Differential regulation of gonadotropin secretion by testosterone in the human male: absence of a negative feedback effect of testosterone on FSH secretion. J Clin Endocrinol Metab. 2001; 86:53-58

• Hayes FJ. Androgen replacement in the male: recent studies. In: Hall JE (ed) Current Opinion in Endocrinology and Diabetes. Philadelphia: Lippincott Williams & Wilkins; 2001;8:301-306•

Hayes FJ, Pitteloud N, DeCruz S, Crowley WF Jr, Boepple PA. Importance of Inhibin B in the Regulation of FSH secretion in the human male. J Clin Endocrinol Metab. 2001;86: 5541-5546

• Pitteloud N, Hayes FJ, Boepple PA, DeCruz S, Seminara SB, MacLaughlin DT, Crowley WF, Jr. The role of prior pubertal development, biochemical markers of testicular maturation, and genetics in elucidating the phenotypic heterogeneity of idiopathic hypogonadotropic hypogonadism. J Clin Endocrinol Metab. 2002;87:152-160

• Pitteloud N, Villegas J, Dwyer AA, Crowley WF, Jr, McPhaul MJ, Hayes FJ. Acute stress masking the biochemical phenotype of partial androgen insensitivity syndrome in a patient with a novel mutation in the androgen receptor. J Clin Endocrinol Metab. 2004; 89:1053-1058