Terry M. Nett, PhD
Office: W133 ARBL Building, Foothills Campus
I teach an undergraduate course in human sexuality and participate in graduate courses on cellular endocrinology, radioimmunoassay techniques, and reproductive physiology.
Research Interests -- Reproductive Endocrinology
My research is directed at obtaining a better understanding of factors that regulate synthesis and secretion of hormones that control reproduction, particularly the gonadotropins follicle-stimulating hormone (FSH) and luteinizing hormone (LH). There are several different states in which blood levels of these hormones are insufficient to maintain reproductive processes, including seasonal and postpartum anestrus, during nutritional insufficiency and prior to puberty. Studies to elucidate mechanisms controlling synthesis and secretion of gonadotropins fall into three areas. First, during several reproductive states, secretion of LH increases while at the same time secretion of FSH decreases, or vice versa. The differential secretion of these gonadotropins occurs despite the fact that both are produced within the same cells of the anterior pituitary gland and that their synthesis and secretion are regulated by several of the same hormones. Studies to examine the subcellular mechanisms responsible for this differential regulation are underway. Second, gonadotropin-releasing hormone (GnRH) stimulates synthesis and secretion of the gonadotropins by interacting with membrane receptors in the anterior pituitary gland. The number of these receptors present dictates the sensitivity of the anterior pituitary gland to GnRH and, therefore, determines the quantity of LH and FSH that will be released in response to stimulation by GnRH. Regulation of the number of these receptors may well provide a novel method for controlling fertility in both males and females. Third, we are using highly potent analogs of GnRH in an attempt to deliver cytotoxic moieties specifically to gonadotrophin-producing cells in the anterior gland. Our goal is to develop a treatment that can permanently eliminate function of gonadotrophs without affecting other cells in the anterior pituitary gland. Such a treatment would have a variety of uses ranging from non-lethal control of wild animal populations to treatment of hormone-dependent cancers in humans.
For additional information on current projects, consult the page on Hypothalamic and Pituitary Function.
Turzillo AM, Juengel JL, Nett TM. 1995. Pulsatile GnRH increases concentrations of GnRH receptor mRNA and numbers of GnRH receptors during luteolysis in the ewe. Biol Reprod 53:418-423.
Vizcarra JA, Wettemann RP, Turzillo AM, Braden TD, Nett TM. 1997. Effect of GnRH pulse frequency on serum and pituitary concentrations of LH and FSH, GnRH receptors, and messenger RNA for gonadotropin subunits in cows. Endocrinology 138:594-601.
Turzillo AM, Nolan TE, Nett TM. 1998. Regulation of gonadotropin-releasing hormone (GnRH) receptor expression in sheep: Interaction of GnRH and estradiol. Endocrinology 139:4890-4894.
Turzillo AM, Clapper JA, Moss GE, Nett TM. 1998. Regulation of ovine GnRH receptor gene expression by progesterone and oestradiol. J Reprod Fertil 113:251-256.
Baratta M, West LA, Turzillo AM, Nett TM. 2001. Activin modulates differential effects of estradiol on synthesis and secretion of FSH in ovine pituitary cells. Biol Reprod 64:714-719.
Baker DL, Wild MA, Conner MM, Ravivarapu HB, Dunn RL, Nett TM. 2002. Effects of GnRH agonist (leuprolide) on reproduction and behaviour in female wapiti (Cervus elaphus nelsoni). Reproduction (Suppl) 60:155-167.
Nett TM, Turzillo AM, Baratta M, Rispoli LA. 2002. Pituitary effects of steroid hormones on secretion of follicle-stimulating hormone and luteinizing hormone. Dom Anim Endocrinol 23:33-42.
Yang W-H, Wieczoreck M, Allen MC, Nett TM. 2003. Cytotoxic activity of gonadotropin-releasing hormone (GnRH)-pokeweed antiviral protein conjugates in cell lines expressing GnRH receptors. Endocrinology 144:1456-1463.