The long term goal of this project is to determine the structure and physiological significance of pineal peptides which affect reproduction. The major focus of the proposed project is to determine the distribution and mechanism of action of a novel antigonadotropic decapeptide (AGD) discovered during the last granting period. Acute i.v. injection of either the natural or synthetic AGD reduced serum levels of LH and PRL in rodents. In other experiments pulsatile LH secretion was inhibited by its microinfusion into the third ventricle. Preliminary results suggest that the AGD stimulates the release of dopamine from rat hypothalamic median eminence in vitro, providing a potential site and mechanism for its antigonadotropic action. Polyclonal antisera were raised against the AGD in rabbits and the antibodies purified by affinity chromatography. Also, the AGD was iodinated with (125)I and a radioimmunoassay (RIA) developed for its measurement. Proposed experiments will examine the distribution of endogenous AGD in rat tissues and body fluids by RIA. Immunoreactive AGD will be localized in the central nervous system by immunohistochemistry. Additionally, the distribution of radiolabeled AGD will be examined by autoradiography after i.v. injection. Other experiments will attempt to localize the site of action by acute stereotaxic microinjection of the AGD into a variety of selected sites in the central nervous system. Studies aimed at a determination of the mechanism of action will include an examination of the effects of AGD on catecholamine turnover rates in the preoptic area, hypothalamus and brain stem. The mechanism of the stimulatory effect of the AGD on dopamine release will be also be studied on rat median eminence perifused in vitro. Other experiments will examine its effects on pubertal development and ovulation. Finally, studies will continue on the purification, isolation and structure determination of a bovine pineal GnRH-like peptide.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
5R01HD019521-08
Application #
3316817
Study Section
Reproductive Biology Study Section (REB)
Project Start
1986-08-01
Project End
1996-08-31
Budget Start
1993-09-01
Budget End
1994-08-31
Support Year
8
Fiscal Year
1993
Total Cost
Indirect Cost
Name
University of Arizona
Department
Type
Schools of Medicine
DUNS #
City
Tucson
State
AZ
Country
United States
Zip Code
85721
Benson, B; Machen, N; Dunn, A M et al. (1996) Chronic lateral ventricle infusion of a pineal gland-derived decapeptide alters pulsatile secretion of LH in rats. Life Sci 58:1083-90
Benson, B; Machen, N (1994) Infusion of a pineal gland-derived antigonadotropic decapeptide into the lateral ventricle depresses prolactin levels in male rats. Life Sci 55:263-8
Zhang, Z; Benson, B; Logan, J L (1992) Dietary fish oil delays puberty in female rats. Biol Reprod 47:998-1003
Benson, B; Ebels, I; Hruby, V J (1990) Isolation and structure elucidation of bovine pineal arginine vasopressin: arginine vasotocin not identified. Int J Pept Protein Res 36:109-21
Benson, B; Reynolds, W D; Burns, D M et al. (1989) Diurnal variation in norepinephrine-stimulated release of pineal serotonin in vitro. J Neural Transm Gen Sect 78:89-101