| Pubertal attainment is regulated by many neuropeptides, which result in hypothalamic gonadotropin releasing hormone (GnRH) production and subsequent lutenizing hormone and follicle stimulating hormone secretion from the anterior pituitary gland. Bos indicus-influenced cattle are at a disadvantage in production systems because they achieve puberty at older ages than Bos taurus cattle. Objectives herein were to identify the neuropeptidome of hypothalamus and pituitary glands of pre- (PRE) and post- (POST) pubertal Brangus (3/8 Brahman x 5/8 Angus) heifers. Pubertal stage was determined via progesterone concentration; POST heifers had 88% greater circulating progesterone and heavier BW at slaughter than PRE heifers in the first study.;In the second study, we identified 240 total neuropeptides (i.e., ≤ 10 kDa in size) in both tissues. Pre-pubertal heifers expressed 28.46% more total peptides in hypothalamus than POST, where as in pituitary glands POST heifers expressed 31.05% more peptides than PRE females. Of the 240 neuropeptides, 93 were products of the pro-opiomelanocortin (POMC) precursor.;The third study quantified PEN-20, PCSK1N [61-89], CBLN1 [58-71], CART [28-36], PDNY [186-208], and WE-14 peptides in each heifer and tissue. PEN-20 and PCSKIN[61-89], peptides of the A4IFR2 gene, were higher in POST heifers. The CART [28-36] peptide, a product of CART gene and involved in POMC function was minimal in hypothalamus tissue, but overexpressed in POST pituitary glands. Peptides WE-14 and CBLN1 [58-71] were highly expressed in POST hypothalamus and pituitary, respectively. PDNY [186-208] was prevalent in PRE hypothalamus and POST pituitary samples. Neuropeptide Y and leptin were associated with 4 peptides, confirming the importance of adipocity and nutritional status in regulation of GnRH.;Cumulatively, we were able to use MS technology to establish the neuropeptidome of hypothalamus and pituitary glands in pre- and post-pubertal Brangus heifers. Additionally, detection of 240 neuropeptides established a hypothalamus and pituitary gland peptidome database for puberty in heifers. Quantitative analyses confirmed the importance of nutritional status and body fat stores in pubertal transition of heifers. |
