title: Pre- and postpubertal LH and estradiol pattern in gilts subjected to intermittent inescapable electroshock.
abstract: The effect of intermittent electroshock on LH and estradiol secretory pattern and on reaching puberty was studied in 24 prepubertal gilts. Twelve gilts 115-168 days of age received unpredictable and inescapable electroshocks 0-5 times daily between 8 am and 4 pm and 12 gilts served as controls. At an age of 168 +/- 0.7 days all gilts were moved, regrouped and exposed to a boar for 30 min. Observations for signs of oestrus were carried out twice daily. Indwelling jugular catheters were inserted into 8 gilts on each treatment after the initial boar contact. Blood samples were collected to determine LH profiles for 4 h every 15 min on day 2 and day 4 after the initial boar contact. The remaining 4 gilts on each treatment were catheterized one day prior to the initial boar contact and blood was collected to determine LH profiles the day before initial boar contact and day 1 and day 2 after initial boar contact for 6 h every 15 min. In addition, blood samples were collected and analyzed for LH and estradiol from all gilts daily at 8 am, 12 am and 4 pm for the first 3 days following the initial boar contact and thereafter every 4 h until the end of oestrus (diurnal samples). Samples taken daily at noon the first 5 days following initial boar contact were analyzed for cortisol. The electroshock treatment significantly increased the age at puberty (p = 0.04) and tended to decrease the mean LH concentration prior to the preovulatory LH surge (p = 0.08) and the maximal concentration of LH during the preovulatory LH surge (p = 0.07). The apparent down regulation of the plasma concentration of LH was not associated with increased activity in the hypothalamus-pituitary-adrenal axis in that the basal concentration of cortisol was not affected by treatment. This indicates that other physiological mechanisms are involved in stress-induced suppression of LH.
authors.affiliation: National Institute of Animal Science, Dept. of Research in Pigs and Horses, Tjele, Denmark. LJP@KVL.DK
authors.forename: L J
authors.initials: LJ
authors.lastname: Pedersen
authors.forename: K H
authors.initials: KH
authors.lastname: Jensen
authors.forename: E
authors.initials: E
authors.lastname: Jørgensen
mesh_terms: D000818:Animals; D004597:Electroshock / Q000009:adverse effects / Q000662:veterinary*; D004958:Estradiol / Q000097:blood*; D005260:Female; D007986:Luteinizing Hormone / Q000097:blood*; D012741:Sexual Maturation / Q000502:physiology*; D013552:Swine / Q000097:blood*; D013997:Time Factors
chemical_list: D004958:Estradiol; D007986:Luteinizing Hormone