Somatotroph, lactotroph and thyrotroph function in three-week-old gilts reared in a hot or cool environment

Abstract The influence of the thermal environment on the ability of the pituitary gland to secrete growth hormone (GH), prolactin (PRL), and thyroid-stimulating hormone (TSH) was examined in gilts reared under hot (H: 27–32°C, 50–90% RH, n = 6) or cool (C: 20°C, 50% RH, n = 6) conditions. Piglets were sacrificed at 3 wks of age. Pituitary cells from each animal were cultured and exposed to vehicle (culture medium); .1, 1, and 10 nM thyrotropin-releasing hormone (TRH); .1, 1, and 10 nM growth hormone-releasing hormone (GHRH); 59 mM KCl; 2 mM 8-Br-cAMP; and 100 nM phorbol myristate acetate. Rearing in the H, compared to the C, environment increased plasma PRL concentrations (p