title: Epidermal growth factor stimulates thyrotropin secretion in the rat.
abstract: The present work studied the effects of epidermal growth factor (EGF) on the release of thyrotropin (TSH) and prolactin (PRL) from perifused pituitary glands of 200-gram male Wistar rats. Each pituitary gland, cut into halves, was placed in a chamber of a perifusion system connected to a peristaltic pump which conveyed the perifusion medium (Medium 199, pH 7.3, Gibco, USA) from a reservoir to a chamber at a flow rate of 100 microliters/min. Each tightly closed chamber contained one pituitary gland and 600 microliters medium and it was placed in a water bath at 37 degrees C throughout the experiment. One milliliter samples of effluent were collected every 10 min for 60 min to obtain baseline values of TSH and PRL. Thereafter, TSH-releasing hormone (TRH) 10(-8) M or EGF (10(-11), 10(-10), 10(-9) or 10(-8) M) were added to individual chambers and the 10-min sampling of effluent continued for 60 min. EGF 10(-11) M elicited no TSH response, but 10(-10) and 10(-9) M doses induced significant increases in TSH secretion (p < 0.01) with a peak at 10 min after addition of EGF. In another experiment, EGF 10(-8) M or TRH 10(-8) M significantly elevated TSH secretion (p < 0.01). However, TRH, but not EGF, stimulated PRL secretion (p < 0.01). In the in vivo studies, the intravenous administration of EGF 10(-5) M or TRH 10(-5) M both induced significant elevation of TSH release at 10 min after the injection (p < 0.02 for EGF and p < 0.01 for TRH).(ABSTRACT TRUNCATED AT 250 WORDS)
authors: CONICET, Hospital de Clinicas, Instituto de Neurobiologia, Buenos Aires, Argentina.
authors: L R
authors: LR
authors: Altschuler
authors: M N
authors: MN
authors: Parisi
authors: L F
authors: LF
authors: Cageao
authors: S R
authors: SR
authors: Chiocchio
authors: J A
authors: JA
authors: Fernandez-Pol
authors: A A
authors: AA
authors: Zaninovich
mesh_terms: D000818:Animals; D004815:Epidermal Growth Factor / Q000502:physiology*; D066298:In Vitro Techniques; D008297:Male; D010902:Pituitary Gland / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013972:Thyrotropin / Q000378:metabolism*; D013973:Thyrotropin-Releasing Hormone / Q000502:physiology; D013974:Thyroxine / Q000502:physiology
chemical_list: D013973:Thyrotropin-Releasing Hormone; D004815:Epidermal Growth Factor; D013972:Thyrotropin; D013974:Thyroxine