title: Glucose and free fatty acid modulation of growth hormone and luteinizing hormone secretion by cultured porcine pituitary cells.
abstract: The influence of glucose and free fatty acids (FFA) on LH and GH secretion from porcine pituitary cells was examined in culture. Cells were challenged with 10(-9), 10(-8), or 10(-7) M GnRH; 10(-9), 10(-8), or 10(-7) M [Ala15]-h growth hormone-releasing factor-(1-29)NH2 (GRF); 10(-3) or 10(-5) M forskolin; glucose (100, 300, or 600 mg/dL); and oleic or linoleic acid (10(-11) to 10(-5) M) individually or in combinations of glucose, oleic, and linoleic acid with GnRH, GRF, or forskolin. Relative to control (medium alone), GnRH increased (P < .003) LH secretion. Glucose at 100 mg/dL enhanced (P < .05) basal LH release, whereas the 600-mg/dL dose suppressed (P < .05) LH response to GnRH. Except for 10(-7) M, all doses of linoleic acid increased (P < .05) basal LH release, whereas only 10(-5) M linoleic acid suppressed (P < .02) LH response to GnRH. All doses of oleic acid enhanced (P < .05) basal LH release and suppressed (P < .03) the LH response to GnRH. In contrast, neither FFA suppressed the forskolin-induced LH secretion compared to forskolin alone. Growth hormone-releasing factor stimulated (P < .02) GH release in a dose-dependent manner. Glucose did not alter basal GH release but suppressed (P < .01) GRF-induced GH release. Only 300 mg/dL of glucose suppressed (P < .05) forskolin-induced GH release.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: ARS, USDA, Athens, GA 30604-5677, USA.
authors.forename: C R
authors.initials: CR
authors.lastname: Barb
authors.forename: R R
authors.initials: RR
authors.lastname: Kraeling
authors.forename: G B
authors.initials: GB
authors.lastname: Rampacek
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005230:Fatty Acids, Nonesterified / Q000494:pharmacology*; D005260:Female; D005947:Glucose / Q000494:pharmacology*; D013006:Growth Hormone / Q000378:metabolism*; D013007:Growth Hormone-Releasing Hormone / Q000494:pharmacology; D007986:Luteinizing Hormone / Q000378:metabolism*; D010902:Pituitary Gland / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D013552:Swine / Q000378:metabolism*
chemical_list: D005230:Fatty Acids, Nonesterified; D005576:Colforsin; D007986:Luteinizing Hormone; D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone; D005947:Glucose