Caffeine stimulates in vitro pituitary LH secretion in lipopolysaccharide-treated ewes.
The study was designed to determine the effects of caffeine on luteinizing hormone (LH) secretion and gene expression of caffeine-associated receptors in anterior pituitary (AP) explants obtained from saline- and lipopolysaccharide (LPS)-treated ewes. Animals had been treated with LPS or saline daily for seven days. Three hours after the last injection of LPS/saline, the AP were collected and divided into four explants. The explants were incubated with: 1/medium-199 (control explants), 2/gonadotropin-releasing hormone (GnRH; 100 pmol/mL; a positive control), 3/caffeine (10 mmol/L), or 4/GnRH+caffeine. Caffeine stimulated (p<0.05) LH release by explants from both saline (19.7 vs. control 12.6 ng/mg) and LPS (28.3 vs. control 13.9 ng/mg) treated animals. The effect of caffeine on LH secretion was stronger in the LPS-treated group than in saline-treated group, and the observed LH release was similar to that induced by GnRH alone (27.2 ng/mg). Caffeine increased (p<0.05) LHβ gene expression only in explants from LPS-treated animals. In conclusion, the results of the present study demonstrated a stimulatory in vitro effect of caffeine on LH secretion by ovine pituitary explants. The potency of the caffeine-induced LH secretion was affected by in vivo treatment of the animals with endotoxin.
Polish Academy of Sciences, The Kielanowski Institute of Animal Physiology and Nutrition, 05-110 Jabłonna, Poland. Electronic address: andrewherman@wp.pl.
Andrzej Przemysław
AP
Herman
The Academy of Cosmetics and Health Care, 13 Podwale Street, 00-252 Warsaw, Poland.
Anna
A
Herman
Polish Academy of Sciences, Institute of Animal Reproduction and Food Research, 10 Tuwima Street, 10-747 Olsztyn, Poland.
Janina
J
Skipor
Polish Academy of Sciences, The Kielanowski Institute of Animal Physiology and Nutrition, 05-110 Jabłonna, Poland.
Agata
A
Krawczyńska
Polish Academy of Sciences, The Kielanowski Institute of Animal Physiology and Nutrition, 05-110 Jabłonna, Poland.
Joanna
J
Bochenek
Polish Academy of Sciences, The Kielanowski Institute of Animal Physiology and Nutrition, 05-110 Jabłonna, Poland.
Dorota
D
Tomaszewska-Zaremba
D000818:Animals; D002110:Caffeine / Q000737:chemistry / Q000494:pharmacology*; D005260:Female; D008070:Lipopolysaccharides / Q000633:toxicity*; D007986:Luteinizing Hormone / Q000378:metabolism*; D010902:Pituitary Gland / Q000187:drug effects* / Q000378:metabolism; D012756:Sheep / Q000502:physiology*
D008070:Lipopolysaccharides; D002110:Caffeine; D007986:Luteinizing Hormone
Adenosine receptors; Anterior pituitary; Caffeine; Luteinizing hormone; Ryanodine receptors