Barb C R, Kraeling R R, Barrett J B, Rampacek G B, Campbell R M, Mowles T F
Russell Research Center, USDA, ARS, Athens, Georgia 30613.
Proc Soc Exp Biol Med. 1991 Oct;198(1):636-42. doi: 10.3181/00379727-198-43301.
Two experiments were conducted to determine the effect of free fatty acids (FFA) and glucose treatment on growth hormone (GH) and luteinizing hormone secretion in the pig. In Experiment (Exp) 1, 15 prepuberal gilts received an intravenous infusion of FFA (n = 5; 3 ml of 10% Liposyn II/kg), glucose (n = 5; 1 g/kg), or saline (n = 5; 3 ml of 0.9%/kg). Jugular blood samples were collected every 15 min for 2 hr before and 3 hr after intravenous infusion of saline, FFA, and glucose. Synthetic [Ala15]-h growth hormone-releasing factor-(1-29)NH2 (1 microgram/kg) and gonadotropin-releasing hormone (0.2 micrograms/kg) were administered 30 min after infusion (Time 0 = infusion). In Exp 2, eight prepuberal gilts received either FFA (n = 4) or saline (n = 4) as described in Exp 1, except that treatments were given every hour ove a 10-hr period. Blood samples were collected every 15 min from 1 hr before to 10 hr after the start of FFA or saline infusion. In Exp 1, the peak GH response to growth hormone-releasing factor was delayed by 45 min (P less than 0.01) by glucose treatment and suppressed (P less than 0.01) by FFA treatment. The luteinizing hormone response to gonadotroph-releasing hormone was suppressed (P less than 0.03) by glucose and enhanced (P less than 0.03) by FFA. In Exp 2, the number of GH pulses was increased (P less than 0.05) by FFA infusion and GH concentrations were positively correlated (r = 0.58, P less than 0.0003) with FFA concentrations, while luteinizing hormone pulse amplitude was greater (P less than 0.01) in FFA gilts than in saline gilts. These results indicate that FFA are more effective modulators of GH secretion than acute hyperglycemia, while metabolic status can alter pituitary responsiveness to gonadotropin-releasing hormone.
进行了两项实验，以确定游离脂肪酸（FFA）和葡萄糖处理对猪生长激素（GH）和促黄体生成素分泌的影响。在实验（Exp）1中，15头青春期前的小母猪接受静脉输注FFA（n = 5；3 ml 10% Liposyn II/kg）、葡萄糖（n = 5；1 g/kg）或生理盐水（n = 5；3 ml 0.9%/kg）。在静脉输注生理盐水、FFA和葡萄糖之前2小时和之后3小时，每15分钟采集一次颈静脉血样。在输注后30分钟（时间0 = 输注）给予合成的[Ala15]-h生长激素释放因子-(1 - 29)NH2（1微克/千克）和促性腺激素释放激素（0.2微克/千克）。在实验2中，8头青春期前的小母猪接受如实验1中所述的FFA（n = 4）或生理盐水（n = 4），不同之处在于处理在10小时内每小时给予一次。从FFA或生理盐水输注开始前1小时到输注后10小时，每15分钟采集一次血样。在实验1中，葡萄糖处理使生长激素对生长激素释放因子的峰值反应延迟45分钟（P < 0.01），FFA处理使其受到抑制（P < 0.01）。葡萄糖使促黄体生成素对促性腺激素释放激素的反应受到抑制（P < 0.03），FFA使其增强（P < 0.03）。在实验2中，FFA输注使GH脉冲数量增加（P < 0.05），GH浓度与FFA浓度呈正相关（r = 0.58，P < 0.0003），而FFA处理的小母猪促黄体生成素脉冲幅度比生理盐水处理的小母猪更大（P < 0.01）。这些结果表明，FFA对GH分泌的调节作用比急性高血糖更有效，而代谢状态可改变垂体对促性腺激素释放激素的反应性。
