Role of GH in regulating nocturnal rates of lipolysis and plasma mevalonate levels in normal and diabetic humans

PJ Boyle, A Avogaro, L Smith, DM Bier… - American Journal …, 1992 - journals.physiology.org
PJ Boyle, A Avogaro, L Smith, DM Bier, AS Pappu, DR Illingworth, PE Cryer
American Journal of Physiology-Endocrinology and Metabolism, 1992journals.physiology.org
To define the role that nocturnal increments in growth hormone (GH) play in maintaining
lipolysis, glycerol turnover was measured in six patients with GH deficiency and six normal
subjects during sleep. Glycerol production initially decreased in both groups but then
increased to 1.44+/-0.20 mumol. kg-1. min-1 by 0800 h in normal subjects, whereas GH
deficiency was associated with a continuous fall to 0.77+/-0.10 mumol. kg-1. min-1, P less
than 0.02. Nonesterified fatty acid levels paralleled these changes. Six GH-deficient patients …
To define the role that nocturnal increments in growth hormone (GH) play in maintaining lipolysis, glycerol turnover was measured in six patients with GH deficiency and six normal subjects during sleep. Glycerol production initially decreased in both groups but then increased to 1.44 +/- 0.20 mumol.kg-1.min-1 by 0800 h in normal subjects, whereas GH deficiency was associated with a continuous fall to 0.77 +/- 0.10 mumol.kg-1.min-1, P less than 0.02. Nonesterified fatty acid levels paralleled these changes. Six GH-deficient patients received basal GH replacement including a pulse during sleep, which resulted in normal fasting fatty acid levels (P less than 0.05, replaced vs. chronic deficiency). To assess a possible link between the normal nocturnal increase in plasma mevalonate (the product of the rate-limiting step in cholesterol synthesis) and sleep-associated GH release, 11 GH-deficient patients and 11 normal subjects were studied. Peak nocturnal and fasting mevalonate concentrations were not correlated with GH level. We conclude that nocturnal growth hormone secretion is essential for maintaining lipolysis but that it is not related to normal increments in mevalonate and, by inference, to cholesterol synthesis during sleep
American Physiological Society