title: Growth hormone therapy initiated before starvation ameliorates the catabolic state and enhances the protein-sparing effect of total parenteral nutrition.
abstract: The effect of 7 days of subcutaneously administered bovine growth hormone (bGH) (0.2 mg kg-1 day-1; n = 4) or an equivalent volume of 0.15 mol l-1 saline (n = 3) on protein metabolism was assessed in lambs. The catabolic response to 48 h of starvation and subsequent hypocaloric total parenteral nutrition (TPN) was measured using primed constant intravenous infusions of [15N]urea and [14C]leucine. Following 48 h of starvation and 7 h of TPN, bGH-treated animals had a significantly decreased rate of net protein catabolism compared with controls (mean(s.e.m.) 2.4(0.2) versus 3.2(0.3) g kg-1 day-1, P < 0.01). The mean(s.e.m.) rate of whole-body protein catabolism was also significantly decreased in bGH-treated animals at 10.9(0.3) g kg-1 day-1 compared with 12.9(0.7) g kg-1 day-1 in saline-treated controls (P < 0.05). In addition, the rates of net and whole-body protein catabolism decreased significantly (P < 0.05) during the period of hypocaloric parenteral feeding to mean(s.e.m.) values of 2.3(0.2) and 8.6(0.6) g kg-1 day-1 respectively in bGH-treated animals. By contrast, in saline-treated controls net and whole-body protein catabolism continued to increase during hypocaloric parenteral feeding. There was a significant decrease (P < 0.05) in the rate of [14C]leucine uptake in tissues of the gastrointestinal tract, heart and diaphragm in bGH-treated animals compared with controls. These results demonstrate that daily administration of growth hormone decreases the catabolic response to a metabolic stress, resulting in the conservation of protein in the heart, diaphragm, gastrointestinal tract and musculoskeletal system by a primary anticatabolic action. In addition, growth hormone therapy initiated before induction of the catabolic state enhances the protein-sparing effects of TPN. Further study is justified to determine whether growth hormone therapy initiated before elective or urgent surgery in the nutritionally depleted patient may have a role in reducing the severity of the postoperative catabolic state, particularly in the patient in whom a complicated course is anticipated.
authors.affiliation: Department of Surgery, University of Auckland, New Zealand.
authors.forename: J B
authors.initials: JB
authors.lastname: Koea
authors.forename: R G
authors.initials: RG
authors.lastname: Douglas
authors.forename: J H
authors.initials: JH
authors.lastname: Shaw
authors.forename: P D
authors.initials: PD
authors.lastname: Gluckman
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000187:drug effects; D002417:Cattle; D005230:Fatty Acids, Nonesterified / Q000097:blood; D013006:Growth Hormone / Q000494:pharmacology*; D007334:Insulin-Like Growth Factor I / Q000187:drug effects / Q000378:metabolism; D010289:Parenteral Nutrition, Total; D011506:Proteins / Q000187:drug effects* / Q000378:metabolism; D011994:Recombinant Proteins / Q000494:pharmacology; D012756:Sheep; D013217:Starvation / Q000378:metabolism*
chemical_list: D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D011506:Proteins; D011994:Recombinant Proteins; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone