Relationship Between Plasma Free Fatty Acid Levels and Human Placental Lactogen Secretion in Late Pregnancy ULYSSE J. GASPARD, ALFRED S. LUYCKX, ANDR£ N. GEORGE, AND PIERRE J. LEFEBVRE Department of Obstetrics and Gynecology and Division of Diabetes, Institute University of Liege, Liege, Belgium ABSTRACT. In order to determine whether changes in free fatty acid (FFA) levels affect hPL secretion in late human pregnancy in the same way as they affect human growth hormone (hGH) secretion, two types of experiments were performed: 1) I g of nicotinic acid (NA) was infused for 60 min in II patients and 1.5 g of NA was infused for 90 min in 8 additional patients; 2) triglycerides and heparin were administered iv for 120 min in 5 control cases and, in 11 other patients 0.3 U insulin/kg BW was injected at the 45th min of the triglycerideheparin infusion. Maternal blood glucose (BG), plasma triglycerides (TG), FFA, immunoreactive insulin (IRI) and hPL levels were sequentially determined in the course of these experiments. In both series of patients, the NA infusion resulted in substantial depression of FFA levels to around 50% of mean basal levels. The hPL levels displayed only negligible fluctuations, although FFA depression persisted for more than 2 hours. During the lipid-heparin infusion, an increase in plasma TG and an accompanying rise in FFA levels (from
T
HE EXTENSIVE structural homology (1,2) and immunologic cross-reactivity (3,4) between human placental lactogen (hPL) and human pituitary growth hormone (hGH) may explain why these two hormones share some biological actions, such as stimulation of lipolysis demonstrable in vitro (5-7) and in vivo (8). Although the secretion of hPL is considered by some authors to be autonomous (9, review in 10), various findings which have been discussed in previous papers (11,12), support the idea that, at least in part, hPL secretion responds as does hGH to
Received August 30, 1976. Supported by the Fonds National de la Recherche Scientifique (FNRS), Belgium. Reprint requests to: Ulysse J. Gaspard, M.D. Clinique de Gyne'cologie et d'Obste'trique, Universite de Liege, 81, boulevard de la Constitution, 4020 Liege, Belgium.
of Medicine,
629 ± 48 to 1,919 ± 301 /ueq/1) were recorded. When insulin was infused together with lipids, the ensuing hypoglycemia (average glycemia: 32.3 ± 3 mg/100 ml) resulted in a significant increase in hPL levels (mean peak rise: +26.3% of mean preinsulin values, P values between
T
HE EXTENSIVE structural homology (1,2) and immunologic cross-reactivity (3,4) between human placental lactogen (hPL) and human pituitary growth hormone (hGH) may explain why these two hormones share some biological actions, such as stimulation of lipolysis demonstrable in vitro (5-7) and in vivo (8). Although the secretion of hPL is considered by some authors to be autonomous (9, review in 10), various findings which have been discussed in previous papers (11,12), support the idea that, at least in part, hPL secretion responds as does hGH to
Received August 30, 1976. Supported by the Fonds National de la Recherche Scientifique (FNRS), Belgium. Reprint requests to: Ulysse J. Gaspard, M.D. Clinique de Gyne'cologie et d'Obste'trique, Universite de Liege, 81, boulevard de la Constitution, 4020 Liege, Belgium.
of Medicine,
629 ± 48 to 1,919 ± 301 /ueq/1) were recorded. When insulin was infused together with lipids, the ensuing hypoglycemia (average glycemia: 32.3 ± 3 mg/100 ml) resulted in a significant increase in hPL levels (mean peak rise: +26.3% of mean preinsulin values, P values between
