Growth hormone 24‐h serum profiles during pregnancy—lack of pulsatility for the secretion of the placental variant

Abstract

Serum profiles of growth hormone (GW) were recorded for 24 h in women at different stages of normal pregnancy. Two monoclo~ial antibodies directcd against different epitopes and unaffected by human placental lactogen werc used in radioimniunoassays to distinguish the pituitary 22K-GH from the placental GH variant. The 'normal' episodic peak activity of GH in nun-pregnant and first trimester pregnant womcn was dramatically changed into a continuous very stable secretion during late pregnancy. This change was first observed at 17 weeks gestation. It is concluded that during the second half of pregnancy, serum rneasurcinents of GH reflect a major contribution frotn a non-cpisodically secreted placental GH variant and a concomitant suppression of pituitary GH. This specific signal, i.e. a continuous GH secretion, may be an important regulator of maternal liver metabolism during pregnancy.Growth hormone ((311) is a major mctabolic rcgulatory hormone which stimulates protein synthesis and has profound effects on carbohydrates and lipid metabolism (Merimee 1979). In recent studies on the physiology of growth hormone in pregnant women (Frankcnne rt al. 1988). we have shown that maternal serum levels of the pituitary 22K hGH, encoded by the GH-N

Kinetics and secretion of placental growth hormone around parturition

“…It is found in high concentrations during the last half of pregnancy, and at the same time pituitary GH is virtually absent in plasma (4,5). The regulation and physiology of PGH is far from being understood, but the secretion of PGH is described as non-pulsatile (7). Pituitary GH has a well-known impact upon adipose tissue metabolism (25,26), and PGH binds equally as well as GH to GHBP (11), which is the extracellular part of the GH receptor.…”

“…Maximum levels of PGH approach acromegalic levels of GH around gestational weeks 35 -37 (3 -6). Pulsatile secretion is not a feature of PGH (7), justifying single blood sample evaluation of PGH levels. It is controversial whether PGH levels decline in the last weeks of pregnancy.…”

Embryonic growth and the evolution of the mammalian Y chromosome. II. Suppression of selfish Y-linked growth factors may explain escape from X-inactivation and rapid evolution of Sry

“…At term their levels exceed 0.0 15 ,ug mL . As expected, concentrations of PL and PGH in foetal serum are much lower than concentrations in maternal serum (Frankenne et a!., 1988;Eriksson et al, 1989;Walker et al, 1991). Haig(1993) details further evidence consistent with the involvement of placental lactogens in maternal/f oetal conflict.…”

Human placental growth hormone is increased in maternal serum at 20 weeks of gestation in pregnancies with large-for-gestational-age babies

“…The protein sequences of GH-N and GH-V are highly conserved (93% amino 83 acid identity); however, they have distinct expression profiles. GH-N is mainly secreted in a 84 pulsatile fashion from the pituitary, while GH-V is secreted from the placenta tonically 85 during human pregnancy (Eriksson et al, 1989). The pituitary protein, GH-N (22kDa), is the 86 primary form of GH in maternal circulation up to 15 weeks of gestation (Eriksson et al, 87 1988).…”