Somatomedin-A (Sm-A) bioactivity in serum and amniotic fluid as related to weight in the fetal pig
Year: 1980
Type: article
Abstract: Serum and amniotic fluid Sm-A bioactivity has been assayed in the fetal pig using a double labelling technique. 3 H-thymidine activity was always higher in fetusesand lower in sows than 35 S activity.35 SO 4 uptake was not stimulated or was inhibited in about 30 p. 100 of the fetal sera.3 H-thymidine uptake was stimulated in all of them.There was a significant correlation (P < 0.001) between fetal weight and serum Sm, as judged with both 35 50 4 and 3 H-thymidine.No correlation was found between fetal weight and amniotic fluid Sm, between amniotic fluid and serum Sm or between 35 50 4 and 3 H activities.It is concluded that the latter activities were due to two or more factors instead of only one. Introduction.Little is known about the role of hormones in the growth and differentiation of fetal tissues.Though fetal plasma contains large quantities of growth hormone, fetal growth is not appreciably perturbed by a deficiency of intrauterine growth hormone (Nanagas, 1925 ; Blizzard and Alberts, 1956 ; Rimoin, Merimee and McKusick, 1966).Similarly, normal growth has been observed in rat, rabbit, sheep and monkey fetuses after in utero decapitation or hypophysectomy (Jost, 1966 ; Liggins and Kennedy,1968 ; Chez et al., 1970).It is now believed that growth hormone does not act directly on skeletal growth but through the mediation of small peptidic growth factors, the somatomedins.Soma- tomedin-A (Sm-A) bioactivity has been defined as the factor stimulating S0 4 uptake into chick embryo pelvis in vitro (Uthne, 1973).Somatomedins are found not only in blood, but in other body fluids such as the cerebrospinal fluid (Beaton, Sagel and Dis- tiller, 1975) or amniotic fluid (Andersen, Kastrup and Lebech, 1974 ; Wright and Bala, 1975 ; Bala and Smith, 1976).Some authors studying humans have reported a significant correlation between birth size and Sm-P (Gluckman and Brinsmead, 1976), Sm-C (Underwood et al., 1978) or NSILA (Heinrich et al., 1978) in cord blood.We wondered if these correlations could be found in animals.The pig was chosen as suitable biological material for within-litter comparisons since it produces a large number offetuses per litter.Moreover, the individuals of a same litter have very hetero- geneous weight and size, thus facilitating our study.
DOI: 10.1051/rnd:19800213
Author: J. CHARRIER
Language: English
Subfield: Endocrinology, Diabetes and Metabolism
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W2000714509