Somatomedin activity in synovial fluid.

Abstract

SUMMARY Abnormalities of synovial fluid, as a lubricant and nutrient, may have relevance to the causation of certain articular diseases. The somatomedin activity in normal synovial fluid obtained from the knee joint of the ox has been studied and compared with the activity in serum from the same animal. The porcine costal cartilage bioassay of Van den Brande and Du Caju (1974) has been used with the isotopes 35S-sulphate and 3H-thymidine. The mean potency ratio of ox synovial fluid in terms of ox serum for 35S-sulphate incorporation was 0-28 (range 0 19-0'47) and for 3H-thymidine incorporation 0*35 (range 0-21-0*63). A significant correlation was found between the somatomedin activity (as measured by 35S-sulphate incorporation) and the total protein and albumin concentrations in the ox synovial fluids and the ox sera, but there was no significant relationship between the somatomedin potency ratios and the globulin concentrations. The possible relevance of these findings to injury and disease in synovial joints is discussed.

Somatomedin activity and growth hormone levels in body fluids of the fetal pig: effect of chronic hyperinsulinaemia

“…The origin of the somatomedin activity in lung fluid is not known although human embryonic lung fibroblasts have been shown to produce somatomedin in vitro (Atkinson, Weidman, Bhaumick & Bala, 1980). Somatomedins have also been detected in other extra-circulatory fluids (Beaton et al 1975;Coates et al 1977). The occurrence of somatomedin activity in lung fluid could implicate these hormones in fetal lung growth if somatomedins act primarily as paracrine or autocrine factors in utero.…”

“…Somatomedins are found not only in blood but also in many other body fluids (Andersen, Kastrup & Lebech, 1974;Beaton, Sagel & Distiller, 1975;Wright & Bala, 1975;Coates, Burwell, Buttery, Walker & Woodward, 1977). We have investigated the activity of somatomedin in plasma, amniotic fluid and lung fluid in fetal pigs, its relationship to the body weight of the fetuses and the effects of insulin treatment on both body weight and somatomedin activity.…”

Mitogenic effects of hydroxyapatite and calcium pyrophosphate dihydrate crystals on cultured mammalian cells

“…If HA or CPPD crystals are indeed "competence"-promoting factors, they mpy be responsible for synovial cell proliferation in the crystal deposition diseases, since the factors in plasma needed for "progression" (such as somatomedin) are present in synovial fluid (26,27), which is largely a dialysis of plasma (28).…”

Mitogenic activity of hydroxyapatite: Requirement for somatomedin C

“…Both HA crystals and PDGF require Sm-C for full mitogenic activity. Stimulation by HA crystals may contribute to the documented synovial cell proliferation in calcium crystal deposition diseases, since factors needed for "progression" (such as somatomedin) are present in synovial fluid (Coates et al, 1977(Coates et al, ,1978.…”