PubMed Health⌕ Search

Biomedical subjects

G B Reed

Publications and source records attributed to G B Reed.

At least 19 recordsLinked to original sources
PubMed1983

Comparative effects of insulin and hydrocortisone on glycogen content of fetal and newborn rat liver cultures.

Organ cultures prepared from 18- to 19-day fetal and 3- to 6-day-old newborn rat liver were maintained for 2 days in Trowell's T8 medium without insulin and supplemented with 0.1% albumin and 300 mg% glucose. The atmosphere for culture was 95% O2 and 5% CO2. Medium alone was used for control cultures, whereas insulin, hydrocortisone, or insulin plus hydrocortisone were used in experimental groups. Explant glycogen stores were maintained better in cultures grown in hormone-supplemented media than in control cultures. Fetal explants were found to have higher levels of glycogen than controls in the insulin or insulin plus hydrocortisone groups. Postnatal explants did not have higher levels of glycogen in the hormone-treated groups. Gestational age appeared to determine whether the liver explants reacted to hydrocortisone or insulin to maintain glycogen stores. Enzymatic assays, in vitro of glycogen synthetase and phosphorylase, indicated that the fetal liver response to insulin plus hydrocortisone by increasing the total and independent form of glycogen synthetase; but similar enzyme studies on postnatal rat liver did not show convincing differences as to an effect on synthetase. No definite in vitro temporal relationships could be identified. Late in gestation, the effect of hydrocortisone on glycogen synthesis is apparently dependent on the presence of insulin. Insulin appears to be required for glycogen storage in vitro in the cultures of postnatal rat liver.

Animals↗
PubMed1975

Insulin and hydrocortisone effects on viability and glycogen stores of postnatal rat liver organ culture.

Organ cultures prepared from 3- to 6-day-old newborn rat liver were maintained for as long as 6 days in medium CMRL-1066 supplemented with horse serum, glucose, and L-glutamine; the atmosphere for culture was 95 per cent O2 and 5 per cent CO2. Medium alone was used for control cultures, whereas insulin, hydrocortisone, or insulin plus hydrocortisone were used in experimental groups. Explant glycogen stores and viability were better preserved in cultures grown in hormone-supplemented media than in control cultures. Insulin caused glycogen storage of explant glycogen. Results of light and electron microscopic abservations are confirmed by isotope studies. The effect of hydrocortisone on glycogen synthesis is apparently dependent on the presence of insulin, and insulin appears to be required for glycogen storage in vitro in these cultures of postnatal rat liver.

Animals↗