Annual variations in the total lipid and protein content of the liver, fat body, ovary and plasma of the female frog (Rana esculenta L.).

The concentrations of lipid and protein in the ovary, fat body, liver and plasma of the female frog (Rana esculenta L.) were found to exhibit marked seasonal variations. There was an interesting correspondence between the depletion of lipid in the plasma and fat body and an increased level of lipid in the ovary. It would appear that oestrogenic steroids stimulate and increase the concentrations of lipids in the plasma, whereas pituitary gonadotrophins influence the uptake of lipids by ovarian tissue for vitellogenesis.