Radiolanthanides as Markers for Vitellogenin-Derived Proteins in the Growing Oocytes of the Japanese Quail

Abstract

Producing Japanese quail were given intravenous injections of radiolanthanides as trichlorides in .03N HCl solution. In quail given 15 mumol lanthanide pr 100 g body weight, the liver accumulated 46 to 82% of the dose by 18 hr after the injection. The growing oocytes accumulated 6 to 24% of the dose. The spleen had the greatest concentration of radiolanthanide (14 to 38%/g), the liver 9 to 19%/g, and the most heavily labeled oocytes 3 to 9%/g. The atomic number of the lanthanide for the 9 lanthanides used was not a factor in these accumulations. Levels of 140La were maximal in the membranes of the growing oocytes by 6 hr (4%) and in the contents by 2 days (19%). The smaller the number of mumol the greater was the percent accumulation in the oocytes. Thus, for .015 mumol 140La/100 g, 75% was present in the oocytes by 18 hr. The most heavily labeled oocytes contained 21%/g vs. 2.9%/g for the liver and 1.3%/g for the spleen. The sum of 140La depositions in eggs laid over 8 days (11 quail, 87 eggs) was, per quail, 89.6 +/- .6% (mean +/- SE) of the injected dose. The half-time value for deposition of 140La in the growing oocytes was 1.8 hr. This value represented the rate of loss of labeled vitellogenin from the plasma as vitellogenin-derived proteins were transferred into the oocytes.

153Gadolinium as a Useful Radiolanthanide for Long-Term Labeling of Tissues in Japanese Quail

“…For laying female quail, the accumulations of Gd in tissues were similar in percentage to those reported previously for .015 /nmol La/100 g (Robinson et al, 1980). Again, .15 Mmol/100 g appeared to be the dose that saturated the plasma vitellogenin; above this dose the fraction of the label present in the occytes at 18 hr decreased markedly whereas the fractions in the other tissues increased.…”

“…The La-injected quail may have had so much lanthanide to handle that the plasma clearance of lanthanide was slowed. Such appeared to be the result of "loading" the plasma with La in a previous study (Robinson et al, 1980). In that study 15 Mmol La/100 g gave values for estimates of the biological halftime for plasma vitellogenin of 5.1 and 6.5 hr, whereas 0.15 Mmol La/100 g gave a half-time value of 1.8 hr.…”

“…Solution(s), .15 ml/100 g body weight, were injected into a wing vein. One to 20 hr later, the quail were killed and samples of selected tissues were prepared (as per Robinson et al, 1980) for gamma counting. A 2channel gamma spectrometer and a 7.5 cm diameter X 7.5 cm high Nal(Tl), "well"shaped crystal were used for the radiation measurements.…”

“…A suitable replacement radiolanthanide was sought with a decreased possibility of tissue damage and providing for processing and storage of samples in long-term experiments. A dose level of .015 Mmol La (containing .15 MCi 140 La/200 g body weight), intravenously, provided acceptable levels of labeling in Japanese quail (Robinson et al, 1980). A replacement lanthanide would need a specific activity sufficiently great to provide approximately 10,000 measurable particles per nanomole.…”

“…Mraz et al (1964) found that up to 7% of a dose of !40 lanthanum ( I40 La) administered intramuscularly into chickens was present in the yolks of eggs laid. Lanthanides apparently bind to the plasma vitellogenin of egg-producing Japanese quail, for up to 73% of a dose of radiolanthanide was found in the egg yolks (Robinson et al, 1980) and 94% of the yolk label was in the phosvitin and lipovitellin fractions (Robinson et al, 1979). 140 La was useful for these vitellogenin studies because of the chemical and irradiation properties of the target (purity 99.99% for La, natural abundance 99.911% for 139 La, cross-section 8.8 barns) and the emission of useful gammas with an occurrence of 188%.…”