TY - JOUR
T1 - Effects of hormones and osmolarity in the culture medium on germinal vesicle breakdown of porcine oocytes
AU - Yamauchi, N.
AU - Sasada, H.
AU - Soloy, E.
AU - Dominko, T.
AU - Kikuchi, K.
AU - Nagai, T.
N1 - Funding Information:
The present study was conducted to examine effects of hormones and osmolarity on germinal vesicle breakdown (GVBD) and histone HI kinase (HIK) activity in porcine oocytes cultured in vitro. The basic medium used for culture of oocytes was modified Tyrode's solution in which the osmolarity was adjusted to 134 to 495 mOsm by changing the concentration of sodium chloride (NaCI). When the hormones were present, osmolarity of medium that allows GVBD of oocytes was less than 400 mOsm. However, the range of osmolarityofmediumthatallowsmeioticmaturationofoocyteswas210to362mOsm. On the other hand, without hormonal supplement, the incidence of GVBD in oocytes decreased as the osmolarity of the medium increased in the rage of 210 to 362 mOsm. By increasing the osmolarity of the medium from 210 to 362 mOsm by addition with sorbitol instead of NaCl, the incidence decreased from 89.1 % to 13.3 %. In oocytes cultured in medium of 210 mOsm without hormones, the percentage of oocytes that underwent GVBD and had increased HIK activity 20 h after culture was significantly higher (P<0.05) than those of oocytes cultured in the same medium supplemented with hormones or medium of 362 mOsm. These results indicate that in vitro induction of GVBD in porcine oocytes is strongly affected by osmolarity of the medium in the absence of hormones. The results also suggest that, under low osmolarity (210 mOsm), GVBD is accelerated with rapid increase ofHIK activity. Cl999 by Elsevier SCIence Inc. Key words: hormones, osmolarity, pig, oocytes, GVBD Acknowledgments We are grateful to Dr C. G. Grupen for critical reading and editing of the manuscript. We also thank Dr M. Geshi and Mrs. E. Yamauchi for technical assistance and Mrs. M. Wada for secretarial assistance in preparing this manuscript. This work was supported, in part, by a Grant-in-Aid (Bio Design Program) from the Ministry of Agriculture, Forestry and Fisheries (BDP-98-ill-l-l). 'Present address: Laboratory of Reproductive Endocrinology, National Institute of Animal Industry, PO BOX-5, TSukuba-Norindanchi, Tsukuba, Japan. bCorrespondence and reprint requests.
PY - 1999/7/1
Y1 - 1999/7/1
N2 - The present study was conducted to examine effects of hormones and osmolarity on germinal vesicle breakdown (GVBD) and histone H1 kinase (H1K) activity in porcine oocytes cultured in vitro. The basic medium used for culture of oocytes was modified Tyrode's solution in which the osmolarity was adjusted to 134 to 495 mOsm by changing the concentration of sodium chloride (NaCl). When the hormones were present, osmolarity of medium that allows GVBD of oocytes was less than 400 mOsm. However, the range of osmolarity of medium that allows meiotic maturation of oocytes was 210 to 362 mOsm. On the other hand, without hormonal supplement, the incidence of GVBD in oocytes decreased as the osmolarity of the medium increased in the rage of 210 to 362 mOsm. By increasing the osmolarity of the medium from 210 to 362 mOsm by addition with sorbitol instead of NaCl, the incidence decreased from 89.1% to 13.3%. In oocytes cultured in medium of 210 mOsm without hormones, the percentage of oocytes that underwent GVBD and had increased H1K activity 20 h after culture was significantly higher (P<0.05) than those of oocytes cultured in the same medium supplemented with hormones or medium of 362 mOsm. These results indicate that in vitro induction of GVBD in porcine oocytes is strongly affected by osmolarity of the medium in the absence of hormones. The results also suggest that under low osmolarity (210 mOsm), GVBD is accelerated with rapid increase of H1K activity.
AB - The present study was conducted to examine effects of hormones and osmolarity on germinal vesicle breakdown (GVBD) and histone H1 kinase (H1K) activity in porcine oocytes cultured in vitro. The basic medium used for culture of oocytes was modified Tyrode's solution in which the osmolarity was adjusted to 134 to 495 mOsm by changing the concentration of sodium chloride (NaCl). When the hormones were present, osmolarity of medium that allows GVBD of oocytes was less than 400 mOsm. However, the range of osmolarity of medium that allows meiotic maturation of oocytes was 210 to 362 mOsm. On the other hand, without hormonal supplement, the incidence of GVBD in oocytes decreased as the osmolarity of the medium increased in the rage of 210 to 362 mOsm. By increasing the osmolarity of the medium from 210 to 362 mOsm by addition with sorbitol instead of NaCl, the incidence decreased from 89.1% to 13.3%. In oocytes cultured in medium of 210 mOsm without hormones, the percentage of oocytes that underwent GVBD and had increased H1K activity 20 h after culture was significantly higher (P<0.05) than those of oocytes cultured in the same medium supplemented with hormones or medium of 362 mOsm. These results indicate that in vitro induction of GVBD in porcine oocytes is strongly affected by osmolarity of the medium in the absence of hormones. The results also suggest that under low osmolarity (210 mOsm), GVBD is accelerated with rapid increase of H1K activity.
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U2 - 10.1016/S0093-691X(99)00117-X
DO - 10.1016/S0093-691X(99)00117-X
M3 - Article
C2 - 10734413
AN - SCOPUS:0033167287
SN - 0093-691X
VL - 52
SP - 153
EP - 162
JO - Theriogenology
JF - Theriogenology
IS - 1
ER -