Hostname: page-component-7c8c6479df-hgkh8 Total loading time: 0 Render date: 2024-03-28T11:07:35.515Z Has data issue: false hasContentIssue false

Relationship between the appearance of preantral follicles in the fetal ovary of Antarctic minke whales (Balaenoptera bonaerensis) and hormone concentrations in the fetal heart, umbilical cord and maternal blood

Published online by Cambridge University Press:  09 August 2004

Yuki Muranishi
Affiliation:
Department of Food Production Science, Obihiro University of Agriculture and Veterinary Medicine, Obihiro 080-8555, Japan.
Motoki Sasaki
Affiliation:
Department of Veterinary Anatomy, Obihiro University of Agriculture and Veterinary Medicine, Obihiro 080-8555, Japan.
Kengo Hayashi
Affiliation:
Department of Life Science, Obihiro University of Agriculture and Veterinary Medicine, Obihiro 080-8555, Japan.
Norihito Abe
Affiliation:
Department of Food Production Science, Obihiro University of Agriculture and Veterinary Medicine, Obihiro 080-8555, Japan.
Takuma Fujihira
Affiliation:
Department of Food Production Science, Obihiro University of Agriculture and Veterinary Medicine, Obihiro 080-8555, Japan.
Hajime Ishikawa
Affiliation:
The Institute of Cetacean Research, Tokyo 104-0055, Japan.
Seiji Ohsumi
Affiliation:
The Institute of Cetacean Research, Tokyo 104-0055, Japan.
Aiko Miyamoto
Affiliation:
Department of Life Science, Obihiro University of Agriculture and Veterinary Medicine, Obihiro 080-8555, Japan.
Yutaka Fukui
Affiliation:
Department of Food Production Science, Obihiro University of Agriculture and Veterinary Medicine, Obihiro 080-8555, Japan.

Abstract

The present study aimed to determine the relationship among changes in the number of preantral follicles and concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH), progesterone (P4), androstenedione (A) and estradiol-17β (E2) in the fetal heart, umbilical cord and maternal blood. Primordial follicles had already appeared in a 20 cm fetus and primary follicles were observed in a 50 cm fetus. In a 70 cm fetus, the number of primordial and primary follicles increased rapidly and secondary follicles were present. The concentrations of LH and FSH did not change between 20 cm and 160 cm in fetal length. When the fetal length became >70 cm, serum levels in the fetus, umbilical cord and mothers, and E2 levels in umbilical cord increased synchronously (p<0.05). These results showed increases in the number of preantral follicles in the Antarctic minke whale fetal ovary along with fetal growth during the early gestation period. These findings suggest that the change in preantral follicles was associated with changes in the concentration of steroids in early gestation periods. The changes in steroid concentrations in the fetal and umbilical cord blood and the increased number of preantral follicles were coincident at around 70 cm in fetal length, whereas the growth and differentiation of primordial and primary follicles appeared to be independent of FSH and LH.

Type
Research Article
Copyright
2004 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)