Effects of passive immunization against oestradiol-17beta and inhibin on the secretion of gonadotrophin in the cyclic golden hamster (Mesocricetus auratus).
To investigate the physiological importance of oestradiol-17beta and inhibin in the regulation of gonadotrophin secretion in the cyclic golden hamster, females were passively immunized against two hormones. When 200 microL antiserum against oestradiol-17beta (oestradiol-AS) was given on Day 3 (Day 1 = day of ovulation), the preovulatory gonadotrophin surge was completely blocked for 24 h and the length of the oestrous cycle was also prolonged for one day. In the group given 200 microL oestradiol-AS on Day 3, basal levels of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) increased slightly and superovulation (19.6+/-0.8, mean+/-s.e.m.) occurred. When 200 microL antiserum against inhibin (inhibin-AS) was given at 1100 hours on Day 3, a dramatic increase in plasma FSH and a slight increase in LH were noted, resulting in superovulation (38.2+/-2.6) on the expected Day 1. The present study indicates clearly that inhibin plays a major role in regulating the specific ovulation rate in the hamster through the control of FSH secretion. Present results also indicate that oestradiol-17beta suppresses basal LH secretion. Oestradiol-17beta may act as an indicator of the follicular maturation, and the high plasma concentration of oestradiol-17beta noted from Day 3 to Day 4 may play an important role in determining the timing of initiation of the preovulatory gonadotrophin surge.
Kishi
H
H
Laboratory of Veterinary Physiology, Tokyo University of Agriculture and Technology, Fuchu, Japan.
Okada
T
T
Kawazu
S
S
Otsuka
M
M
Taya
K
K
Watanabe
G
G
Sasamoto
S
S
D000818:Animals; D006224:Cricetinae; D004958:Estradiol / Q000276:immunology*; D004971:Estrus / Q000187:drug effects*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000378:metabolism*; D007116:Immunization, Passive; D007265:Inhibins / Q000276:immunology*; D007986:Luteinizing Hormone / Q000378:metabolism*; D008647:Mesocricetus
D004958:Estradiol; D007265:Inhibins; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone