Acute stimulatory effects of an LH-RH agonist on the ovary in pseudopregnant rats.
Pseudopregnant rats were anaesthetized on day 5 of pseudopregnancy with pentobarbital and hypophysectomy or sham operation was performed. Polyethylene cannulas were inserted into one of the femoral arteries and utero-ovarian veins. Five-minute blood samples were collected from the ovary for 40 minutes. Following the first five minute blood fraction LH-RH, an agonistic analogue (D-Phe6, des Gly-NH10(2)-LH-RH-ethylamide) or an antagonistic analogue (Formyl-D-Tryp1,3, D-pCl-Ph2, D-Phe6LH-RH) were superfused into the ovarian bursa for 5 minutes in a volume of 50 microliters. Blood pressure, ovarian venous outflow and haematocrit were continuously measured. From the blood samples progesterone and oestradiol-17 beta were determined by RIA and the secretion rate was calculated. It was found, that LH-RH and its antagonistic analogue has no effect on the blood flow, progesterone (P) and oestradiol-17 beta (E2) secretion of ovary. However, an agonistic analogue of LH-RH induced a rapid elevation of blood flow, diminished vascular resistance in the ovary, and in a dose of 50 ng increased the secretion rate of E2. In sham operated animals the effects of agonistic analogue was similar to the effects of 1.0 IU of hCG.
Varga
B
B
National Institute of Occupational Health, Budapest, Hungary.
Horváth
E
E
Ungváry
G
G
Stark
E
E
D000818:Animals; D004958:Estradiol / Q000378:metabolism; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000008:administration & dosage / Q000494:pharmacology*; D007016:Hypophysectomy; D010053:Ovary / Q000098:blood supply / Q000187:drug effects* / Q000378:metabolism; D011374:Progesterone / Q000378:metabolism; D011555:Pseudopregnancy; D051381:Rats; D011919:Rats, Inbred Strains; D013268:Stimulation, Chemical
D007987:Gonadotropin-Releasing Hormone; D011374:Progesterone; D004958:Estradiol