Plasma concentrations of progestagens, oestrone sulphate and prolactin in pregnant mares subjected to natural challenge with equid herpesvirus-1.
Multiparous pregnant mares, on two studfarms, were studied following natural challenge with equid herpesvirus-1 (EHV-1). They were divided into three groups according to serum complement fixation titres: Group A (N = 11) were not challenged and delivered normal foals; Group B (N = 13) were challenged but delivered normal foals; Group C (N = 23) were challenged and delivered infected foals which were stillborn or lived for less than 31 h. In Groups A and B mean (+/- s.d.) gestational age at delivery was 343 (+/- 8) and 339 (+/- 8) days respectively, whereas in Group C it was significantly (P less than 0.01) shorter (294 +/- 44 days). Group C mares had significantly lower pre-partum concentrations of progestagens except for 2 mares in which the values were comparable to those of mares in Groups A and B; one of these 2 mares delivered a live foal which survived for 31 h. Thin-layer chromatography showed that substances eluting in RF positions similar to 20 alpha-dihydroprogesterone and 5 alpha-pregnane-3,20-dione, were the main progestagen metabolites in plasma at 275-295 and 305-335 days gestation respectively. Incubation of liver, placenta, gonads, kidney and brain revealed no significant difference in the ability of virus-infected and non-infected fetal tissues to metabolize labelled progesterone in the presence of NADPH. Concentrations of plasma oestrone sulphate pre partum, from all groups of mares, were related to gestational age. Plasma prolactin concentrations were elevated at parturition in mares in Groups A and B but lower values were observed in Group C. We conclude that (1) endocrine patterns in maternal peripheral blood of mares with EHV-1 infected fetuses are similar to those of mares carrying normal fetuses and probably are related to gestational age at the time of delivery; and (2) substantial quantities of progestagen metabolites are found in the plasma of late-term pregnant mares.
Ousey
J C
JC
Beaufort Cottage Stables, Newmarket, Suffolk, U.K.
Rossdale
P D
PD
Cash
R S
RS
Worthy
K
K
D000034:Abortion, Veterinary / Q000097:blood; D000818:Animals; D004966:Estrogens, Conjugated (USP) / Q000097:blood; D004970:Estrone / Q000031:analogs & derivatives* / Q000097:blood; D005260:Female; D006566:Herpesviridae Infections / Q000097:blood / Q000662:veterinary*; D004861:Herpesvirus 1, Equid; D006734:Horse Diseases / Q000097:blood*; D006736:Horses; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000662:veterinary; D011374:Progesterone / Q000097:blood*; D011388:Prolactin / Q000097:blood*
D004966:Estrogens, Conjugated (USP); D004970:Estrone; D011374:Progesterone; D011388:Prolactin; C017296:estrone sulfate